生酮飲食

 

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  • 更新日期:2022年3月24日

  • 編寫者:郭漢聰


  • 生酮飲食(Ketogetic Diet)顧名思義,就是能產生酮體的飲食。藉由減少會生成葡萄糖的食物攝取量,例如:非纖維的碳水化合物與某些胺基酸(glucogenic amino acids),逼迫身體分解脂肪酸,製造酮體(ketone bodies)來供應能量,也就是讓身體的能源系統從燃燒葡萄糖為主轉換為燃燒酮體為主。

  • 生酮飲食是一種超低醣、低蛋白、高脂肪的飲食。(通常脂肪攝取量占總熱量的80%以上)

  • Dr. Russel Wilder為了複製斷食的療效,特地模仿斷食的營養狀態(超低醣、低蛋白、高脂),設計了一套能產生酮體的飲食法,並把它命名為【生酮飲食】。

  • 自然進入生酮狀態的常見情況:
    1.長時間飢餓
    2.長時間斷食
    3.長時間運動

  • 斷食可以快速進入生酮狀態,並且幫助初學者在較短時間內達到【生酮適應】,但是斷食還是有風險,旁邊必須有人伴隨,以應付緊急狀況。關於斷食的種種注意事項,請參考→斷食篇

【絕對禁忌症】

  • 原發性肉鹼缺乏症 (primary carnitine deficiency)

  • 脂肪酸氧化途徑缺陷 (fatty acid oxidation pathway defect)

  • 遺傳性丙酮酸羧化酶缺乏 (pyruvate carboxylase deficiency)

  • 紫質症 (porphyria)

【相對禁忌症】--以下情形必須在生酮專家監督下才能實施生酮飲食

  • 懷孕中、哺乳中

  • 小孩 (發育期不適合限制蛋白質)

  • 無法戒酒者

  • 原發性肝癌或轉移型肝癌

  • 肝酵素過高(有肝損傷情形)

  • 影響胃腸功能的手術(例如:食道手術)

  • 第一型糖尿病

  • 控制不良的第二型糖尿病或服用SGLT2抑制劑者

  • 胃繞道手術

  • 止痛劑(嗎啡)造成的頑固便秘

  • 吞嚥困難者

  • 神經受損造成的腸胃蠕動緩慢

  • 膽囊阻塞

  • 胰臟炎

  • 心臟病

  • 腎臟病

  • 短腸症後群

  • 癌症惡質病

  • 血液檢驗不及格者

  • 免疫機能受損者

  • 編者補充:以上情形,不是不能實施生酮飲食,而是要配合生酮專家才能保障安全。另外,請參考→低醣飲食的副作用

【生酮不適症】

【生酮飲食的熱量比例】

  • 各種生酮版本的熱量比例:

    各種生酮或斷食版本

    特殊目的

    醣類(%)

    蛋白質(%)

    脂肪(%)

    纖維(克數)

    醣類(克數)

    蛋白質(克數)

    脂肪(克數)

    Eric Crall

    5

    20

    75

       

     

     

    Eric Berg

    5~10

    25

    65~80

       

     

     

    Maria Emmerich

     

     

     

     

    低於30克

    0.7~0.8克/每公斤淨瘦肉體重

     

    代謝疾病

     

     

     

     

    低於20克

    0.7~0.8克/每公斤淨瘦肉體重

     

    Ellen Davis

    治癌

    2~4

    9~11

    65~80

       

     

     

    Nasha Winters

    治癌

    5~10

    20~25

    70~75

     

    低於20克

     

     

    Jeff Volek
    Stephen Phinney

    預防肌肉流失

             

    1.3~2.2克/每公斤淨瘦肉體重

     

    Jacob Wilson

    預防肌肉流失

    低於10

    20~30

    60~80 至少15克  

    高於1.0~1.2克/每公斤淨瘦肉體重

    低於1.7克/每公斤淨瘦肉體重

     

    Marty Kendall

    營養素充足

     

    20

         

    1.8克/每公斤淨瘦肉體重

     

    Valter Longo

    Steven Gundry

    長壽

             

    0.37克/每公斤體重

     

    PSMF

    預防肌肉流失

     

     

       

    低於20克

    2.2克/每公斤淨瘦肉體重

    40~50克

    Ron Rosedale

             

    0.75克/每公斤淨瘦肉體重

     

    糖尿病

             

    低於0.6克/每公斤淨瘦肉體重

     

    癌症

             

    低於0.45克/每公斤淨瘦肉體重

     
    • 淨瘦肉體重=體重-體脂

    • PSMF=Protein-Sparing Modified Fasting=保留蛋白質的改良式斷食法。請參考→PSMF

     

  • 使用熱量比例來創造生酮狀態是比較不可靠的,如果總熱量過多,按照比例換算出來的生糖物質也會跟著過多,最後還是會脫離生酮狀態。例如:如果每天攝取2000卡,按照生酮飲食的醣類比例(5%)來計算,每天的醣類攝取量大約是25克(2000 x 5% ÷ 4),即使加入某些蛋白質的生糖量,萄萄糖的總量也不至於太高,生酮的機率非常高,反之,如果每日攝取總量是4500卡,5%相當於攝取了56.25克醣類(4500 x 5% ÷ 4),再加上某些蛋白質的生糖量,萄萄糖的總量就會太多,生酮的機率就低很多了。

【各種生酮狀態】

  • 狀態

    血酮濃度
    (BHB, mmol/L)

    混合飲食

    0.1~0.2

    一夜斷食(混合飲食)

    <0.5

    營養性生酮狀態

    0.5~5.0

    醫療性生酮狀態

    2.0~7.0

    飢餓

    5.0~8.0

    糖尿病酮酸血症

    15~20

    • 健康成年人很少會出現BHB高於5.0mmol/L的情形,例外是:斷食狀態、劇烈運動、大量補充外酮。

    • Thomas Seyfried版本的醫療性生酮狀態是:BHB高於3.0 mmol/L。而且還要注意葡萄糖/酮體的比值(GKI)。(詳見→GKI)

  • Jacob Wilson版本-《The Ketogenic Bible》

    狀態

    酮體

    血糖

    血液pH

    結果

    正常醣類飲食

    0~0.4

    80~120

    不變

     

    斷食、生酮飲食

    0.5~7

    60~120

    不變

    改善健康

    糖尿病酮酸血症

    >15~25

    >200

    極酸性

    可能致命

     

  • Nora Gedgaudas的版本-《Primal Fat Burner》

    空腹血酮

    要低於 7 mmol/L

    非空腹血酮

    要低於 15~25 mmol/L

 

葡萄糖/酮體(GKI)

  • 如果想利用治療性生酮狀態來治療一些慢性疾病,例如:癌症、阿茲海默症、帕金森氏症、失智症,光是血糖正常化還不夠,還要再控制【血糖/血酮】的比值,也就是所謂的GKI。

  • Nora Gedgaudas的GKI理想值:0.7~2.0

  • Thomas Seyfried設計了GKI比值來評估癌患的狀況。

  • GKI是葡萄糖/酮體的比值,數值越低代表身體慢慢由燃燒葡萄糖轉向燃燒酮體。(G=葡糖糖,K=酮體。)

  • 採用生酮飲食治療癌症者,必須設法達到GKI小於1。癌患的GKI常常大於50

  • 患的酮體濃度最好保持在3.0mmol/L以上,血糖濃度在70mg/dL以下。

  • GKI要小於10,才算是低胰島素狀態,沒有明顯的胰島素抗阻。

  • GKI採用的單位是mmol/L。(葡萄糖也要把mg/dL的數值除以18,換算成mmol/L。)

  • 各種GKI的組合:

     

    HbA1c

    average blood glucose

    ketones

    GKI

    %

    mg/dL

    mmol/L

    mmol/L

    low normal

    4.1

    70

    3.9

    4.0

    1.0

    optimal

    4.5

    83

    4.6

    2.5

    1.8

    excellent

    < 5.0

    < 97

    < 5.4

    > 0.3

    18

    good

    < 5.4

    < 108

    < 6

    < 0.3

    30

    danger

    > 6.5

    > 140

    > 7.8

    < 0.3

    39

  • 即使實施生酮飲食,一般人還是很難達到GKI小於2,除非是實施斷食。(參考下圖)

  • 當血糖高於6.0 mmol/L (108 mg/dL)時,酮體幾乎是不存在的。

  • 當血液總能量與胰島素上升時,Acetoacetate會轉換成BHB,所以攝取過多外酮容易導致BHB過高,造成一種假象的低GKI,所以現在已經有人採用呼吸出來的丙酮濃度(Breath Acetone)來取代β-羥基丁酸(BHB)作為酮體的代表,這樣才能導入真正理想的生酮狀態:血糖夠低+能量沒有過剩。(編者補充:能量過剩→NADH增加→Acetoacetate轉換成BHB。)

  • 有嚴重胰島素抗阻、癲癇、病態肥胖或癌症者,可能需要進入更深層的生酮狀態,而不僅僅是達到正常血糖值或正常糖化血色素而已。但是,要達到更深層的生酮狀態,需要配合紀律、營養補充品與更嚴苛的食物篩選。

  • https://www.youtube.com/watch?v=96dv7Xrgksw&feature=youtu.be&fbclid=IwAR3hJu-nM20lVdh4fV7rm5hvc8RWZdDBOUVOq6xiR2OFEVCime66eOh8dFI

    GKI

     

     

    30~50

    美國標準飲食

     

    ≧9

    脫離生酮狀態

     

    6~9

    低度生酮狀態

    • 減重、維持體重

    3~6

    中度生酮狀態

    • 治療糖尿病、胰島素抗阻、肥胖

    1.5~3

    高度生酮狀態

    • 治療阿茲海默症、帕金森氏症、腦部創傷

    0.7~1.5

    自噬作用達最高峰

    • 飢餓狀態下

    • 生長減緩

【血糖 Vs BHB】

  • 下圖是採用BHB來計算GKI。

  • β-羥基丁酸(BHB)的單位是採用mmol/L。

  • 血糖的單位是採用mmol/L。

【血糖 Vs 呼吸丙酮】

  • 下圖是採用呼吸丙酮來計算GKI。

  • 呼吸丙酮的單位是採用Ketonix scale的0~100劃分法。

  • 血糖的單位是採用mmol/L

     

  • 下圖是採用呼吸丙酮來計算GKI。

  • 呼吸丙酮的單位是採用Ketonix scale的0~100劃分法。

    血糖的單位是採用mg/dL。(與上圖比較,血糖的單位不同,但是圖形還是很類似。)

 

 

【生酮飲食與三大巨營養素】

  • 要進入生酮狀態,血糖必須降低到55~75mg/dL之間,光靠限制醣類是不夠的,還必須限制蛋白質與總卡路里。但是如果卡路里過低或蛋白質過低,身體就會啟動保護機制,減少甲狀腺素T3,降低新陳代謝來避免肌肉被分解掉。此時如果破壞保護機制,刻意補充T3,就可能造成肌肉流失。(http://www.ketotic.org/2014/12/the-effect-of-ketogenic-diets-on.html)

  • 限制蛋白質是要減少蛋白質透過糖質新生作用轉化成葡萄糖,同時減少癌細胞的主食之一:麩醯胺酸(Glutamine)。(關於蛋白質,請參考→生酮飲食與蛋白質)

  • 醣類的攝取量必須降低到每日25克以下。(編者補充:生酮飲食的眾多版本中,幾乎都規定每日醣類攝取量要低於50克。)

  • 若要迅速降血糖升酮體,建議每日淨糖值要低於12克。(淨糖值=醣類-纖維)

麩醯胺酸

  • 葡萄糖與麩醯胺酸是癌細胞的2大主食,除此之外,癌細胞還有其他食物來源,例如:脂肪酸、酮體、乳酸。

  • 麩醯胺酸的角色很奇妙,除了餵養癌細胞之外,它也是修復腸黏膜的好材料,常用於化療後的腸道修復。

  • 化療期間,癌細胞可以將麩醯胺酸(Glutamine)、甘胺酸(Glycine)與半胱胺酸(Cyteine)合成為強大的抗氧化劑--穀胱甘肽(Glutathione),來中和化療藥物的氧化破壞力。由於麩醯胺酸是身體含量最豐富的氨基酸,幾乎遍布全身,無所不在,同樣地,甘胺酸也很容易取得,所以,如果癌細胞真要取用麩醯胺酸當食物,來源是不虞匱乏的。因此,在化療期間,如果要利用麩醯胺酸來修復腸道,同時又不想癌細胞合成穀胱甘肽來中和化療的藥效,最好的策略是減少半胱胺酸(Cyteine),而不是減少麩醯胺酸或甘胺酸。

  • 癌症期間,如果肌肉逐漸流失,是代表身體需要較多的麩醯胺酸,因為癌細胞把麩醯胺酸分解了。但是最好的解決方法是限制麩醯胺酸分解酵素(glutaminase or ketoglutarate dehydrogenase)的作用,而不是限制麩醯胺酸的食物來源,因為限不限制麩醯胺酸的食物來源都無法阻止癌細胞從身體各部位就地取材(麩醯胺酸)。

  • 癌症雞尾酒療法創始人Jane McLelland指出,根據各種癌細胞的燃料偏好程度,必須調整三大燃料的比例(葡萄糖:麩醯胺酸:脂質)。大致上,所有的癌症種類都應該減少醣類與飽和脂肪的攝取量,另外,以麩醯胺酸為燃料的癌症種類必須減少蛋白質的攝取量,而以脂肪為燃料的癌症種類,例如:攝護腺癌、黑色素瘤,則應該避免生酮飲食。

  • 目前治癌策略有所謂的Press-Pusle的方法,也就是壓法+脈衝法。壓法就是持續加壓來達到殺死大多數癌細胞的目的,作法是採用限制葡萄糖的生酮飲食,接著再偶而來一下脈衝法,目的是要殲滅少數從壓法中存活下來的癌細胞,作法是服用藥物來限制麩醯胺酸。因為麩醯胺酸也是身體所需的氨基酸之一,不能長期限制它,否則會傷害到正常細胞,只能短期限制。

 

【生酮飲食與蛋白質】

  • 蛋白質的攝取量必須降低到每日50~70克,大約是肌肉維修所需的最低量。換算公式是:
    每日蛋白質攝取量=1公克蛋白質/每公斤標準體重。(不能採用真實體重,要改採對應身高的標準體重。)

  • 根據Ron Rosedale的最新研究,一般人的蛋白質攝取量應該降到0.75克/每公斤淨瘦肉體重,甚至更低,這樣才能降低mTOR,讓身體進入維修狀態,減少糖尿病、癌症、肥胖的罹患機率。而已經罹患糖尿病或癌症者,必須攝取更低的蛋白質。
    糖尿病:低於0.6克/每公斤淨瘦肉體重
    癌症:低於0.45克/每公斤淨瘦肉體重

    (淨瘦肉體重=體重-體脂)

  • 過量蛋白質→激發mTORPKAIGF→抑制幹細胞生成、抑制自我吞噬作用。

  • Ron Rosedale指出:高蛋白質會升高IGF,而IGF與癌症、老化有關。

  • Ron Rosedale警告說:當今社會,限制蛋白質可能比限制醣類還重要!

  • Volek & Phinney版的生酮飲食蛋白質攝取量:

    Volek & Phinney版生酮飲食

     

    蛋白質

    最低量

    最高量

    每磅體重

    0.6

    1.0

    每公斤體重

    1.3

    2.2

    • 註:超過最高攝取量即脫離生酮狀態。

  • Marty Kendall認為,要攝取到足夠的營養素,蛋白質不能過低,至少要佔總卡的20%,相當於1.8克/每公斤淨瘦肉體重。下面圖表顯示不同蛋白質攝取量,會帶來不同的營養密度。
    左邊是營養素密度最高的食物。蛋白質攝取量超高,佔總卡的43%,這種飲食可以讓93%的營養素達到每日建議量。
    中間是【蛋白質/熱量】比值最低的食物。蛋白質攝取量最低,只佔總卡的1%,這時只有13%的營養素能達到每日建議量。
    右邊是胰島素上升指數最低的食物。蛋白質攝取量佔總卡的15%,大約30%的營養素可以達到每日建議量。

  • 也有研究指出,即使蛋白質達到2.2克/每日每公斤體重,仍然能維持生酮狀態。(https://sci-fit.net/carbs-protein-ketosis-research/#Does_a_high_protein_diet_prevent_ketosis)

  • 由於胺基酸會糖質新生,可能會影響生酮的機率,所以我們要摸清楚胺基酸與生酮飲食之間的關係。以下是根據胺基酸的生糖與生酮能力來分類的圖表:

     

    可轉換成葡萄糖的胺基酸

    二者皆可的胺基酸

    可產生酮體的胺基酸

    非必需胺基酸

    Alanine(丙胺酸)
    Arginine(精氨酸)
    Asparagine(天門冬醯胺)

    Aspartate(天門冬氨酸)

    Cysteine(半胱氨酸)

    Glutamate(谷氨酸)

    Glutamine(谷氨醯胺)

    Glycine(甘氨酸)

    Proline(脯氨酸)

    Serine(絲氨酸)

    Tyrosine(酪氨酸)

     

    必需胺基酸

    Histidine(组氨酸)

    Methionine(甲硫氨酸)

    Valine(纈氨酸)

    Isoleucine(異亮氨酸)

    Phenylalanine(苯丙氨酸)

    Tryptophan(色氨酸)

    Threonine(蘇氨酸)

    Leucine(白氨酸)

    Lysine(離胺酸)


  • 糖尿病專家Richard Bernstein表示,蛋白質轉換為葡萄糖的轉換率大約是36%。所以,蛋白質如果過剩太多,生酮的機率就會大大降低。(編者補充:也有觀點指出增加蛋白質並不會破壞生酮狀態。)

  • Nora Gedgaudas表示,身體對蛋白質的處理有限,尤其是缺乏油脂的情況下,因為油脂可以透過稀釋作用降低身體代謝蛋白質的毒性負擔,並提升身體對蛋白質的利用率。當總熱量的50%都來自沒甚麼油脂的蛋白質時,就會碰觸到身體代謝蛋白質的上限,必須為消化和代謝多餘的蛋白質付出代價,並且把自己置身於罹癌和加速老化的高風險之中。

  • Nora Gedgaudas表示,史前人類在生活環境嚴酷的舊石器時代,為了生存一定會選擇最肥美的肉品來填飽他們的胃和滋養大腦。如果飲食偏離了這條道路,吃進過量的蛋白質和低脂食品,就會惹禍上身,讓自己處於高氨血症(hyperammonemia)的狀態---即大量的氨堆積在體內。高氨血症會導致虛弱、腹瀉、嚴重乏力、心臟問題,甚至在短短數周內一命嗚呼!(編者補充:這就是所謂的【兔子飢餓症】。)

  • Steven Gundry指出,人類每天可以從腸道回收20克的蛋白質,所以事實上每天所需的蛋白質少得驚人!

  • 蛋白質的糖質新生作用是需求導向,有需求才會進行糖質新生,它不是攝取量導向,不是蛋白質攝取越多,糖質新生就會越多。須知,糖質新生作用是一個緩慢而穩定的過程,也就是說,它的生產速率很慢,很穩定,每日的總產量也相當有限。以前認為蛋白質的攝取量決定糖質新生的產量,事實上,蛋白質過少確實會減少糖質新生的產量,但是蛋白質過多並不會因此而增加糖質新生的產量,而且目前尚未發現任何堅固的證據來證實過量的蛋白質會轉換成葡萄糖。這麼一來,生酮飲食者是否就能攝取過量的蛋白質呢?答案是:對刻意追求高濃度酮體的人而言,仍然不適合吃過量的蛋白質,雖然過量蛋白質不會增加糖質新生的產量,但是蛋白質本身有抑制生酮的作用,還是會導致酮體減少。(請參考→http://www.ketotic.org/2012/08/if-you-eat-excess-protein-does-it-turn.htmlhttp://www.ketotic.org/2012/08/we-were-talking-about-gluconeogenesis.html)

  • 攝取過量蛋白質不會增加糖質新生的速率,但是會不會升高血糖呢?對非糖尿病與非生酮飲食的人來說,攝取過量蛋白質並不會升高血糖,但是對生酮飲食的人來說,攝取過量蛋白質會輕微升高血糖。參考下圖
    (紅色代表增加)

    飲食型態

    空腹

    攝取蛋白質後

     

    葡萄糖

    胰島素

    升糖素

    胰島素/升糖素

    葡萄糖

    胰島素

    升糖素

    胰島素/升糖素

    生酮飲食

    78

    8

    128

    1.7

    90

    15

    218

    1.83

    糖解飲食

    94

    17

    87

    4.35

    基準或更低

    28

    167

    8.2

    • 生酮飲食:產生酮體的飲食法。

    • 糖解飲食:分解葡萄糖的飲食法。

    • 胰島素/升糖素的比值是採pmole/L為單位計算的。

    • 胰島素換算,mIU/L → pmol/L,要乘以6.9444。

    • 升糖素換算,ng/L → pmol/L,要乘以0.2817。

    • 諸位套入公式換算後,會發現胰島素/升糖素的比值是近似值,與表格上的數值不同,那是因為表格內的數字都有正負誤差值,在此,為了畫面簡單化,容易對照比較,一律去掉正負誤差值,所以換算後才會產生近似值。例如:(8*6.9444)/(128*0.2817)=1.5407,不是表格內的1.7。

    • 生酮飲食者攝取蛋白質後,胰島素/升糖素的比值變化很小,因為胰島素與升糖素幾乎是等比例增加。

     

  • 也有研究指出酮體濃度與蛋白質攝取量無關。下圖統計了醣類與蛋白質的各種組合比例下的酮體濃度:(https://sci-fit.net/carbs-protein-ketosis-research/)
    當酮體達到高峰時(藍色),醣類是處於低谷(紅色)。相反地,當醣類達到高峰時(紅色),酮體是處於低谷(藍色)。但是蛋白質的攝取量越大(橘色),酮體的變化卻沒有正向或反向關係。結論是:酮體與醣類是反向關係,而酮體與蛋白質則是無關,也就是增加蛋白質的攝取量,並不會破壞生酮狀態。


 

Benjamin Bikman的研究

  • https://www.youtube.com/watch?v=z3fO5aTD6JU&fbclid=IwAR35FhXPVHUeqpCF9OWuIpNEZFfwYjljJVS9gb42Xw-k6gV20dc2riPQ_Z0

    通 則

     

    醣類

    蛋白質

    脂肪

    胰島素

    ↑↑↑

    ↑↑↑

    0

    升糖激素

    ↓↓↓

    ↑↑↑

    ↑↑↑

     

    通 則

     

    肌肉

    脂肪組織

    肝臟

    胰島素

    作用獨大

    作用強

    作用弱

    升糖激素

    無作用

    作用弱

    作用強

     

    低醣飲食

     

    醣類

    蛋白質

    脂肪

    胰島素

    ↑↑↑

    0

    升糖激素

    ↓↓↓

    ↑↑↑

    ↑↑↑

     

    低醣飲食

     

    肌肉

    脂肪組織

    肝臟

    醣類

    同化合成 同化合成 同化合成

    蛋白質

    同化合成 異化分解>同化合成 異化分解>同化合成

    脂肪

    異化分解 異化分解

     

  • 攝取蛋白質在不同血糖狀態下,會表現出不同的結果:
    高血糖狀態下,注入丙胺酸(可以轉換成葡萄的胺基酸)後,胰島素會大增,升糖激素會大降。(編者補充:血糖高時,血液能量已充足,蛋白質會刺激身體走向同化作用,也就是合成儲存模式。)
    低血糖(斷食)狀態下,注入丙胺酸後,胰島素不變,升糖激素會大增。斷食狀態下,人體為了保命,必須增加升糖激素來提領能源,不能增加胰島素來儲存能源。(編者補充:血糖很低時,血液能量不足,蛋白質會刺激身體走向異化作用,也就是分解燃燒模式。)

  • 胰島素/升糖激素的比例(I/G ratio),可以反映出哪一種代謝功能占優勢,同化合成作用或異化分解作用。
    比例高,同化合成作用主導。
    比例低,異化分解作用主導。
    比例高低是浮動的、變化的,不是一成不變。

  • 蛋白質對胰島素/升糖激素比例的影響,取決於肝臟需要製造多少葡萄糖。例如:標準美國飲食醣類豐富,不需要肝臟再把蛋白質轉換為葡萄醣,所以升糖激素不需要調高,於是胰島素/升糖激素比例就會較高。反之,低醣飲食需要需要肝臟把蛋白質轉換為葡萄醣,所以升糖激素需要調高來促進糖質新生作用,而升糖激素增加的結果,胰島素/升糖激素比例就會變低。

  • 斷食時,胰島素/升糖激素的比例值較低,大約是0.8。斷食的好處包括:
    1.胰島素敏感度增加。
    2.自噬作用增加,粒線體自噬作用也增加。
    3.脂肪分解作用增加。
    4.棕色脂肪組織活化。

  • 低醣飲食也可以享受斷食的諸多好處,而且不必像斷食一樣限制卡路里。

     

    24小時以上的斷食

    低醣飲食

    標準美式飲食

    胰島素/升糖激素比例

    ~ 0.8

    ~ 1.3

    ~ 4

    胰島素

    升糖激素

    同化/異化

    異化分解

    異化分解

    同化合成

    生化反應

    糖分解作用

    糖質新生

    脂肪分解作用

    酮體生成作用

    同左

    糖生成作用

    脂肪生成作用

    抑制酮體生成

    抑制自噬作用


     

     

    24小時以上的斷食

    低醣飲食

    標準美式飲食

     

    再給予蛋白質(1g/1kg體重)

    再給予蛋白質(1g/1kg體重)

    再給予蛋白質(1g/1kg體重)

    胰島素/升糖激素比例

    ~ 0.5

    ~ 1.3

    ~ 70

    胰島素

    ↑↑↑

    升糖激素

    ↑↑

    ↓↓↓

     

     

     

    高醣飲食投予蛋白質

    會大幅刺激胰島素分泌

 

 

【生酮飲食要注意營養素與電解質】

  • 生酮飲食會刻意壓低碳水化合物的攝取量,容易導致缺乏碳水化合物特有的營養素,所以生酮飲食最好搭配大量葉菜類蔬菜辛香料來補足營養素(前提是對這些食材沒有過敏)。同樣地,生酮飲食的蛋白質攝取量也會刻意壓低,所以也要注意必需胺基酸缺乏的問題。

  • 生酮飲食的脂肪量偏高,由於脂肪的代謝需要很多營養素的輔助,所以也要補足這些營養素,例如:B2、B3、生物素(B7)、肉鹼、鎂。

  • 生酮飲食→醣類攝取量減少→胰島素分泌減少→水排放增加→礦物質隨尿排出→鈉、鉀、鎂流失→電解質失衡→生酮不適症。所以生酮飲食要額外補充玫瑰鹽來補充礦物質,而且還要注意不能喝太多水,因為水喝越多,尿越多,礦物質流失也會越多。如果非喝不可,務必記得補充鹽巴。請參考→生酮不適症(Keto-flu)

  • Rabast的研究顯示,在開始的二周,低醣飲食組的鉀排泄量較高,但在四周後,低醣飲食組的鉀排泄量與高醣飲食組沒有差別。(https://www.ncbi.nlm.nih.gov/pubmed/7332312)

【生酮飲食 Vs 斷食】

  • 肝醣沒用完,肝臟是不會大量燃燒脂肪來製造酮體,而人體的肝醣儲備量大約12小時就用完了(有的版本是肝醣要24~36小時才會耗盡),所以每天只要空腹12~18小時或更長的時間,身體就會從燃燒葡萄糖的系統切換到燃燒脂肪的系統。舉例,如果每天的最後一餐是中午12點的午餐,那就要等到半夜12點身體才會開始大量燃燒脂肪製造酮體。以此類推,如果最後一餐是8點的晚餐,那就要等到隔天早上8點才會大量燃燒脂肪製造酮體。如果早上8點又吃了早餐,那就沒有機會大量燃燒脂肪製造酮體了,因此建議每天的【用餐時間】要集中在6~8個小時內完成,其他時間都要嚴格禁食。

  • Adam-Perrott的研究顯示,生酮飲食的肝醣耗盡時間約48小時,生酮速度比斷食慢一些,因為生酮飲食還是會吃進少量醣類,延後肝醣耗盡的時間。(編者補充:斷食最慢36小時燒完肝醣。)

  • 酮體一直都存在血液中,但是會隨著斷食或長時間運動而增加。據統計,經過一夜的斷食,酮體會供應身體2~6%的能量。經過3天的斷食,酮體會供應身體30~40%的能量。

【如何讓血糖降低到55~75mg/dL之間?】

  • 一般正常人的空腹血糖是維持在83 mg/dL左右,即使完全不吃碳水化合物也無法把血糖降到55~75 mg/dL之間,必須再配合限制卡路里與限制蛋白質攝取量,才能讓血糖降低到55~75 mg/dL之間。

  • 生酮研究者Dominic D’Agostino刻意用生酮飲食來製造極低的血糖濃度(25 mg/dL),一般人肯定會陷入昏迷狀態,但Dominic D’Agostino沒有,因為他的大腦能充分使用酮體當燃料。另外還有研究者創下更低的血糖紀錄,18 mg/dL。大家知道有這麼回事就好,不要去模仿,以免危險 !

【生酮飲食與皮質醇】

【生酮飲食與甲狀腺】

  • 生酮飲食會降低甲狀腺素的產量,因為胰島素有類似甲狀腺刺激素(TSH)的 功用,整個機制是:生酮飲食→胰島素下降→甲狀腺素減少。(https://www.youtube.com/watch?v=TzBkl52vxHkCris Masterjohn說;So insulin and leptin are both positive regulators of thyroid hormone, production, and conversion. And generally I do think there's probably a larger effect from thyroid production than peripheral conversion. I'm not too sure about that, but insulin does directly regulate thyroid. It has TSH-like effects on the thyroid gland. It doesn't replicate all of TSH's effects, but it does replicate a portion of them. So basically, more or less, have like TSH amplification with insulin. )

【酮體的代謝】

  • 酮體的來源有二:
    1.大宗來自脂肪酸的氧化。
    2.小宗來自胺基酸的轉換。

  • 脂肪酸經過氧化產生acetyl CoA,acetyl CoA再轉換成酮體。

  • 酮體可以當作燃料產生能量,未燃燒的酮體會從尿液中排出,不會儲存在體內。

  • 人體使用酮體的二大組織是:腦、肌肉(包括骨骼肌、平滑肌、心肌)。

  • 人體使用脂肪酸的二大組織是:肝臟、肌肉(包括骨骼肌、平滑肌、心肌)。

  • 當葡萄糖不足時,酮體恰好可以提供無法燃燒脂肪酸的組織當燃料,例如大腦。

  • 長時間斷食或飢荒狀態下,酮體可以提供大腦2/3的能源。

  • 肝臟只會製造酮體給其他組織使用,自己卻無法使用酮體,因為肝臟缺乏琥珀酰輔酶A轉移酵素(succinyl CoA transferase),無法將酮體的BHB與AcAc逆轉回acetyl CoA。(請參考→酮體的生成與分解)

  • 酮體分為左旋與右璇,右旋酮體是最乾淨的燃料,產生較少的活性氧化物質(ROS),有保護粒線體的作用,而粒線體健康,細胞核就不會突變,細胞也不會癌化。左旋酮體則比較像脂肪酸,產生較多的活性氧化物質。另外,左旋酮體還會消散質子動力梯度(proton-motive gradient),降低右璇酮體的能源效率。(編者補充:比起葡萄糖,游離脂肪酸與酮體都算是比較乾淨的燃料,產生較少的活性氧化物質。同理,動物性蛋白質的好處之一就是沒有夾雜太多的醣類,製造較少的活性氧化物質。比喻:右璇酮體=98汽油,左璇酮體=95汽油,游離脂肪酸=92汽油,葡萄糖=柴油。哈哈哈!)

  • 右旋酮體可以從中鏈脂肪酸的食物中獲得,例如:椰子油。

  • 編者補充:科學家已經可以利用化學方法去製造右旋酮體,但是人類的主要脂肪燃料是脂肪酸,不是酮體,酮體只是脂肪酸燃燒的產物之一,如果大量直接補充酮體,一定會改變脂肪燃燒的能源比例,到底會有啥後遺症不得而知。我們之所以提倡生酮飲食,是因為我們從斷食中看到了若干好處,我們才去模仿斷食而設計出生酮飲食,現在我們改變斷食特有的脂肪燃料比例,改變了以脂肪酸為主的燃燒方式,結果是好是壞,還有待科學家去追蹤!

  • 請參考→生酮或不生酮

  • 請參考→酮體的生成與分解

  • 請參考→Pyruvate的代謝

  • 請參考→PDH、PDC、PDP、PDK

  • 請參考→TCA循環

 

酮體的精準測量】

  • 酮體有三種:

  1. 乙酰乙酸鹽 (acetoacetate,簡稱AcAc)

  2. β-丁酸鹽-hydroxybutyrate,簡稱BHB,又稱為3-hydroxybutyrate或3-OH butyrate)

  3. 丙酮 (Acetone)

  • 測量是否進入生酮狀態最精準的方法是測量血液中β-丁酸鹽(BHB)的濃度,其次是測量呼吸中的丙酮(acetone)濃度,最不準確的是測量尿液中的乙酰乙酸鹽(AcAc)。通常進入生酮狀態一段時間後,乙酰乙酸鹽(AcAc)就會轉換成β-丁酸鹽(BHB),因此尿液中就檢測不出乙酰乙酸鹽(AcAc)了。

  • 用血糖值來判斷是否進入生酮狀態,是一種間接關係,不是直接證據。由於測量血液β-丁酸鹽(BHB)濃度與呼吸丙酮(acetone)濃度的機器尚未普遍,試紙也太貴,所以採用血糖值是一個不錯的變通方法。

  • 有些人即使採行超低醣飲食,體脂也大幅減少,但是尿液中還是不會出現酮體,因為這些人能進一步把酮體燃燒掉。

  • 越嚴格的生酮飲食,酮體的量不一定就越高,因為有些人善於代謝酮體,能進一步把酮體燃燒掉,所以血液中的酮體不會積留太多,尿液中也不會出現太多酮體。

  • Maria Emmerich指出,生酮飲食初期,身體會製造較多的酮體供身體使用,漸漸地,身體會搭建更多的粒線體來直接燃燒游離脂肪酸,於是酮體需求量會逐漸減少,檢測上,血酮濃度也會越來愈少,讓生酮者誤以為吃錯食物了!

【血酮濃度的問題】

  • 血酮濃度只能當參考,還要再深入測量酮體的產量與代謝量。

  • 酮體是脂肪代謝的中間產物,最後會變成二氧化碳與水。同樣地,葡萄糖是醣類代謝的中間產物,最後也會變成二氧化碳與水。

  • 血酮濃度只是代表酮體在血液的濃度,無法告訴我們明確的脂肪燃燒程度。血酮就好像倉庫的庫存,庫存的多寡,不是只看生產多少或銷售多少,而是看二者的互動。所以,血酮濃度有可能是以下情形的結果:
    1.生產多,燃燒多。
    2.生產多,燃燒少。
    3.生產少,燃燒多。
    4.生產少,燃燒少。

  • 酮體要進入細胞內需要單羧酸鹽轉運蛋白(monocarboxylic acid transporter)的運送,也就是說,空有酮體沒用,還要有轉運蛋白才行,如果酮體產量大,但是運輸蛋白不足,酮體就會滯留在血液中,造成高血酮症。

  • 運動可以增加轉運蛋白,提高人體利用酮體的能力。運動量越大,轉運蛋白也會越多。運動的人血酮會比不運動的人低,因為運動的人可以高效率地把血酮送進細胞使用,所以,血酮值並非精確的生酮指標

  • Maria Emmerich指出,生酮飲食初期,身體會製造較多的酮體供身體使用,漸漸地,身體會製造更多的粒線體來直接燃燒游離脂肪酸,於是酮體需求量會逐漸減少,檢測上,血酮濃度也會越來愈少,讓生酮者誤以為是吃錯食物了!

【酮體濃度分布圖】

  • 最佳濃度是:0.5~3.0 mmol/L。也就是所謂的營養性生酮狀態。

     

【胰島素 Vs 酮體】

  • 20世紀初,碳水化合物被稱為抗生酮因子”(the anti-ketogenic factor),因為葡萄糖會升高胰島素,胰島素一旦升高了,酮體的製造就會被迫關閉。三大營養素中,胰島素指數分別是:葡萄糖=100%,蛋白質=56%,脂肪=10%

  • 胰島素的作用是儲存,當胰島素濃度很高時,能源會輸入到細胞內儲存,反之,當胰島素很低時,能源會從細胞內輸出到血液。所以,生酮的流程是:血糖降低→胰島素降低→能源釋出的指令下達→肝臟分解肝醣,輸出葡萄糖,脂肪細胞釋出脂肪酸→肝醣庫存耗盡,葡萄糖缺乏補充的來源→脂肪酸成為主要的輸出燃料→脂肪酸送往肝臟分解成酮體→酮體大增。所以,
    生酮的3大前提:
    1.血糖降低
    2.胰島素降低
    3.肝醣減少

    反之,
    胰島素上升,酮體就下降,因為胰島素的指令是把營養分送進細胞內儲存,不是燃燒,所以,胰島素上升會關閉脂肪燃燒,最後導致酮體大幅下降。

【外源酮體 Vs 內源酮體】

  • 內源是指來自體內的東西,體內製造的。
    外源是指來自外面的東西,體外補充進來的。

  • 體脂產生的酮體是內源性酮體,外面補充進來的中鏈脂肪酸所產生的酮體是外源性酮體。內源酮體,身體可以控制得剛剛好,不會升高胰島素,相反地,外源酮體,會擠掉內源酮體的產量。如果外源酮體過量,導致血液總能量超標,身體也會分泌胰島素來把過剩的能源儲存起來,不會讓它白白浪費掉。

  • 胰島素升高→脂肪停止分解→酮體停產
    外源酮體過量→升高胰島素→儲存起來

  • Marty Kendall認為,降低血糖比提高血酮來得重要!(編者補充:降低胰島素更重要!)

  • Marty Kendall認為,追求治療性生酮狀態者,不能一味追求高濃度的酮體,還要管控血液總能量不能過高,也就是【血糖+血酮】的總量不能過高,過高還是會刺激胰島素分泌來儲存這些過剩能源(即使血糖沒有超過標準值也照樣升高胰島素)。另外,除了要追蹤血糖、血酮、血液總能量之外,還要注意葡萄糖/酮體的比值(GKI)。請參考→葡萄糖/酮體(GKI)。(編者補充:血液總能量應該也要包括游離脂肪酸。)

  • Marty Kendall指出,外源性酮體也會升高胰島素,升高幅度約為碳水化合物的一半。公式如下:
    胰島素負擔=醣類-纖維-0.75 x 果糖+0.56 x 蛋白質+0.5 x 外酮

  • 根據Marty Kendall的個人經驗,外酮並無助於運動表現,最佳表現反而出現在使用內酮的斷食期間。

  • 不同的外酮有不同的特性:

    外酮

     

    中鏈三酸甘油酯

    長鏈三酸甘油酯

    分解酵素(切斷甘油與脂肪酸的鍵結)

    胃酵素

    胰臟酵素

    運送到肝臟的路徑

    不經淋巴系統,直接送抵肝臟

    須經淋巴系統,再從大循環送抵肝臟

    肝臟分解脂肪酸的速度

【酸鹼中和】

  • 不管是內酮或外酮,酮酸畢竟還是酸性代謝物,所以實施低醣或生酮飲食或直接攝取外酮,最好補充足夠的鹼性物質,例如:蔬菜、鹼性礦物質補充劑(鎂、鈣、鈉、鉀、鋅),來中和這些酸性代謝物,以免身體庫存的鹼性礦物質被掏空了。

【吃藥與酮體】

  • 胰島素可以把血糖搬到肝臟儲存,如果吃藥傷到了肝臟,血糖就無法儲存在肝臟而會繼續積留在血液中,造成血糖升高,接著胰島素也跟著升高。一旦胰島素升高了,酮體的製造就會被迫關閉。

【醣類會打破斷食的生酮狀態】

  • 只要攝入7.5的葡萄糖,約2茶匙的糖或一小口的含糖飲料,生酮狀態特有的Beta-hydroxybutyrateacetoacetate就會迅速消失無蹤。

【生酮飲食的膽固醇問題】

【腎結石與生酮飲食】

  • 酮酸可能會增加腎結石的生成,尤其是有家族病史的人。

  • 檸檬酸鉀可以中和尿液的酸性,減少結石的沉積。(要經由醫師許可才能服用)

  • 大量喝水也有助於減少腎結石。

  • Annette Bosworth指出,結石的起因是胰島素過高,生酮飲食可以改善高胰島素,有助於溶解結石,但是在溶解過程中,結石可能會位移或脫落而產生疼痛,建議要繼續生酮飲食。(請參考→https://www.youtube.com/watch?v=mgLoC_dxjPI)

  • Robert Cywes認為,腎結石是高蛋白飲食造成的,不是低醣+低蛋白+高脂的生酮飲食。(https://www.youtube.com/watch?v=gQlE8CTipPI&t=2873s) (編者補充:從周遭的人身上也曾看到高醣低蛋白飲食的人罹患了腎結石,所以真正的原因可能還要再確認。)

【膽囊疾病與生酮飲食】

  • 膽囊的作用是儲存、濃縮膽汁,然後因應食物中的油脂而排放到十二指腸來乳化這些油脂,協助胰臟的酵素去分解脂肪。

  • 膽汁必須在膽囊裡經過濃縮後才能有效地執行乳化脂肪的任務。

  • 如果切除了膽囊,膽汁仍然會繼續分泌到十二指腸,但是濃度會較淡,數量也會較少,無法一次乳化大量油脂,所以,膽囊切除者必須限制每一次用餐的脂肪攝取量,否則就會有剩餘的脂肪無法乳化成小單位,導致一大坨油脂在小腸結成一團,阻礙其他食物的正常的吸收,最後整團通過大腸排出體外,這就是所謂的【油便】。

  • 膽囊切除者常常伴隨手術後遺症,例如:噁心、腹瀉,但大多數還是可以適應,不成問題。不過,還是建議無膽者在實施生酮飲食時,要慢慢追加脂肪攝取量,而且盡量攝取天然的高脂食物,例如:夏威夷果、酪梨、亞麻仁,或是把這些高脂食物拌入沙拉醬。千萬不要急著猛灌油!

  • 膽囊疾病者可以補充胰臟酵素(脂肪分解酶)、牛的膽汁、利膽草藥...等來幫助脂肪的消化。

  • 膽囊疾病者可以直接攝取中鏈脂肪酸(MCT、C8),跳過膽汁乳化的程序,直接穿透小腸黏膜,再經由肝門靜脈,送到肝臟轉化為酮體。

  • 朝鮮薊(Artichoke)可以增加膽汁分泌。(https://www.youtube.com/watch?v=Zm1gO4IKrFA&fbclid=IwAR0OQRiyvC-6fudrcECza1l3DNac48y9yjSFh76lvpRnPD4zHT-rG1gCanQ)

  • Eric Berg給膽汁呆滯的生酮飲食者的建議:https://www.youtube.com/watch?v=PXwHm-00BIg&feature=youtu.be&fbclid=IwAR3WZObsukt06JwSj2jMkFo_-SzQCVybFI7pb-CuVqB6cC4RXdbTtpqcoPc

  1. 搭配間歇性斷食,好讓膽汁有足夠時間濃縮,如果膽汁濃度太稀,乳化脂肪的效果就會變差。

  2. 攝取大量蔬菜來加速膽汁流通。蔬菜的選擇以苦味為佳,越苦越好!

  3. 補充膽鹽來分解膽固醇,降低膽固醇濃縮結晶成膽石的機率。(https://shop.drberg.com/gallbladder-formula-regular?WickedSource=YouTube&WickedID=gallbladderformula)

  4. 禁吃穀類與糖來降低胰島素,因為膽汁問題與胰島素過高有關。

  5. 不要攝取大量蛋白粉。

  6. 不要攝取大量堅果類。

 

膽囊疾病、膽結石

  • Eric Berg指出,膽結石是膽汁過少造成的。(膽汁可幫助分解膽固醇,減少膽固醇形成膽結石。)

  • 膽汁過少的可能原因:

  1. 雌激素過高,例如:避孕藥...等。

  2. 皮質醇過高,例如:壓力...等。

  3. 胰島素過高,例如:高醣飲食...等。

  4. 低脂飲食。(飽和脂肪與蛋白質最能刺激膽汁的釋出。)

  5. 脂肪肝。(肝功能受損)

  6. 胃酸過低或服用制酸劑。(胃酸可以刺激膽汁釋出) (胃酸過少的相關資料→胃食道逆流) (低鈉飲食→胃酸不足→膽汁不足→一籮筐問題)

  • 如何停止膽囊疼痛?

  1. 不要直接按壓膽囊處,改按壓左腹與膽囊對稱的點,約肋骨下緣1吋的地方。

  2. 減少糖與精製穀類。另外,食材也要避免【高碳水+高蛋白】或【高碳水+高脂】這二種組合。)

  3. 減少脂肪,尤其是某些堅果類,例如:核桃、花生。(編者補充:雖然低脂飲食容易造成膽結石,但是膽囊已經不舒服了,就暫時不要再攝取大量脂肪來刺激膽囊收縮了。)

  4. 避免頻繁用餐。(降低胰島素)

  5. 攝取羽衣甘藍(kale)或其他十字花科植物。(增強肝臟功能)

  6. 補充膽鹼(choline)。

  7. 補充純化的膽鹽(purified bile salts)。

  • 膽囊疾病的可能症狀:

  1. 腹部脹氣 (bloating)

  2. 打嗝 (burping)

  3. 噯氣 (belching)

  4. 便祕

  5. 右肩頸痛、右背痛、右偏頭痛、右臂痛、右手痛

  • 膽囊切除的後遺症:

  1. 膽汁不足

  2. 脂溶性維生素缺乏

  3. 脂肪吸收不良,例如:缺乏Omega-3。

  4. 胃炎

  5. 胃酸逆流

  6. 腹痛

  7. 脹氣

  8. 腹瀉 (沒有膽囊中途攔截膽汁,即使不用餐,膽汁還是會一直流入十二指腸 ,不斷刺激小腸黏膜,尤其是腸道已經沒有食物來吸附膽汁,膽汁的刺激性就會太強,引起保護性的腹瀉。)

  9. 便秘 (切除手術產生疤痕,阻塞膽汁,導致大腸缺乏足夠膽汁來潤滑)

  10. 肝臟結石

  • 膽囊切除的飲食建議:

  1. 適度脂肪 (不能過少,也不能過多)

  2. 適度蛋白質 (過多會升高胰島素)

  3. 低醣 (糖、澱粉類)

  4. 大量葉菜類蔬菜,越苦越好!

  5. 蘋果西打醋

  6. 發酵的蔬菜 (增加益生菌)

  7. 不要吃太撐 (擠壓到膽汁通道)

 

【尿酸與生酮飲食】

  • 蛋白質分解會產生普林(purine),普林分解會產生尿酸,而痛風發生處的沉澱物正是尿酸的結晶,所以大家都誤認為高蛋白質食物容易導致痛風,事實上,1984Irving Fox早就發現低普林飲食對痛風是無效的 !

  • 素食可以降低血液中10%的尿酸濃度,但是影響不大,不足以解決痛風的問題。更震驚的是,攝取額外的蛋白質反而可以提高腎臟排放尿酸的量,進一步降低血液中的尿酸濃度。

  • 一般人害怕生酮飲食的原因之一就是蛋白質含量太高,撇開蛋白質與痛風的低關聯性不說,真正的生酮飲食是超低醣+中低蛋白+高脂肪的飲食。它是高脂飲食,並不是高蛋白飲食。

  • 雖然生酮飲食不是高蛋白飲食,但是通常第一次進入生酮狀態的人,尿酸還是會有升高的現象,只是不用擔心,4~8周後就會恢復正常。

  • 酮體與尿酸會互相競爭分解酵素,如果酮體競爭勝利,尿酸就無法完全分解排出。

  • 尿酸的追蹤方向:

  1. 外酮是否攝取太多?(內酮的產量會剛剛好,外酮的產量容易過量,搶走分解尿酸的酵素。)

  2. 果糖是否攝取過多?(天然食物也可能含有果糖,例如:蔗糖含有50%的果糖,蜂蜜含有55%的果糖,高果糖玉米糖漿含有65%的果糖,龍舌蘭糖漿含有90%的果糖。)
    (a)細菌會分解果糖,產生尿酸。
    (b)果糖的其中一個代謝產物是乳酸,乳酸也會跟尿酸競爭排泄途徑,導致尿酸積留體內,形成痛風。
    (c)果糖會增加ATP的分解,然後經過一系列轉換,最後產生尿酸。(ATP→ADP→AMP→IMP→Inosine→Hypoxanthine→Xanthine→Uric acid)

  3. 酒精是否攝取過多?

  • Maria Emmerich指出,胰島素抗阻才是痛風的原因,因為胰島素抗阻會減少尿酸的排放,導致血液尿酸增加。同時,胰島素抗阻也會減少鈉的排放,導致血壓升高。

  • Nora Gedgaudas指出,適當補充檸檬酸鉀(每日99毫克)可以幫助身體排出尿酸。請參考→尿酸

  • Paul Saladino的痛風觀點:(https://www.youtube.com/watch?v=fN7gXBRqUHI&t=435s)
    1.痛風是尿酸排泄不足造成的,不是尿酸太多造成的。

    2.尿酸的來源:自身製造占多數,膳食取得占少數。
    3.胰島素抗阻才是痛風的主因,因為胰島素過高會降低尿酸的排泄。
    4.胰島素抗阻的成因:攝取太多醣類(澱粉、果糖)、發炎(omega-6脂肪酸)。
    5.酒精也會降低尿酸的排泄。

  • Ken Berry指出,身體分解ATP、GTP、DNA或RNA時就會產生代謝物--普林(purine)。這些是屬於身體自產的【內源性普林】,而從食物中獲得的普林則稱為【外源性普林】。Ken Berry提出五點質疑:(https://www.youtube.com/watch?v=95mhn0ry2LY)
    1.內源性普林的產量是外源性普林的5~10幾倍,所以把痛風的原因大宗歸咎於高普林食物是不合理的。
    2.高尿酸患者未必都罹患痛風。
    3.在健康的關節囊裡也能抽取出尿酸結晶,但是這些尿酸結晶並沒有引發痛風。
    4.身體可以利用尿酸作為抗氧化劑。
    5.腎臟是排泄尿酸的地方,但是腎臟會回收50%的尿酸,不是全部都排掉。如果尿酸是壞東西,腎臟應該不會再把它回收。

尿酸

  • 尿酸的化學名是:2,6,8 trioxypurine。化學式是:C5H4N4O3。

  • 尿酸的外在來源有三:
    1.果糖
    2.酒精
    3.
    普林(purines)

  • 尿酸是肝臟製造的,其中,65~75%是由腎臟排出體外,25~35%由大腸排出。

  • 草酸、乳酸、酮體(AcAc與BHB)與尿酸之間會互相競爭代謝途徑,如果草酸、乳酸、酮體過多,尿酸的排泄就會被抑制而導致尿酸升高。

  • 尿酸是普林代謝的終產物,人類由於尿酸酶活性不足,導致人類比其他哺乳動物擁有較高的尿酸濃度。

  • 尿酸的分子結構很像咖啡因,具有振奮的作用。

  • 由於尿酸具有雙鍵,所以尿酸具有很好的抗氧化能力。事實上,血漿中大約2/3的抗氧化力是由尿酸提供的。

  • 生酮飲食增加尿酸其實是增加抗氧化力。

  • 尿酸的抗氧化能力比維生素C還強。

  • 尿酸在血漿中會表現抗氧化劑(anti-oxidant)的特性,但是在細胞內卻表現親氧化劑(pro-oxidant)的特性。

  • 飲食、肥胖、代謝症候群都會影響尿酸的濃度,目前還不清楚尿酸的抗氧化能力在這些疾病中扮演的角色。

  • 高尿酸的定義:
    男性高於7mg/dL
    女性高於6mg/dL

  • 高尿酸常發生於70歲以上的男性、非裔美國人、腎臟病患、喝酒者。

  • 男性比較容易受到食物的影響而引發痛風。

  • 尿酸會隨著年紀增長而增加。

  • 98%的尿酸是以單價的鈉鹽型式(尿酸鹽)循環於血液中。單純游離態的尿酸,水溶性很差,血溶性也很差,照理說,尿酸在血液中的濃度只要達到6.4mg/dL就會飽和,事實上並非如此,因為尿酸會跟蛋白質結合,一旦結合了,它的血溶性就會提高70%以上,所以尿酸的濃度才會出現6.4mg/dL以上的高濃度。

  • 高濃度尿酸致病的原因是因為尿酸在細胞外的環境中溶解度極低,導致尿酸結晶沉澱,產生類似抗原的效應,啟動一連串的發炎反應。常見的發炎部位是腳拇趾關節。

  • 高尿酸可以做為一些疾病風險的評估指標,例如:腎臟病、糖尿病、心血管疾病、發炎,甚至也可以當作死亡風險的評估指標。

  • 高尿酸會增加16%的全因死亡風險,增加39%的心血疾病風險。

  • 一般歸納,尿酸急性上升是保護因素,慢性上升則是疾病風險因素。

  • 尿酸與長壽、智商有正向關聯。

  • 尿酸與代謝症候群息息相關。據統計,尿酸過高者有62.8%罹患代謝症候群,尿酸正常者只有25.4%罹患代謝症候群。

  • 尿酸可以保護神經免於麩胺酸鹽毒性造成的神經退化。

  • 新發現:根據David Perlmutter的新書《Drop Acid》,即使尿酸的血液濃度還落在所謂的正常範圍內,慢性升高的尿酸濃度還是跟很多疾病息息相關,例如:肥胖、心血管疾病、糖尿病、胰島素抗阻、高血壓、 血脂異常、脂肪肝、中風、神經失調、認知能力下降、早死....等。

  • 尿酸會增加體內脂肪的產量,造成腰圍擴大,即使沒有過重的問題,也可以在肝臟看到脂肪的堆積。


【與高尿酸相關的疾病】

  1. 痛風性關節炎 (尿酸高於7mg/dL,罹患痛風的機率較高。)

  2. 代謝症候群 (高血壓、高血糖、高血脂、肥胖)

  3. 心血管疾病

  4. 糖尿病

  5. 腎臟病 (包括腎結石、腎臟移植、洗腎)

  6. 貧血 (尿酸會跟鐵結合)

  7. 副甲狀腺素過高

  8. 骨折

  9. 尼氏乃罕症候群 (Lesch-Nyhan Syndrome)

  10. 唐氏症

  11. 勃起障礙

  12. 牛皮癬

  13. 骨性關節炎

  14. 白血症 (leukemia)、白細胞增多症 (leukocytosis)、萎縮症 (dystrophy)

【與低尿酸相關的疾病】

  1. 多發性硬化症

  2. 巴金森

  3. 阿茲海默症

  4. 亨丁頓舞蹈症


【增加尿酸的因素】

  1. 高蛋白飲食 (肉類、海鮮) (編者補充:高普林食物只能升高1~2mg/dL的尿酸濃度,不一定是促成痛風發作的主因。)

  2. 肌苷 (Inosine,例如:肝臟、魚類...等。)

  3. 甲基黃嘌呤 (methylxanthine)

  4. 果糖,包括會代謝成果糖的水果、山梨糖醇(Sorbitol)、蔗糖。

  5. 酒精,尤其是啤酒。

  6. 肥胖

  7. Niacin

  8. 利尿劑

  9. 生酮飲食

  10. 乳酸 (Lactate)

  11. 乳酸血症 (Lactic acidosis) (編者補充:葡萄糖進行無氧糖解作用會產生乳酸)

  12. 腎臟病

  13. 高血壓

  14. 甲狀腺低下

  15. 基因

  16. 性荷爾蒙

  17. 年紀

  18. 腫瘤溶解症候群 (Tumor lysis syndrome)

  19. 癌症化療 (cytotoxic chemotherapy)

  20. 慢性鉛中毒

  21. 免疫抑制劑

  22. 高鈉飲食

  23. 藥物 (ciclosporin、ethambutol、pyrazinamide、cytotoxic chemotherapy)

【減少尿酸的因素 】

  1. 奶製品與鈣 (乳清蛋白與酪蛋白的作用)

  2. 高劑量維生素C

  3. 雌激素 (難怪男性痛風機率較高)

  4. 藥物 (benzbromazone、losartan、probenecid、sulfinpyrazon)

  5. 咖啡 (綠原酸的作用)

  6. 低卡飲食 (改善胰島素抗阻)


【參考圖表】





【參考資料】

 

【乳酸與酮體】

  • BHB與乳酸使用相同的運輸蛋白,二者互相競爭,因此,提高BHB可以搶走運輸蛋白,不讓乳酸進入細胞內。

【酒精與酮體】

  • 酒精的其中一個代謝途徑是產生酮體。

  • 酒精(乙醇)→乙醛→乙酸→乙醯輔酶A→酮體→酒精性酮酸中毒 (其他的酮酸中毒還包括:糖尿病酮酸中毒、水楊酸酮酸中毒...等。)

  • 生酮飲食者,如果睡前喝酒,隔天起床後酮體會增加,造成誤判。(請參考→Alcoholic Ketosis)

Alcoholic Ketosis

Alcoholic ketosis, or alcoholic ketoacidosis (AKA), can technically be classified as a variation of nutritional ketosis since it occurs due to a dietary intervention. Like its name implies, this form of ketosis is a result of alcohol consumption and causes an acidic internal environment due to the drastic increase in ketone bodies. AKA can occur in those who frequently drink or those who are malnourished and drinking alcohol. Symptoms of alcoholic ketosis, depending on the severity, can include nausea and vomiting, fatigue, altered breathing, and abdominal pain. AKA typically occurs the day after drinking and is characterized by increased ketone production in conjunction with a mild elevation in blood glucose levels, making it much different than other variations of ketosis. Ketone bodies B-hydroxybutyrate (BHB) and acetoacetate (AcAc) are formed via alcohol metabolism in the liver. Due to the redox state that accompanies AKA, BHB tends to be the ketone body that is elevated to the greatest extent. Additionally, due to the dehydrated state that typically accompanies alcohol consumption, the kidneys fail to excrete these extra ketones. Under normal conditions, our bodies may shut down ketone production when they become elevated to dangerously high levels. However, during AKA, hormonal changes (cortisol and catecholamines) occur that promote further lipolysis, which provides more substrate for additional ketone production. An additional change that accompanies alcohol consumption is suppressed insulin secretion, which provides an additional state in which ketones can be produced.

There are several treatment options for AKA including intravenous fluid and vitamin administration. These fluids typically contain glucose as an attempt to increase insulin secretion. This form of ketosis is not recognized as safe and is not a recommended variation of ketosis.

 

 

【能源燃燒的先後順序】--Marty Kendall

  1. 酒精

  2. 外酮

  3. 多餘的蛋白質

  4. 葡萄糖

  5. 脂肪

  • 版本1

    圖表的中文翻譯

    飲食輸入源

    酒精

    外酮

    蛋白質

    碳水化合物

    脂肪

    氧化順序

    1

    2

    3

    4

    5

    儲存系統

    血液

    血漿、其他組織

    血液(葡萄糖)、肝醣

    脂肪組織

    儲存量

    20卡而已

    360~480卡

    1200~2000卡

    無限

    飯後血糖的表現

    如上圖

    如上圖

    如上圖

    如上圖

    如上圖

    飯後4~6小時所釋出的熱量

    15%

    3%

    25%

    8%

    3%

    • 飯後釋出的熱量是指食物的能量一部份會轉換成熱量釋放出來,換句話說,釋出熱量越多,儲存起來的熱量就越少。這也是蛋白質不易增胖的原因,因為25%都轉成熱量散發掉了。

  • 以上次序是列出每個時期的主要能源,事實上每個時期不會只燃燒一種燃料,而是多種燃料同時燃燒,差別是多或寡而已。大家要善用這個次序,例如:喝酒與外酮都會卡位,搶走體脂的燃燒機會。

  • 酒精會增加3倍的雌激素(estrogen),降低睪固酮(testosterone)達24小時之久。

  • 外酮是屬於優先燃燒的能源,減肥者不宜多喝防彈咖啡。(外酮=C8、MCT...。)

  • Craig Emmerich的減肥建議是:
    零酒精+零外酮+僅足夠保留肌肉所需的蛋白質+很少或零醣類+30~40克脂肪來幫助吸收脂溶性維生素與製造荷爾蒙。這樣身體的主要能源就會落在體脂。

  • 每次進食,胰島素都會分泌,接著身體就會先關閉燃燒庫存的能源,然後按照能源燃燒優先次序去燃燒新進的能源,等到一切就位了,該燒的依序燒完了,沒燒完剩下的也都儲存好了,最後才開始把庫存的能源搬出來燒。所以要減肥,必須設法降低胰島素,重啟燃脂模式,讓身體有機會燃燒到體脂。要降低胰島素或不讓胰島素上升太多的作法是:

  1. 選擇低胰島素指數的食物,尤其是要減少醣類。

  2. 限制總卡。

  3. 延長空腹的時間,甚至斷食更好。

  • 根據能源燃燒次序,Maria Emmerich建議以下的配套措施來增加燃燒體脂的機會:

  1. 不要喝酒。

  2. 不要喝外酮。(防彈咖啡)

  3. 吃適量的蛋白質,足夠身體維修即可。(編者補充:其實,高蛋白質食物的減肥效果最強,理由是:1.蛋白質的飽食感最強,很難吃過量。即使過量,也會比醣類或脂肪優先燃燒,不會積存太多在血液中,導致身體把這些過剩能量轉存為體脂。2.蛋白質燃燒時會釋出25%的能量,只剩75%能被身體利用,有利於總卡的減少。)

  4. 醣類盡量減少。

  5. 吃足夠讓荷爾蒙高興的脂肪量。(Eat just enough fat to keep your hormone happy.)

  • 版本2

    MPS=肌肉蛋白質合成。

 

【奶製品與生酮飲食】

  • 牛奶與軟起司含有太高的乳糖,不適合納入生酮飲食。

  • 硬起司含太多蛋白質,不但會升高胰島素,而且會增加IGF-1,促進癌細胞生長。

  • 硬起司只能當點綴品,例如:沙拉只能灑8克的帕馬森起司,而且最好再淋一些油來提高脂肪的比例。

  • 高脂的乳製品,例如奶油與鮮奶油,蛋白質含量較少,而且還可以進一步提煉成蛋白質幾乎等於零的酥油。但是要注意的是這些高脂乳製品,不管是來自工廠飼養的牛或是有機牧場的快樂牛,都含有雌激素的代謝物。這對罹患荷爾蒙敏感型腫瘤的患者是相當不利的!

  • 克菲爾酸奶(kefir)或一般優格(yogurt)含有較多的醣類,必須擠乾濾掉乳清,而且只能少量攝取。

【生酮飲食與肌肉生長】

  • 傳統觀念認為,肌肉的生長不可或缺的營養素是肝醣與胺基酸,所以必須攝取澱粉與蛋白質。但是根據Jacob Wilson的最新研究顯示,有或沒有醣類,重量訓練都會長肌肉。換句話說,有無醣類,蛋白質一樣能合成肌肉。

  • 研究發現,經過6周的低醣生酮飲食(5%醣類),肌肉的肝醣量不變,沒有減少。原理是:胺基酸中的丙胺酸(alanine)可以快速轉換成葡萄糖(糖質新生),再合成為肝醣提供肌肉使用。

  • BHB可以促進肌肉蛋白質合成,並降低白胺酸(Leucine)分解。白胺酸是負責觸發肌肉蛋白質合成並且促使肌肉生長的主要胺基酸,因此預防其分解有助於保存和增加肌肉質量。(https://www.ncbi.nlm.nih.gov/pubmed/3392207)

  • BHB可以抑制肌肉蛋白質分解(MPB)。(https://www.sciencedirect.com/science/article/pii/S1550413116304387)

【生酮飲食與肌肉流失】

  • 生酮飲食不會犧牲肌肉來進行糖質新生。

  • 肌肉的建構需要胺基酸,而胺基酸之一的丙胺酸(alanine)恰好是比較少用的肌肉建材,因此,丙胺酸可以挪用來糖質新生製造成葡萄糖,不需要分解肌肉來支援糖質新生。

  • 實驗分成二組,一組是一周7天都實施生酮飲食,另一組是周一到週五實施生酮飲食,周末2天補充澱粉。結果發現,二組體重都有減輕,不同的是,一周7天生酮飲食所減的體重是體脂,肌肉沒有減少,而一周5天生酮飲食所減的體重是肌肉居多,體脂只減少一點點。結論是:生酮飲食不會犧牲肌肉來進行糖質新生,提高醣類反而會抑制生酮適應狀態,最後導致肌肉流失。

  • 目前各項實驗的結論傾向:極低醣飲食只要攝取足的蛋白質就不會造成肌肉流失的問題。

  • 根據Mariam Kalamian的說法,生酮飲食(仿斷食)的頭幾天確實會分解肌肉的蛋白質來糖質新生,幾天後就改由三酸甘油酯分解成甘油來支援糖質新生。所以,不要為了支援糖質新生而補充大量蛋白質(編者補充:夠用就好),過剩的蛋白質還是會轉換成葡萄糖,導致身體一直依賴葡萄糖而無法進入生酮狀態。(《Keto for Cancer》p.23)

  • Maria Emmerich認為,偶而補碳循環性補碳會造成身體脫離生酮狀態,能源系統由仰賴脂肪退轉回仰賴醣類,如果補碳時醣類又供應不足,身體就會分解蛋白質(肌肉)來填缺,導致肌肉流失。這是補碳者需要注意的地方!

  • 編者補充:由於長期的飲食習慣,身體的能源燃燒系統已經固定模式了,如果突然間改變飲食,很可能會出現能量缺口,導致能量赤字,例如:平時以燃燒葡萄糖為主的飲食突然改變成燃燒脂肪為主的生酮飲食,短時間內燃燒脂肪的酵素與粒線體可能會來不及增產,導致身體既無足夠的葡萄糖來當燃料,又無法火力全開地燃燒脂肪。這時候,身體可能會分解肌肉的蛋白質來支援,如果蛋白質的糖質新生夠強,能源缺口就能填滿,頂多是犧牲肌肉而已,但是如果糖質新生太弱,能源缺口就會一直存在,身體也會被迫調降新陳代謝率來降低能源支出,於是產生了一些代謝率過低的症狀。

【生酮飲食的運動表現】

  • 生酮飲食的初期幾周內不建議做劇烈運動,最好是等身體能有效率使用酮體當燃料後才做劇烈運動。

  • 實施生酮飲食一周後,運動表現會較差一些,大約6周(或更長的時間)以後,才會慢慢恢復原來的水平,所以,一般都認為生酮適應期是幾周到幾月的時間,但是,從優秀運動員的實驗中發現,生酮適應一直都在進行,有的甚至超過一年。

  • 生酮適應後的生理變化是:粒線體數目增加、血酮增加、酮體的吸收與利用能力增強(細胞層級)。(https://www.ncbi.nlm.nih.gov/pubmed/7000826)

  • 運動會產生很多活性氧化物質,葡萄糖代謝也會產生很多活性氧化物質,二者結合更嚴重,也就是說,高醣飲食+劇烈運動,產生最多的活性氧化物質。(活性氧化物質=Reactive oxygen species,是一種自由基,會破壞細胞膜、DNA...等。)

  • Steve Phinny提供了三個技巧給耐力運動員:

  1. 給自己2~4周的時間去適應生酮飲食。

  2. 每天補充3~5克的鈉和2~3克的鉀來保持適當的電解質平衡。

  3. 蛋白質攝取量要個人化,讓生酮狀態與體能最佳化。

【嬰兒與生酮】

  • 嬰兒出生時是處於生酮狀態,他們使用酮體的速率是成人的5~40倍。

  • Jeff Volek認為,長大後燃脂能力的減弱是因為採用了高醣飲食,是人為的改變,不是人類長大後就應該採用非生酮飲食。

  • 懷孕初期,胎兒脂肪是快速增加的,懷孕後期,胎兒脂肪是快速減少的。

母乳

  • 母乳是高脂的,脂肪佔50%以上,其中包括了豐富的飽和脂肪與膽固醇。

    熱量百分比(千卡) 母乳 配方奶
    %蛋白質 6 9
    %脂肪 52 48
    %碳水化合物 42 42
  • 母乳的高脂是專門提供大腦快速發育用的。

  • 母乳與羊乳的卡路里比例很類似:

  • 新生兒是處於生酮狀態,Beta-hydroxybutyrate的濃度高達2~3mmol/L,新生兒的大腦會消耗總能源的60~70%(大人約消耗20%),而且一半是使用Beta-hydroxybutyrate,所以母乳也必須是高脂食物,否則無法製造出足夠的酮體給新生兒。

  • 母乳含有大量三酸甘油酯與蛋白質,乳糖卻很少。出生後2~3天,母乳的乳糖才逐漸增加,結束生酮狀態。

【生酮的原理】

  • 生酮狀態的前提是缺乏葡萄糖(不是靠增加膳食脂肪),身體被迫代謝脂肪來當能量。要打造葡萄糖缺乏的環境,有3種方法:

    1.直接方式:限制醣類。

    2.間接方式:減少蛋白質。因為過多的蛋白質會轉換成葡萄糖,無法製造缺乏葡萄糖的前提條件。(編者補充:也有研究指出蛋白質攝取量即使高達2.2克/每日每公斤體重,仍然能維持生酮狀態。https://sci-fit.net/carbs-protein-ketosis-research/?fbclid=IwAR2mgq1evFeLJ7bBroIPLtq-0hqDcVI-LYrpe_iqJBtzJjlG_tK9mzIsPjM)

    3.少食或斷食:斷食經過一段時間後,體內的葡萄糖、肝醣就會用光,於是身體被迫分解脂肪成酮體來當主要能源 。

  • 當身體沒有足夠的醣類與蛋白質來提供草醯乙酸(OAA)時,草醯乙酸就無法推動乙醯輔酶A(Acetyl CoA)進入克式循環(Krebs Cycle)而改走生酮路線,最後轉換成酮體(Ketones)。(圖形:改走左邊的路線,從紫色區塊進入黃色區塊。)

【解析南雲吉則的一日一餐】

  • 日本醫師南雲吉則是利用【一日一餐+少食】來進入生酮狀態,他不是採用低醣、低蛋白、高脂的飲食法。(請參考→各種生酮的方法)

  • 南雲吉則的具體做法是:每天只吃晚餐,食量超少,通常是一小碟菜、一小碗湯,再加上少量主食,吃完馬上睡覺(他說馬上睡覺可以讓食物轉換成脂肪)。由於食量極少,身體會盡量儲存脂肪,所以第二天起床後,他就靠燃燒儲存的脂肪度日。

  • 南雲吉則是極低卡飲食,但仍能維持健康。再參照其他少食者、食氣者的例子,讓人不禁懷疑人類所需的卡路里可能比專家們建議的還要少很多!

【生酮與新陳代謝】

  • 長期低卡飲食會讓身體進入飢餓模式而調低新陳代謝率,但是正確的生酮飲食並不會讓身體進入飢餓模式,也不會導致新陳代謝率下降。(編者補充:理論上,要補足能量缺口,身體才不會被迫調降代謝率,但是低代謝率是否等於不健康?我們在現實生活中常常看到很多長期低卡的人身體一直都很健康,為什麼?我猜想,人體需要的卡路里可能比我們想像的還要少很多,其中牽涉的因素可能包括:腸道細菌提供了部分能源、消化吸收率大幅提升.....等。另外,我們也從書本上得知一些不食的人,或是所謂食氣的人,這些人的存在讓我們不禁思考人類是否還有食物以外的其他能源模式。)

【總結】

  • 可以測試早上的空腹血糖,如果落在55~75之間,就代表你已經進入生酮狀態。這時,你不是靠很高的血糖來維生,你大宗是靠酮體(脂肪)維生,你只需要生產少量的葡葡糖來供應少數依賴靠葡萄糖維生的細胞(粒線體數目很少或完全缺乏的細胞),例如:紅血球、白血球、眼角膜、視網膜、水晶體、睪丸、腎臟內皮細胞。

  • 如果是高於75,但是落於75~83之間,你也可能處於生酮狀態,只是不太確定。正常人的血糖是83,所以空腹血糖高於83者,確定已經脫離生酮狀態了,必須再調整飲食。大致上都是在調整蛋白質的量,這是生酮飲食的盲區,因為多餘的蛋白質會轉成葡萄糖。另外一個盲區是總卡路里,最常見的是脂肪攝取量過高。因為即使醣類與蛋白質都控制很好,但是脂肪攝取過量,造成總卡路里過高(請參考→血液總熱量),也是會脫離生酮狀態。為什麼?當血液總能量過多時,身體會設法把過剩能量儲存起來,於是分泌胰島素來把營養素送進細胞,而胰島素與酮體是呈相反關係,胰島素上升,酮體就下降,所以整個流程是:總能量過高→胰島素上升→關閉脂肪燃燒→酮體下降。

  • 編者個人的總結是,生酮飲食的輸入條件(input)5個,如果正確輸入,就能得到正確輸出(output)

  1. 超低醣類,20克以下。這是最重要的關鍵!(編者補充:1.穀類、水果、根莖類都禁吃,只吃葉菜類與香料。2.有些版本是主張醣類要控制在50克以下。3.醣類在0~80克/每日,都有可能保持酮態,因人而異!比較保險的醣類範圍是20~60克/每日。)

  2. 低蛋白 (1公克蛋白質/每日每公斤體重) (編者補充:蛋白質的多寡,目前專家的意見仍然很分歧。)

  3. 高脂 (要占總卡路里的80%以上)中短鏈脂肪酸尤佳,例如:奶油、椰子油、C8。這是輔助方法,幫助身體對抗飢餓,順利度過時應期。

  4. 控制總卡路里。(編者補充:這是最後決勝點!要靠自己去抓出大概!)

  5. 縮小進食窗口,6小時之內完成所有餐飲,其他時間禁食。(編者補充:我個人的作法是一日一餐,如果你非吃2餐不可,我的建議是過午不食。)

 

各種生酮的方法

以下的計算時間是:每一天

  1. 20克醣類或更少。

  2. 斷食超過24小時。

  3. 20克醣類或更少+零脂肪

  4. 20克醣類或更少+很多脂肪

  5. 只吃醣類,但總卡要低於400卡。

  6. 只吃蛋白質

  7. 任意吃,但瘋狂運動。(耗盡肝醣存量)

  • 禁食數小時,時程視年齡大小而定,請參考下圖酮體濃度與禁食時間的關係圖:
    年紀越大,酮體生成速度越慢。
    新生兒幾乎都處於生酮狀態,平時血酮濃度就已經是0.5 mmol/L,禁食2小時後,血酮濃度更爬升到2.0mmol/L。
    6~8歲的小孩,只要5~6小時不進食,血酮濃度就能達到0.5 mmol/L。
    成年人的血酮濃度要達到0.5 mmol/L,必須禁食14小時。
    本圖顯示,不一定要靠攝取大量膳食脂肪或外酮就能達到生酮狀態。

  • 資料來源:《Keto.》p.79~80

 

Robert Cywes的生酮步驟

  1. 醣類盡量減少到零,以零醣為目標,把生產葡萄糖的任務交給蛋白質的糖質新生。

  2. 增加脂肪的攝取量,蛋白質常常伴隨脂肪食物,不用特別擔心蛋白質太少的問題。

  3. 增加鹽巴的攝取量。補充鹽巴可以解決大多數的生酮不適症。

  4. 分批進食。把食物分成很多小等分,每次用小盤盛裝一點點,吃完後如果還感到飢餓,再去盛裝一點點。

  5. 充分接收大腦的飽食信號。進食時間不能短於15~20分鐘,因為脂肪細胞接收到膳食脂肪後會分泌瘦體素,大腦接收了瘦體素後會下達飽食信號,這整個過程需要15~20分鐘的時間。所以,如果很快就吃完飯,我們會無法收到大腦的飽食信號,等到收到食,我們已經攝取過量了。

  6. 間歇性斷食。如果生酮飲食做得好,油脂攝取量也足夠,就可以長時間沒有飢餓感,很自然地做出間歇性斷食,而不是刻意去實施間歇性斷食。

  7. 搭建新橋:大腦的注意力只能維持20~30分鐘,之後就會感到疲倦,無法集中注意力。這時必須搭一座橋樑讓大腦獲得休息、鬆懈或安慰犒賞,然後再銜接到下一波的腦力集中時段。搭橋的方法有很多,很多人會利用零食來搭橋犒賞大腦,久而久之,就養成了吃零食的習慣,造成卡路里過剩的後遺症。針對這個問題,我們可以用一些不用腦力的小活動,例如:散步、遛狗,或無卡路里的食物,例如:茶、咖啡,來取代零食。通常,建立一個新習慣需要21天的時間,所以,新習慣只要持續21天,就能置換舊習慣。

 

【生酮飲食治病】

  • 生酮飲食可以改善下列疾病:
    糖尿病
    癌症
    帕金森氏症
    癲癇
    阿茲海默症
    創傷性腦吮商
    克隆氏症
    多發性硬化症
    自閉症
    抑鬱、焦慮
    躁鬱症
    偏頭痛、頭痛
    創傷後壓力症候群(PTSD)
    精神分裂症
    亨丁頓氏舞蹈症
    多囊性卵巢症候群(PCOS)
    肌萎縮性脊髓側索硬化症(ALS)/魯蓋瑞氏症
    注意力不族過動症(ADHD)
    Glut1缺陷症候群
    肝醣儲積症(GSD)
    發炎和傷口
    老化與長壽

  • 以上疾病的生酮對治,內容繁多,請直接參考→《生酮聖經飲食》


補充資料

 

答覆網友

  • 生酮飲食的關鍵是減少醣類,不是增加脂肪攝取量,只要醣類減少,身體一定被迫分解脂肪,生產酮體來當能源(生酮=生產酮體),但是如果你攝取了大量膳食脂肪,身體就會優先燃燒這些膳食脂肪,燒完了才輪到燃燒體脂,所以想要減重的人除了減少醣類之外,還要控制膳食脂肪的攝取量。
    膳食脂肪的用意是幫助身體暫時止飢,順利度過低醣飲食的適應期。膳食脂肪只是配角,低醣才是主角!
    不要妄想用脂肪去作弊,以為攝取了高醣,再用更高的脂肪去維持生酮的比例就能維持生酮狀態。很對不起!醣類一提高,生酮狀態就結束了,多餘的脂肪都會送進體脂倉庫妥善保管。
    最後,我們還要考慮一個配角,那就是蛋白質。因為蛋白質可以進行糖質新生轉換成葡萄糖(80%的糖質新生是由蛋白質轉化的),所以太多蛋白質會使葡萄糖的量降不下來。

  • 其實,我的生酮飲食觀念是偏向於斷食,而不是刻意增加膳食脂肪來達成高脂的比例。因為油脂的缺口可以由體脂自動填補,另外也可以由過剩的醣類與蛋白質去轉換成脂肪來填補。只要空腹時間夠長,生酮狀態是水到渠成,自然達成。我認為斷食才是真正適合自己的生酮飲食,斷食時的三大營養素比例是因人而異的,身體視需要而自動調節成最佳比例,不是人為猜測的比例。所以,補充外酮,我都稱之為假生酮。

  • 不管你是採取啥飲食,只要空腹時間夠長,肝醣與蛋白質的庫存減少到一定程度,身體就會切換到燃燒體脂為主的模式,自動進入所謂的生酮狀態。肝醣有庫存,大家都知道,蛋白質有庫存,很多人不知道,當我們吃了一頓蛋白餐,蛋白質會暫存在小腸(血液中也暫存了一些),然後慢慢釋放達8小時之久,而蛋白質的釋放意味著糖質新生還很旺盛,葡萄糖的供應量還很多,身體不會切換成燃脂為主的生酮模式,一定要等到肝醣與蛋白質的庫存都差不多快用完了,生酮的量才會大增,有別於平常的少量生酮。生酮是一直在進行的,身體是混合引擎,葡萄糖與酮體是同時存在的,差別是量的多寡而已,所謂生酮狀態都是指酮體占大宗的能源狀態,不是完全沒有葡萄糖,同理,非生酮狀態也不是完全都是燃燒葡萄糖,酮體還是存在,量很少而已。

  • 生酮關鍵是胰島素濃度,路線有二:
    1.低醣+低蛋白,油脂不是重點。這條路線的胰島素上升不高,很快就能降下來,進入燃燒模式,燃燒的原料剛開始是肝醣居多,由於肝醣不多,很快就輪到燃燒脂肪,進入生酮狀態。脂肪的來源有二種,膳食脂肪與體脂,身體會優先燃燒膳食脂肪,最後才燃燒體脂。希望燃燒體脂的人就不能無限制攝取膳食油脂。
    2.不限制醣與蛋白質,走這條路線就要延長空腹時間來降低胰島素。一開始,醣類與蛋白質太多,胰島素上升太多,身體進入儲存模式,醣類先儲存為肝醣,過剩的醣轉與蛋白質再轉換成體脂儲存,接著一定要延長空腹,直到胰島素下降了,身體再去燃燒這些儲存的燃料。關鍵是空腹時間一定要夠長,甚至需要斷食才能燃燒到體脂,因為這條路線有幾個障礙:1.胰島素太高,2.肝醣儲存太多,所以需要較長的時間讓胰島素降下來,同時也需要較長的時間去燒掉肝醣,等到肝醣減少到相當的量,身體才會大宗燃燒脂肪,進入生酮狀態。所以這條路線比較慢。至於那些三餐+點心的高糖高蛋白飲食者,是很難生酮的。

  • 防彈、MCT、C8作為中繼站或治療某些腦部疾病是OK的,最後還是要乖乖走上斷食之路,因為過多的外酮除了卡位之外,還會刺激胰島素,進行儲存工作。你不燒體脂,你偏要燒MCT、C8,你的體脂當然不會減少,或是減少的不夠多。體脂包括內臟脂肪,如果內臟脂肪依舊很多,內臟機能就會依舊衰弱。還有,脂肪也是荷爾蒙器官,你不減體脂,你如何改善脂肪相關的荷爾蒙狀態?

  • 斷食時身體也製造了酮體(內酮),但是胰島素濃度是維持超低水平。相反地,攝取大量中短鏈脂肪酸來製造大量外酮,往往忽略了酮體也會升高胰島素的事實,而且升高的強度跟蛋白質差不多,這就是大問題了!事實上,脂肪分解只有一部份是產生酮體,這個酮體是肝臟在缺葡萄糖之下製造出來餵養大腦的,產量不需要很多,不是生酮越多就越好,現在大家都被酮體的數值綁死了,有酮體就拍手叫好,我想這個酮體的觀念還需要進一步深思。像北極熊冬眠,不吃不喝不尿不動,可長達7個月之久,大家一定認為牠是高度生酮狀態,事實上牠不是高度生酮狀態,牠的BHB是低於0.5mmol,因為牠是利用脂肪分解後的甘油來支援肝臟的糖質新生。那麼,人類呢?我的看法是,酮體或許也跟葡萄糖一樣,都是不能久留的東西,太多,身體一定要盡速排掉或轉換回三酸儲存起來。

  • 根據Marty Kendall的統計,血液中葡萄糖與酮體總和超過6.2mmol,就會額外分泌胰島素來儲存這些過剩的能源,而超過的部分,可能來自葡萄糖,也可能來自酮體(外酮),所以長期大量補充外酮,還是可能造成胰島素長期過高,進一步演變成胰島素抗阻或三高或肥胖。這跟大量喝糖水、吃澱粉一樣,能源超載的後果都會走上代謝症候群的地步!這是大家必須留意的問題!

     

 

淨值真的就是淨值嗎?

  • 摘自《生酮飲食聖經》p.67~68

  • 拿起一個蛋白質棒或「無糖」的零食,標籤上可能會說「低淨碳水化合物」,甚至是「零淨碳水化合物」。不幸的是,由於營養標籤的規定,這個數字未必代表這種蛋白質棒是生酮飲食的好選擇。首先,在這些產品中使用的一些「纖維」實際上會增加血糖與胰島素,因此它們不算是纖維。FDA目前正深入研究這些偽纖維,以要求食品公司調整其產品的標示。
    其次,食品公司有時使用糖醇來增加食品的甜味。有鑑於目前的營養標籤規定,這些醣醇可以從總碳水化合物的計數中扣掉;也就是即使一個產品有20克的碳水化合物和15克的糖醇,其標籤上可以標記「5克淨碳水化合物」。類似於標記不實的「纖維」,其中一些糖醇(例如無糖小熊軟糖中的麥芽糖醇)可能會影響血糖,更糟糕的是,如果大量食用,你的胃肯定會受不了。食用這類型的食物要謹慎,特別是開始實施生酮飲之際。小心行銷的噱頭如淨碳水化合物,以及要研究產品中使用的纖維或糖醇,以確保它不會提高你的血糖值或讓你狂跑廁所。如果你想深入研究,你可以嘗試各種食物或零食,並使用你的血糖儀來測量它們如何影響你的血糖。欲瞭解更多訊息,你可以參考網站www.ketogenic.com/nutrition/guidetofiber以瞭解何謂「真正」的纖維。

 

 

完全依賴葡萄糖的細胞

  1. 大腦的一部份細胞

  2. 紅血球、白血球

  3. 視網膜、水晶體、角膜

  4. 睪丸生殖腺上皮細胞

  5. 腎髓質上皮細胞


特殊狀況下依賴葡萄糖的細胞:

  • 低氧狀態下的骨骼肌

  • 胚胎組織

 

 

Darren Schmidt的觀點

  • 人不能一直處於生酮狀態,即使是愛斯基摩人,也不是一年365天都是生酮狀態。春夏時他們還是會脱酮。

  • 飲食需要變化。例如:
    週一到週五:生酮飲食。(低醣、中蛋白質、高脂)
    週六:24小時間歇性斷食,只能吃一餐(晚餐),一樣是生酮餐。
    週日:吃三餐(正常餐,提高碳水或蛋白質來結束生酮)。
    公式:生酮餐+間歇性斷食+正常餐,三者循環不已。

  • 編者補充:Schmidt的觀點大家參考就好!因為長期生酮出問題者,不能全怪生酮造成的,這些人的問題還需要追查進一步的原因,例如:
    1.發炎食物可能沒有排除,例如:奶製品、豆類、代糖、植物油、茄類食物.......等。
    2.生化反應所需的輔助營養素可能沒有補齊,因為生酮飲食很容易偏食,很可能錯過植物性食物特有的營養素。
    3.其他因素:壓力、抽菸、缺乏運動、環境毒素、重金屬......等。


 

生酮飲食與癌症

  • 利用生酮飲食來治癌症,儘管理論上很合邏輯,臨床結果卻是讓人失望的!大家可以參考《Dr. Gonzalez dismantles the ketogenic diet for cancer》這篇專文。我個人的讀後心得如下:

    Dr. Gonzalez排除了生酮飲食的治癌效果。因為他的好友--減肥權威阿金博士--已經實驗過了,無效!雖然生酮飲食治癌的理論非常合理、非常吸引人,但是應用在臨床上卻是失敗的!而且很多抗癌成功者都是採用高醣飲食。這些存活的實例否決了癌細胞只能靠葡萄糖維生的理論。(Dr. Kelley認為癌症是缺乏胰臟蛋白質分解酵素所造成的,所以他會限制癌症患者的蛋白質攝取量,尤其是煮熟的動物性蛋白質,以免耗盡胰臟的蛋白質分解酵素。這些蛋白質分解酵素可以分解癌細胞的偽裝外衣,讓免疫細胞能夠辨識癌細胞,進而消滅癌細胞。)

    Dr. Gonzalez推論癌細胞可能比我們想像的還要強韌,他們可能具有適應無糖環境的能力,例如:分解肌肉中的蛋白質來當食物,例如:麩醯胺酸(Glutamine)

    Dr. Gonzalez的派別是採用三足鼎立的方法治癌--客製化飲食+大量胰臟酵+咖啡灌腸,他認為要徹底殺死癌細胞必須殺死癌細胞的元祖--癌幹細胞。如果只是殺死它的子孫而不根除元祖,就會出現腫瘤縮小了但是癌細胞依然存在,而且源源不斷,最後還是轉移出去,造成死亡。

    唉!前幾天我還很高興地貼出【生酮飲食+限制卡路里+高壓氧】的癌症新療法,想不到生酮飲食與高壓氧都被Dr. Gonzalez否決了!

    臨床經驗是很現實的,失敗就是失敗,原因不明,有待日後科學家去解開謎底!

    雖然阿金博士的生酮飲食治癌失敗,但是Cantin女士採用她自創的生酮飲食卻是成功地治好她自己的乳癌,這又怎麼解釋?或許誠如Cantin女士所說的:阿金版生酮飲食沒有排除食物中的過敏原與毒素,例如:穀類、乳製品、紅肉、基因改良食物、重金屬、含氯與氟的自來水、加工食品、MSG(味精)...等。

    為何排除食物中的過敏原與毒素會成為治癌成功的關鍵因素呢?須知一個健康的人是不會罹癌的,只有當免疫力破產了才可能罹癌!而排除過敏原與毒素,恰好可以減輕免疫負擔,讓身體保留較多的免疫力去打擊癌細胞!這是非常重要的一環!很多治癌專家使盡各種辦法去消滅癌細胞,例如:手術、化療、電療、熱療、食療、酵素療法、週波療法、木馬伏兵療法….等五花八門,這些療法確實能減少癌細胞,甚至完全消滅癌細胞,但是只要過敏原與毒素沒有清除,身體的免疫力就不可能充足癌細胞就有機會反撲,就好像警力不足,壞人會趁機作亂一樣。這也是癌症容易復發的原因之一!

  • 主張癌症是代謝疾病的學者Tom Seyfried發現,採用生酮飲食來限制癌細胞最喜歡的食物(葡萄糖)的策略仍然有瑕疵,因為無論我們攝取再少的醣類,或再少的的食物,人體仍然會設法阻止我們血糖掉到足以殺死癌細胞的低水平。也因此,Seyfried堅決主張我們需要借助降糖藥或其他能夠加強斷食與生酮飲食的藥物來把血糖降到足以殺死癌細胞的低水平。很可惜,這種有效又安全的藥物並不存在!

  • 參考資料

    http://www.chrisbeatcancer.com/dr-gonzalez-dismantles-ketogenic-diet-for-cancer/

    《Cancer and the New Biology of Water》--Thomas Cowan

  • 三足鼎立的治癌法,請參考→治癌的意外發現

 

 

 

Brad Pilon的觀點

  • 減重有二部分,一個是水重,另一個是非水分的體重。怎麼知道非水分的體重流失多少?我們可以用碳原子的流失量來換算。(水是氫+氧的組合,醣類與脂肪酸都是碳+氫+氧的組合,蛋白質是碳+氫+氧+氮的組合。)

  • 碳是如何排出體外?食物經過消化代謝,最終產物之一是二氧化碳,我們就是靠呼吸排出二氧化碳。排出越多,代表非水分的體重減少越多,這就是減重最樂意看到的結果。

  • 平均而言,碳水化合物的碳重量大約是40%,脂肪酸的碳重量大約是78%。

  • 生酮狀態下,我們並沒有呼出較多的二氧化碳,尿液排出的酮體也微乎極微。那麼,生酮飲食是怎麼減重的?比較其他飲食法,生酮飲食的碳原子出貨量相差不大,那麼我們就來清查它的進貨量。例如:同樣是吃進2000大卡,如果是吃碳水化合物,我們會吃進200克的碳原子(2000÷4×40%=200),但是如果是吃脂肪酸,我們只會吃進175克的碳(2000÷9×78%=173)。這就是高脂的生酮飲食殊勝之處:吃進的碳原子比較少。

原信件內容:

Ketogenic Diets or ‘Keto-diets’ are becoming popular... again.

This is not a new idea or trend. It was very popular in 2009, and back in 1996 (I’m starting to think diets have a twelve to fifteen year cycle)

Ketogenic diets are based on the idea of Ketosis - Ketosis is a state you body enters when you quickly move into burning predominately fat as a fuel.

When fatty acid oxidation is ramped up quickly, your liver can’t keep up and some of the fatty acids are ‘incompletely burned’ leaving ketones as a biproduct.

【Carbon Explanation: Remember that Fatty Acids are long chains of Carbon, and when we are using fat as a fuel we are simply cutting a carbon off the chain and then move that carbon out of our bodies through our breath as carbon dioxide. When our needs outweigh the speed we can ‘cut’ these carbons, we get lazy and start cutting at every third or fourth carbon, creating carbon ‘fragments’ called ketones.】

Luckily we can easily use these ketones as a fuel. In fact, ketones become the preferred fuel in many tissues, especially your brain.

【Carbon Explanation: We are still able to break ketones down to create carbon dioxide which we then exhale.】

You start to enter Ketosis somewhere between 16 and 20 hours of fasting, and it continues to increase the longer you fast. Then after about three weeks, your body is fully adapted to fat and you go back to burning predominantly fat as a fuel.

In summary - Ketones are produced when fatty acids are being used as a fuel at a rate that is quicker then we can handle, leading to the incomplete breakdown of fatty acids and the creation of ketones. Ketosis is temporary as we eventually are able to increase our ability to fully use Fatty Acids as a fuel source, Ketosis typically lasts two to three weeks, depending on the person.

Ketosis is a Hallmark of prolonged fasting. However, since most people don’t want to fast, there are also Ketogenic diets based on consuming mostly Fat.

And here is the focus of this email - Ketogenic Diets and their use for weight loss.

Ketogenic diets are Low carb diets (usually under 50 grams per day), that are also low (ish) protein diets - typically recommending under 100 grams of protein, the rest of the diet is Fat.

Upwards of 70% of your daily calories come from Fat when you are on a Ketogenic Diet.

People either Love or Hate ketogenic diets.

Our main concern is - Do they somehow create BETTER or MORE fat loss?

For weight loss we know our main concern is non-water weight leaving the body. In other words, carbon loss.

Since being in ketosis is the result of a high level of fat burning, we know when you are in ketosis the carbon lost through our breath are from fat. So if we are interested in Fat Loss (which most of us are) being in ketosis is a good indication you have temporarily hit a maximal rate of fat burning.

I have not seen any evidence that being in ketosis increases the amount of CO2 you expire. To the best of my knowledge you don’t breathe heavier or harder when you are in ketosis…

Based on the lack of change in expired CO2 your weight loss will remain more or less the same, with the following possible exception.

When you are in Ketosis you also breathe out ketones. You also lose ketones through your urine. The amount is small, but these are still additional carbons escaping your body that you would otherwise not be losing.

【Carbon Explanation: During Ketosis there is a small extra amount of Carbon that leaves your body, however the relevance is most likely very small.】

The only other possible explanation for increased non-water weight loss would be an increase in carbon loss through some of the fat you are eating not getting absorbed. However this has not been reported in any literature.

Bottom line is that being in Ketosis ensures that almost all the carbon leaving your body comes from fat. However there is the main difference between fasting and a high-fat ketogenic diet…

With fasting we know the carbons are coming from your body fat, since there are no other fat sources. With a ketogenic diet the Carbon will be from a mix of body fat and the fat you are eating.

You are burning a maximal amount of fat, but it is a mix of fat from your body fat, and fat from your diet.

In other words you may be burning just as much fat as when you are fasting, but the amount of fat you are burning that was once body fat may be smaller.

The only other weight loss benefit of a ketogenic diet is the amount of food you get to eat while still losing weight…

Remember that Carbohydrates are roughly 40% carbon, while fat is roughly 78%.

This means 2,000 Calories worth of carbohydrates contains roughly 200 grams of Carbon, while 2,000 calories worth of fat contains roughly 175 grams of carbon.

So someone on a ketogenic diet may be surprised that they can eat a little more than they thought they could while still losing weight... this isn't magic - It's carbon 

Bottom line: We are all losing weight every minute of every day. As long as the carbon coming in is less than the carbon going out, ANY DIET will allow for weight loss. Some diets allow for more of that weight to come from body fat than others. If the carbon balance is correct, a ketogenic diet will allow for weight loss, and for much of that weight to come from fat.

Your friend and Advocate,

      

Brad

 

 

Dispelling Keto Myths

摘自《Keto.》p.191

In this section, we dispel some common myths about the keto lifestyle.

 

MYTH 1: KETO IS ALL ABOUT HORMONES; CALORIES DON'T MATTER ?

This one we must unpack a bit because it is somewhat complicated. First, calories do matter. However, we are not saying we are back to the old calories-in, calories-out way of thinking. Hormones matter, too. They both matter! And restoring proper hormone signaling is one of the great aspects of a well-formulated ketogenic diet. When you restore proper hormone signaling, you reduce hunger and cravings, which makes eating less much easier (enabling more fat loss).

As described in Chapters 2 and 3, insulin signaling breakdown occurs when too many of your fat cells get overstuffed and inflamed. To reverse this, you must reduce the size of these fat cells by enabling lipolysis (pulling fat from fat stores to be used as fuel). Fuel-even fat-coming in through the foods you eat raises insulin levels enough to shut off lipolysis and stop the shrinking of the fat cells that is so important for healing. In fact, when you consume excess fat, your fat cells are enlarged.

When you are keto-adapted, you can use your dietary fat and body fat equally. You want your body to use stored body fat for fuel so that you lose excess body fat.

That means while we are not saying this is the same old calories in, calories out way of thinking, we are also not saying that calories don't matter. Hormones are important, but so are calories. They both matter !

 

MYTH 2: SLEEP, HORMONE, OR THYROID ISSUES REQUIRE ADDITIONAL CARBS ?

Carb-ups involve adding carbs in the evening, supposedly to help with various issues. Some people believe that doing carb-ups helps with sleep, hormones, and thyroid function, among other things.

However, carb-ups just cover up the real issues, and it's plain wrong to think that carb-ups are necessary.

Hormone signaling isn't restored overnight. It takes time. The keto lifestyle will help get your body back into a natural hormone balance-you just need to give it time.  Adding carbs just sets you back, introduces cravings, or, even worse, starts a carb binge.

You are much better off to address the root cause and take some supplements to help balance out your hormones more quickly while sticking to a ketogenic diet. For more information about how to make modifications for different conditions, see Chapter 6.

Also, carb-ups or carb-cycling on the weekends leads to more lean mass loss, and you definitely don't want that. A deep keto state is where you start preserving your lean mass. With carb-ups, you end up in a kind of in-between state in which your body isn't fully keto-adapted but also isn't getting enough carbohydrates to be a full sugar burner. Consequently, you use more lean protein to satisfy the glucose needs, which leads to loss of lean mass.

People who advocate this carb-up approach say things like, "I eat 80 grams of carbs but stay in ketosis." This is related to myth 5, "High Blood Ketones Equal Nutritional Ketosis." These same people advocate lots of fat bombs, bulletproof coffee, and lots of other added fat. As we describe in myth 5, this isn't nutritional ketosis. You have elevated ketones because of the large amounts of external fat, not because you're making them from your fat stores (which is what you want for true nutritional ketosis and fat loss). Also, it doesn't mean much when you test for ketones in the morning after having had a carb-up the night before. After twelve hours of not eating (overnight), most people show some elevated ketones, whether they are ketosis or not.

As Dr. Steven Phinney, one of the most respected researchers on ketogenic lifestyles, says, "Forcing the pancreas to make more insulin by eating more carbs clearly doesn't do a lot of good for type 2 diabetics, and we think the same logic applies here for thyroid function."

Keto is very low-carb for a reason. Adding carbs would just mess up all the healing that keto can provide. Stop chasing ketones and chase results !

 

MYTH 3: NOT ALL FAT IS ABSORBED WHEN YOU'RE KETO ?

This one is pretty abstract and isn't supported by any biology or evolutionary facts. The idea is that not all the fat you eat get absorbed; when you're in ketosis, lots of it just goes through you and into the stool. There are three important points about this myth:

  • Studies have shown that only about 5 grams of fat a day is passed through the stool. 2 The rest is either stored or used as fuel.

  • Do you remember Olestra? It was a fake, processed oil produced in the 1990s and used in potato chips. The big "benefit" was that the oil didn't get digested, which meant that you really did just poop it out. The makers of Olestrars had to include a warning label stating that it could cause abdominal cramping, loose stools, and even uncontrolled anal leakage! And those side effects would come from maybe 5 to 10 grams of extra fat going out the digestive tract. We can't imagine what would happen if you truly had 100 grams of fat just "going out" because being keto means you don't absorb the fat. We don't think we would want that uncontrollable result.

  • This last point comes from an evolutionary perspective. If we didn't absorb the fats we ate, we wouldn't be around as a species. Hunter-gathers ate lots of animal fats in the summer months to add extra body fat to make it through the lean winters. If we didn't use all this wonderful energy coming into our bodies, that wouldn't be a very smart biological system.
    Life doesn't just waste energy. If anything, it holds onto every bit it can so you can make it through the lean times.

MYTH 4: EATING FAT DURING A FAST WON'T BREAK YOUR FAST ?

Fat is calories. The whole point of fasting and intermittent fasting is not to have any calories to enable your body to do repair activities (autophagy and apoptosis; see Chapter 9 for details) and utilize more stored body fat for fuel. If you add calories you raise insulin, which means the process stops and so do the benefits. Any calories, including those from fat,raise insulin enough to stop lipolysis and decrease the benefits of fasting.

We believe the thinking behind this myth comes from the thought, "If l am showing high ketones, then my fast is okay."

Again, having higher ketones does not mean better results. And for best results, fasting means no calories (water only).

 

MYTH 5: HIGH BLOOD KETONES EQUAL NUTRITIONAL KETOSIS ?

Nutritional ketosis means your body is making ketones to fuel your body and you are primarily running on stored body fat (free fatty acids and ketones). This only happens when carbs get low enough, and you spend less time stimulating insulin.

There are several things that can elevate blood ketones without it coming from your body (what you really want). These include coconut oil, MCT oil, MCT powders, and exogenous ketones.

These all can raise blood ketones. You can eat a big bowl of rice loaded with MCT oil and still show "keto" blood ketone levels of, say, 0.5 mmol. However, you are not in nutritional ketosis. This myth is what leads some to say, "I eat 80 grams of carbs a day and am in ketosis." They are just adding lots and lots of fats to keep blood ketones elevated a bit. They are not in nutritional ketosis, and they aren't using body fat for fuel. Don't chase ketones; chase results !

 

MYTH 6: HIGHER KETONES ARE BETTER ?

Tere is no correlation between blood ketone levels and weight loss and healing. High ketones don't mean greater weight loss. There are some cases where higher blood ketones are beneficial, such as with Alzheimer's disease or for dealing with seizures. But if weight loss and healing are your goal, then more is not necessarily better.

Blood ketones are simply the diference in fuel generated and fuel used. If you are active and have been in ketosis for a while, you can have low ketones even if you're eating few to zero carbs. That is because your body is using the ketones for fuel, which is leaving fewer ketones in the bloodstream. We know bodybuilders who are very keto and never have blood ketones much above 0.3 mmol or so. Focus on getting carbs low enough, and you will be in ketosis regardless of what your fat intake is, and regardless of what your blood ketones say. Remember: Don't chase ketones; chase results !

 

MYTH 7: EXOGENOUS KETONES WILL HELP WITH WEIGHT LOSS ?

As shown in Chapter 3, any fuel coming into the body stops lipolysis, which makes perfect sense. If your body wants to tightly control the amount of fuel in the blood at any given time, it must stop adding fuel to the blood as soon as any comes in through the diet. This is the same argument as the next myth about adding fat when weight loss stalls. You want your body to be making ketones from your body fat rather than making ketones from dietary fat for fffuel. You know what we're going to say, right? Don't chase ketones; chase results !

 

MYTH 8: IF YOU ARE STALLED, ADD MORE FAT ?

This advice is also common and is very flawed. There are some keto "experts" who give this damaging advice all too often. Not losing weight? Eat more fat. Losing hair? Eat more fat. Some people recommend lowering protein to dangerously low levels while raising fat. They tell people to get less than 50 grams of protein while eating 200 grams or more of fat! Chapter 8 makes clear why this is such bad advice. You are exchanging the most nutrient-dense food (animal protein) for one of the least nutrient-densed food (fat). You are also using more and more dietary fat for fuel and using less and less body fat for fuel. This is the opposite of what you want for fat loss.

 

MYTH 9: TOO MUCH PROTEIN TURNS INTO SUGAR ?

This is a widely held belief in the keto community, but it's another myth that doesn't have scientific or biological backing. Yes, there is a metabolic pathway for converting protein to glucose. It is called gluconeogenesis. However, that pathway is always on, meaning that when the body needs more glucose, it produces more glucose.

Studies have shown that increases in protein intake have little or no effect on the rate of gluconeogenesis. In fact, most of the gluconeogenesis that occurs when you are keto-adapted is from glycerol. Remember our discussion of lipolysis in Chapter 3? The first step in lipolysis is where a triglyceride molecule has the glycerol stripped off, which frees three FFA molecules to enter the bloodstream to be used as fuel. The glycerol molecule is then sent to the liver; two glycerol molecules combine to form one glucose molecule.

Gluconeogenes is is not an enemy of a ketogenic diet; instead, gluconeogenes is what makes a keto diet possible. With a carbohydrate intake of 20 grams or less per day, your body wouldn't have enough glucose to fuel the parts of your brain that can run only on glucose.

Gluconeogenesis makes the extra glucose needed to fuel the brain and thus makes a ketogenic diet possible.

Some people point out that type 1 diabetics must dose insulin at about one-half the rate of carbohydrates to prevent large blood glucose spikes. However, this isn't the result of gluconeogenesis.

When you eat protein, both insulin and glucagon are released.

Insulin is released to stimulate protein synthesis or the uptake of amino acids in muscle cells. This process makes them less available for gluconeogenesis. The glucagon is released to stimulate the uptake of amino acids into the liver for gluconeogenesis. The release of two competing hormones serves a very important purpose. A rise in insulin lowers blood sugar levels. A rise in glucagon raises blood sugar levels. In a non-diabetic, this ensures that the amino acids get used for protein synthesis but also ensures that blood sugar doesn't drop to dangerously low levels.

That means the insulin and glucagon cancel each other out with respect to glucose levels while the insulin still acts on the protein to perform muscle synthesis. This is a pretty neat trick.

In a type 1 diabetic, the release of glucagon without insulin-type 1 diabetics don't produce insulin as they should-can cause a blood sugar rise after meals that are high in protein. Also, the absence of insulin increases the amount of protein used for gluconeogenesis because there isn't enough insulin to counter the rise of glucagon, which is why a diabetic needs to account for protien in insulin dosing.

Gluconeogenesis is what makes a ketogenic diet possible. It is always running and regulating our blood sugar levels, and it's demand driven. If blood glucose goes low, the body makes more. It does have some supply variations (very high protein levels can produce excess protein that gets turned into more blood glucose), but the effect is minimal. Many people can eat 150 grams of protein in one sitting with a negligible effect on blood sugar. So protein is not the enemy of a ketogenic diet. And, as explained in Chapter 8, it can be the key to improving nutrient density in your diet.

 

MYTH 10: KETO REQUIRES 80 PERCENT FAT, 15 PERCENT PROTEIN, AND 5 PERCENT CARBS ?

The problem with this belief is that it is very dependent on calories. One person could be eating 3000 calories, in which case the necessary protein would be 112 grams a day. A person eatin 1,000 calories would need only 37 grams of protein a day to reach that 15 Percent goal. We know that protein is dependent on lean mass: The more lean mass you have, the more protein you need top maintain it. That means you should always track macros (fat, protein, and carbs) in grams, not percentages.

A well-formulated ketogenic diet is a whole-food, organic approach to keto with low carbs and adequate protein. Some People in the keto community are giving advice that is holding people back and even causing more damage. We hope we have leared up some of the confusion about various myths.

If handled correctly, a well-formulated ketogenic diet can produce amazing results for weight loss and a wide range of chronic diseases. We have seen it firsthand in thousands of clients and with everything from Alzheimer's disease, multiple sclerosis, metabolic disease, cancer, autoimmune issues, thyroid problems, and so much more. We believe that it's important to have clarity regarding what a well-formulated ketogenic diet really is because the stakes-your health-are really high.

If you are doing the things we outline for a well-formulated ketogenic diet and are still having trouble reaching your goals, the next section about troubleshooting might help you get the weight loss and healing going again.

 

 

The Ketogenic Diet – An Overview

Posted by: Gabriela Segura, MD

Ketosis is an often misunderstood subject. Its presence is thought to be equal to starvation or a warning sign of something going wrong in your metabolism. But nothing could be farther from the truth, except if you are an ill-treated type 1 diabetic person.[1] Ketones – contrary to popular belief and myth – are a much needed and essential healing energy source in our cells that comes from the normal metabolism of fat.

The entire body uses ketones in a more safe and effective way than the energy source coming from carbohydrates – sugar AKA glucose. Our bodies will produce ketones if we eat a diet devoid of carbs or a low carb diet (less than 60 grams of carbs per day).[2] By eating a very low carb diet or no carbs at all (like a caveman) we become keto-adapted.

In fact, what is known today as the ketogenic diet was the number one treatment for epilepsy until Big Pharma arrived with its dangerous cocktails of anti-epileptic drugs. It took several decades before we heard again about this diet, thanks in part to a parent who demanded it for his 20-month-old boy with severe seizures. The boy’s father had to find out about the ketogenic diet in a library as it was never mentioned as an option by his neurologist. After only 4 days on the diet, his seizures stopped and never returned.[3] The Charlie Foundation was born after the kid’s name and his successful recovery, but nowadays the ketogenic diet is available to the entire world and it’s spreading by word of mouth thanks to its healing effects.

It is not only used as a healthy lifestyle, it is also used for conditions such as infantile spasms, epilepsy, autism, brain tumors, Alzheimer’s disease, Lou Gehrig’s disease, depression, stroke, head trauma, Parkinson’s disease, migraine, sleep disorders, schizophrenia, anxiety, ADHD, irritability, polycystic ovarian disease, irritable bowel syndrome, gastroesophageal reflux, obesity, cardiovascular disease, acne, type 2 diabetes, tremors, respiratory failure and virtually every neurological problem but also cancer, and conditions were tissues need to recover after a loss of oxygen.[4]

Our body organs and tissues work much better when they use ketones as a source of fuel, including the brain, heart and the core of our kidneys. If you ever had a chance to see a heart working in real time, you might have noticed the thick fatty tissue that surrounds it. In fact, heart surgeons get to see this every day. A happy beating heart is one that is surrounded by layers of healthy fat. Both the heart and the brain run at least 25% more efficiently on ketones than on blood sugar.

Ketones are the ideal fuel for our bodies unlike glucose – which is damaging, less stable, more excitatory and in fact shortens your life span. Ketones are non-glycating, which is to say, they don’t have a caramelizing aging effect on your body. A healthy ketosis also helps starve cancer cells as they are unable to use ketones for fuel, relying on glucose alone for their growth. [5]The energy producing factories of our cells – the mitochondria – work much better on a ketogenic diet as they are able to increase energy levels on a stable, long-burning, efficient, and steady way. Not only that, a ketogenic diet induces epigenetic changes[6] which increases the energetic output of our mitochondria, reduces the production of damaging free radicals, and favors the production of GABA – a major inhibitory brain chemical. GABA has an essential relaxing influence and its favored production by ketosis also reduces the toxic effects of excitatory pathways in our brains. Furthermore, recent data suggests that ketosis alleviates pain other than having an overall anti-inflammatory effect. [7]

The ketogenic diet acts on multiple levels at once, something that no drug has been able to mimic. This is because mitochondria is specifically designed to use fat for energy. When our mitochondria uses fat as an energetic source, its toxic load is decreased, expression of energy producing genes are increased, its energetic output is increased, and the load of inflammatory energetic-end-products is decreased.

The key of these miraculous healing effects relies in the fact that fat metabolism and its generation of ketone bodies (beta-hydroxybutyrate and acetoacetate) by the liver can only occur within the mitochondrion, leaving chemicals within the cell but outside the mitochondria readily available to stimulate powerful anti-inflammatory antioxidants.  The status of our mitochondria is the ultimate key for optimal health and while it is true that some of us might need extra support in the form of nutritional supplementation to heal these much needed energy factories, the diet still remains the ultimate key for a proper balance.

Our modern world’s staple energetic source is sugar which needs to be processed first in the cell soup before it can be passed into the energy factory of the cell- the mitochondrion. Energy sources from fat don’t require this processing; it goes directly into the mitochondria for energetic uses.  That is, it is more complicated to create energy out of sugar than out of fat. As Christian B. Allan, PhD and Wolfgang Lutz, MD said in their book Life Without Bread:

Carbohydrates are not required to obtain energy. Fat supplies more energy than a comparable amount of carbohydrate, and low-carbohydrate diets tend to make your system of producing energy more efficient. Furthermore, many organs prefer fat for energy.

The fact is you get MORE energy per molecule of fat than sugar. How many chronic and autoimmune diseases have an energy deficit component?  How about chronic fatigue?  Fibromyalgia?  Rheumatoid Arthritis?  Multiple Sclerosis? Cancer? Back to Allan and Lutz:

Mitochondria are the power plants of the cell. Because they produce most of the energy in the body, the amount of energy available is based on how well the mitochondria are working. Whenever you think of energy, think of all those mitochondria churning out ATP to make the entire body function correctly. The amount of mitochondria in each cell varies, but up to 50 percent of the total cell volume can be mitochondria. When you get tired, don’t just assume you need more carbohydrates; instead, think in terms of how you can maximize your mitochondrial energy production…

If you could shrink to a small enough size to get inside the mitochondria, what would you discover? The first thing you’d learn is that the mitochondria are primarily designed to use fat for energy!

In short, let fat be thy medicine and medicine be thy fat!

You will think that with all of this information we would see ketogenic diets recommended right and left by our health care providers, but alas, that is not the case. Mainstream nutritionists recommend carbohydrates AKA sugar as the main staple of our diets. The problem with this (and there are several of them) is that in the presence of a high carb diet we are unable to produce ketones from the metabolism of fats, thus, depriving ours bodies from much healing ketone production.  The fact that we live in a world which uses glucose as a primary fuel means that we eat a very non healing food in more ways than one.

I have been doing the low carb diet for about a week and a half now and I must say, I am really starting to feel amazing!!!  The first few days my head hurt, I felt lethargic, and my legs felt so heavy. But after I got past that, I have so much energy. I don’t get tired anymore around 3pm. The best part is, I am not constantly thinking and obsessing about food. I feel a real sense of inner calm. My skin looks better, my hair looks better too.
I have been having bacon and eggs for breakfast, a pork chop or other piece of meat for lunch, and usually some pork and sometimes some green beans for dinner. I have also lost some weight!  Woo hoo!!! -Angela, United States. Sott.net forum.

We have been on a ketogenic diet for nearly three million years and it has made us human. It was the lifestyle in which our brains got nurtured and evolved. But not anymore, unless we all make an effort to reclaim this lost wisdom. Nowadays the human brain is not only shrinking, but brain atrophy is the norm as we age and get plagued with diseases such as Alzheimer’s disease, Parkinson’s disease, senile dementia and so forth.

In the mean time new research is starting to elucidate the key role of our mitochondria in the regulation of the cell cycle – the vital process by which a single celled fertilized egg develops into a mature organism, as well as the process by which hair, skin, blood cells, and some internal organs are renewed. In the complicated and highly choreographed events surrounding cell-cycle progression, mitochondria are not simple bystanders merely producing energy but instead are full-fledged participants.[8] Given the significant amount of energy needed to make all the nutrients required for cell division, it makes sense that some coordination existed. This long ignored and overlooked connection between the mitochondria and the cell cycle is something that is worthy of considerable more attention as we understand the role of diet in our bodies. We’ll have to take a closer look to this subject of ketosis, as it really holds the key to unlock our transformational pathways that will lead us to an outstanding healthy living.

Mitochondrial Dysfunction

Mitochondria are best known as the powerhouses of our cells since they produce the cell’s energy. But they also lead the genetic orchestra which regulates how every cell ages, divides, and dies. They help dictate which genes are switched on or off in every single cell of our organism. They also provide the fuel needed to make new brain connections, repair and regenerate our bodies.

Whether we are housewives, sportsmen or labor people, energy is a topic that concerns us all, every day and in every way. Our well being, behavior and ability to perform the tasks in front of us to do is our individual measure of energy. But how we derive energy from the foods that we eat?

There are many man-made myths surrounding energy production in the body and which foods supply energy. Mainstream science says that carbohydrates are what mitochondria use as fuel for energy production. This process is called oxidative metabolism because oxygen is consumed in the process. The energy produced by mitochondria is stored in a chemical “battery”, a unique molecule called adenosine triphosphate (ATP). Energy-packed ATP can then be transported throughout the cell, releasing energy on demand of specific enzymes. In addition to the fuel they produce, mitochondria also create a by-product related to oxygen called reactive oxygen species (ROS), commonly known as free radicals. But what we are not told is that mitochondria were specifically designed to use fat for energy, not carbohydrate.

Source: Christian B. Allan, PhD and Wolfgang Lutz, MD, Life Without Bread.

There are several very complicated steps in making ATP within mitochondria, but a look at 5 major parts of ATP production will be all that you need to know in order to understand how energy is created within our mitochondria and why fats are the key to optimize their function. Don’t get focused on specific names, just try to see the whole picture.

Step 1 – Transportation of Food-Based Fuel Source into the Mitochondria

Fuel must first get into the mitochondria where all the action happens. Fuel can come from carbs or it can come from fats. Fatty acids are the chemical name for fat, and medium and large sized fatty acids get into the mitochondria completely intact with the help of L-carnitine. Think of L-carnitine as a subway train that transports fatty acids into the mitochondria. L-carnitine (from the Greek word carnis means meat or flesh) is chiefly found in animal products.

Fuel coming from carbs needs to get broken down first outside the mitochondria and the product of this breakdown (pyruvate) is the one who gets transported inside the mitochondria, or it can be used to produce energy in a very inefficient way outside the mitochondria through anaerobic metabolism which produces ATP when oxygen is not present.

Step 2 – Fuel is Converted into Acetyl-CoA

When pyruvate – the product of breaking down carbs – enters the mitochondria, it first must be converted into acetyl-CoA by an enzymatic reaction.

Fatty acids that are already inside the mitochondria are broken down directly into acetyl-CoA in what is called beta-oxidation.

Acetyl-CoA is the starting point of the next step in the production of ATP inside the mitochondria.

Step 3 – Oxidation of Acetyl-CoA and the Krebs Cycle

The Krebs cycle (AKA tricarboxylic acid cycle or citric acid cycle) is the one that oxidizes the acetyl-CoA, removing thus electrons from acetyl-CoA and producing carbon dioxide as a by-product in the presence of oxygen inside the mitochondria.

Step 4 – Electrons Are Transported Through the Respiratory Chain

The electrons obtained from acetyl-CoA – which ultimately came from carbs or fats – are shuttled through many molecules as part of the electron transport chain inside the mitochondria. Some molecules are proteins, others are cofactors molecules. One of these cofactors is an important substance found mainly in animal foods and it is called coenzyme Q-10. Without it, mitochondrial energy production would be minimal. This is the same coenzyme Q10 that statins drug block producing crippling effects on people’s health. Step 4 is also where water is produced when oxygen accepts the electrons.

Step 5 – Oxidative phosphorylation

As electrons travel down the electron transport chain, they cause electrical fluctuations (or chemical gradients) between the inner and outer membrane in the mitochondria. These chemical gradients are the driving forces that produce ATP in what is called oxidative phosphorylation. Then the ATP is transported outside the mitochondria for the cell to use as energy for any of its thousands of biochemical reactions.

But why is fat better than carbs?

If there were no mitochondria, then fat metabolism for energy would be limited and not very efficient. But nature provided us during our evolution with mitochondria that specifically uses fat for energy. Fat is the fueled that animals use to travel great distances, hunt, work, and play since fat gives more packed-energy ATPs than carbs. Biochemically, it makes sense that if we are higher mammals who have mitochondria, then we need to eat fat.  Whereas carb metabolism yields 36 ATP molecules from a glucose molecule, a fat metabolism yields 48 ATP molecules from a fatty acid molecule inside the mitochondria. Fat supplies more energy for the same amount of food compared to carbs. But not only that, the burning of fat by the mitochondria – beta oxidation – produces ketone bodies that stabilizes overexcitation and oxidative stress in the brain related to all its diseases, it also causes epigenetic changes that produce healthy and energetic mitochondria and decreasing the overproduction of damaging and inflammatory free radicals among many other things!

Mitochondria regulate cellular suicide, AKA apoptosis, so that old and dysfunctional cells which need to die will do so, leaving space for new ones to come into the scene. But when mitochondria function becomes impaired and send signals that tell normal cells to die, things go wrong. For instance, the destruction of brain cells leads to every single neurodegenerative condition known including Alzheimer’s disease, Parkinson’s disease and so forth. Mitochondrial dysfunction has wide-ranging implications, as the health of the mitochondria intimately affects every single cell, tissue and organ within your body.

The catalysts for this destruction is usually uncontrolled free radical production which cause oxidative damage to tissues, fat, proteins, DNA; causing them to rust. This damage, called oxidative stress, is at the basis of oxidized cholesterol, stiff arteries (rusty pipes) and brain damage. Oxidative stress is a key player in dementia as well as autism.

We produce our own anti-oxidants to keep a check on free radical production, but these systems are easily overwhelmed by a toxic environment and a high carb diet, in other words, by today’s lifestyle and diet.

Mitochondria also have interesting characteristics which differentiate them from all other structural parts of our cells. For instance, they have their own DNA (referred as mtDNA) which is separate from the widely known DNA in the nucleus (referred as n-DNA),. Mitochondrial DNA comes for the most part from the mother line, which is why mitochondria is also considered as your feminine life force. This mtDNA is arranged in a ring configuration and it lacks a protective protein surrounding, leaving its genetic code vulnerable to free radical damage. If you don’t eat enough animal fats, you can’t build a functional mitochondrial membrane which will keep it healthy and prevent them from dying.

If you have any kind of inflammation from anywhere in your body, you damage your mitochondria. The loss of function or death of mitochondria is present in pretty much every disease. Dietary and environmental factors lead to oxidative stress and thus to mitochondrial injury as the final common pathway of diseases or illnesses.

Autism, ADHD, Parkinson’s, depression, anxiety, bipolar disease, brain aging are all linked with mitochondrial dysfunction from oxidative stress. Mitochondrial dysfunction contributes to congestive heart failure, type 2 diabetes, autoimmune disorders, aging, cancer, and other diseases.

Whereas the nDNA provides the information your cells need to code for proteins that control metabolism, repair, and structural integrity of your body, it is the mtDNA which directs the production and utilization of your life energy. A cell can still commit suicide (apoptosis) even when it has no nucleus nor nDNA.

Because of their energetic role, the cells of tissues and organs which require more energy to function are richer in mitochondrial numbers. Cells in our brains, muscles, heart, kidney and liver contain thousands of mitochondria, comprising up to 40% of the cell’s mass. According to Prof. Enzo Nisoli, a human adult possesses more than ten million billion mitochondria, making up a full 10% of the total body weight.[9] Each cell contains hundreds of mitochondria and thousands of mtDNA.

Since mtDNA is less protected than nDNA because it has no “protein” coating (histones), it is exquisitely vulnerable to injury by destabilizing molecules such as neurotoxic pesticides, herbicides, excitotoxins, heavy metals and volatile chemicals among others. This tips off the balance of free radical production to the extreme which then leads to oxidative stress damaging our mitochondria and its DNA. As a result we get overexcitation of cells and inflammation which is at the root of Parkinson’s disease and other diseases, but also mood problems and behavior problems.

Enough energy means a happy and healthy life. It also reflects in our brains with focused and sharp thinking. Lack of energy means mood problems, dementia, and slowed mental function among others. Mitochondria are intricately linked to the ability of the prefrontal cortex –our brain’s captain- to come fully online. Brain cells are loaded in mitochondria that produce the necessary energy to learn and memorize, and fire neurons harmoniously.

The sirtuin family of genes works by protecting and improving the health and function of your mitochondria.[10] They are positively influenced by a diet that is non-glycating, i.e. a low carb diet as opposed to a high carb diet which induces mitochondrial dysfunction and formation of reactive oxygen species.

Another thing that contributes to mitochondrial dysfunction is latent viral infection such as the ones of the herpes family. As I mentioned in On Viral “Junk” DNA, a DNA Enhancing Ketogenic Diet, and Cometary Kicks, most, if not all of your “junk” DNA has viral-like properties. If a pathogenic virus takes hold of our DNA or RNA, it could lead to disease or cancer.

Herpes simplex virus is a widespread human pathogen and it goes right after our mitochondrial DNA. Herpes simplex virus establishes its latency in sensory neurons, a type of cell that is highly sensitive to the pathological effects of mt DNA damage.[11] A latent viral infection might be driving the brain cell loss in neurodegenerative diseases such as Alzheimer’s disease.[12]As I speculated in Heart attacks, CFS, herpes virus infection and the vagus nerve , a latent herpes virus infection might drive more diseases than we would like to admit.

Members of the herpes virus family (i.e. cytomegalovirus and Epstein-Barr virus which most people have as latent infections!), can go after our mitochondrial DNA, causing neurodegenerative diseases by mitochondrial dysfunction. But a ketogenic diet is the one thing that would help stabilize mtDNA since mitochondria runs the best on fat fuel. As it happens, Alzheimer’s disease is the one condition where a ketogenic diet has its most potential healing effect.[4]

The role of mitochondrial dysfunction in our “modern” age maladies is a staggering one. Optimal energetic sources are essential if we are to heal from chronic ailments. It is our mitochondria which lies at the interface between the fuel from foods that come from our environment and our bodies’ energy demands. And it is a metabolism based on fat fuel, a ketone metabolism, the one which signals epigenetic changes that maximizes energetic output within our mitochondria and help us heal.

I am incredulous at how my body is responding.  I think I am totally carb intolerant.  I’ve struggled with extreme fatigue/exhaustion for so many years, even with improved sleep in a dark room that I can’t tell you how wonderful it is to wake up in the morning, get out of bed and not long to crawl back in, going through the day by will mostly.  Also chronic long-standing intestinal issues are finally resolving.  A couple of people at work have made comments to the effect that I’m a “different woman”, calmer, no more hyperness under pressure, stress seems to roll off of my back as well.  I’ve lost a little weight and although I don’t weigh myself, my clothes are definitely looser.  I’ve had the round middle for so many years I was resigned to struggling to bend over to pull my shoes on!  -Bluefyre, 56 years old, United States. Sott.net forum

 

Ketosis – Closer Look

The presence of ketones in the blood and urine, a condition known as ketosis, has always been regarded as a negative situation, related to starvation. While it is true that ketones are produced during fasting, ketones are also produced in times of plenty, but not plenty of carbohydrates since a carb metabolism suppresses ketosis. In the absence of most carbs in the diet, ketones will form from fat to supply for energy. This is true even if lots of fats and enough protein are eaten, something that is hardly a starvation condition.

As we already saw, a ketogenic diet has been proved useful in a number of diseases, especially neurological ones. Strictly speaking, a ketogenic diet is a high fat diet in which carbohydrates are either completely eliminated or nearly eliminated so that the body has the very bare minimum sources of glucose. That makes fats (fatty acids) a mandatory energetic fuel source for both the brain and other organs and tissues. If you are carb intake is high, you’ll end up storing both the fat and the carbs in your fat tissue thanks to the hormone insulin. A ketogenic diet is not a high protein diet, which as it happens, can also stimulate insulin. It is basically a diet where you rely primarily on animal foods and especially their fats.

I recently had my annual blood work done (cholesterol, etc.) During the review, my doctor said that everything looked great! He then encouraged me to continue on my great ‘low fat, high fruit and veggie diet’ that I must be following! I just smiled. Next visit I’m going to tell him about my real ‘diet’. Lol  -1984, United States. Sott.net forum.

 

Among the by-products of fat burning metabolism are the so called ketone bodies – acetoacetate, β-hydroxybutyrate and acetone – which are produced for the most part by the liver. When our bodies are running primarily on fats, large amounts of acetyl-CoA are produced which exceed the capacity of the Krebs cycle, leading to the making of these three ketone bodies within liver mitochondria. Our levels of ketone bodies in our blood go up and the brain readily uses them for energetic purposes. Ketone bodies cross the blood brain barrier very readily. Their solubility also makes them easily transportable by the blood to other organs and tissues. When ketone bodies are used as energy, they release acetyl-CoA which then goes to the Krebs cycle again to produce energy.

In children who were treated with the ketogenic diet to treat their epilepsy, it was seen that they become seizure-free even long after the diet ended, meaning that not only did the diet proved to be protective, but also it modified the activity of the disease , something that no drug has been able to do.[13] In Alzheimer’s disease, as levels of ketone bodies rise, memory improves. People’s starved brains finally receive the much needed fats they need! In fact, every single neurological disease is improved on the ketogenic diet.

The benefits of a ketogenic diet can be seen as fast as one week, developing gradually over a period of 3 weeks. There are several changes in gene expression involving metabolism, growth, development, and homeostasis among others.

The hippocampus is a region in your brain that is very vulnerable to stress which makes it lose its brain cells. The hippocampus has to do with memory, learning, and emotion. As it happens, a ketogenic diet promotes the codification of genes which creates mitochondria in the hippocampus, making more energy available. A larger mitochondrial load and more energy means more reserve to withstand much more stress.[14]

In some animal models, there is a 50% increase in the total number of mitochondria in the hippocampus, resulting in more brain ATP.[15] Other animal studies show how communication between brain cells in the hippocampus would remain smooth for 60% longer when exposed to a stressful stimulus compared to their counterparts who didn’t had a ketogenic diet.[16] This is very important since too much stress can damage the hippocampus and its capacity to retrieve information, making you “absent-minded” or “brain-scattered”, as well as affecting the ability of your prefrontal cortex to think and manage behavior.

A ketogenic diet also increases levels of the calming neurotransmitter – GABA which then serves to calm down the overexcitation which is at the base of major neurodegenerative diseases, but also anxiety and other mood problems. A ketogenic diet also increases antioxidant pathways that level the excess production of free radicals from a toxic environment. It also enhances anti-inflammatory pathways.

Ketosis also cleans our cells from proteins that act like “debris” and which contribute to aging by disrupting a proper functioning of the cell.[17] It basically does this by what is known as autophagy which preserves the health of cells and tissues by replacing outdated and damaged cellular components with fresh ones. This prevents degenerative diseases, aging, cancer, and protects you against microbial infections.A ketogenic diet not only rejuvenates you, it also makes a person much less susceptible to viruses and bacterial infections.[18] This is very relevant due to the increasing number of weird viral and bacterial infections that seem to be incoming from our upper atmosphere[19] (for more information see New Light on the Black Death: The Viral and Cosmic Connection), or due to high levels of radiation that creates more pathogenic strains (see Detoxify or Die: Natural Radiation Protection Therapies for Coping With the Fallout of the Fukushima Nuclear Meltdown). Either or, we are more vulnerable than ever due to the state of our mitochondria. But we can prepare for the worst with ketosis.

Ketone-enhanced autophagy is very important because autophagy can target viruses and bacteria that grow inside cells which are very problematical.[20] Intracellular viruses and bacteria can lead to severe mitochondrial dysfunction and ketosis remains by far our best chance against them.

Ketone bodies production through intermittent fasting and the ketogenic diet is the most promising treatment for mitochondrial dysfunction.[21]The longevity benefits seen caloric restriction research is due to the fact that our bodies shift to a fat burning metabolism within our mitochondria. With a ketogenic diet, we go into a fat burning metabolism without restricting our caloric intake.

Ketosis deals effectively with all the problems of a diet rich in carbs – the one recommended by mainstream science: anxiety, food cravings, irritability, tremors, and mood problems among others. It is a crime to discourage the consumption of a high fat diet considering that a ketogenic diet shrinks tumors on human and animal models, and enhances our brain’s resiliency against stress and toxicity.

In addition to increasing the production of our body’s natural valium – GABA – the increased production of acetyl-CoA generated from the ketone bodies also drives the Krebs cycle to increase mitochondrial NADH (reduced nicotinamide adenine nucleotide) which our body uses in over 450 vital biochemical reactions – including the cell signaling and assisting of the ongoing DNA repair. Because the ketone body beta-hydroxybutyrate is more energy rich than pyruvate, it produces more ATP. Ketosis also enhances the production of important anti-oxidants that deal with toxic elements from our environments, including glutathione.

Mitochondria from the hippocampus of ketogenic diet-fed animals are also resistant to mtDNA damage and are much less likely to commit cell suicide –apoptosis- at inappropriate times.

As Douglas C. Wallace, PhD, Director of the Center for Mitochondrial and Epigenomic Medicine says, “the ketogenic diet may act at multiple levels: It may decrease excitatory neuronal activity, increase the expression of bioenergetic genes, increase mitochondrial biogenesis and oxidative energy production, and increase mitochondrial NADPH production, thus decreasing mitochondrial oxidative stress.”[21]

Keto-adaptation results in marked changes in how we construct and maintain optimum membrane (“mem-brain”) composition, not only because of the healthy fats we provide through the diet, but also because of less free radical production and inflammatory mediators, along with more production of anti-oxidants. It is really the ideal balanced state.

Moreover, you might want to keep in mind this excerpt from Human Brain Evolution: The Influence of Freshwater and Marine Food Resources[22]:

“There are two key advantages to having ketone bodies as the main alternative fuel to glucose for the human brain. First, humans normally have significant body fat stores, so there is an abundant supply of fatty acids to make ketones. Second, using ketones to meet part of the brain’s energy requirement when food availability is intermittent frees up some glucose for other uses and greatly reduces both the risk of detrimental muscle breakdown during glucose synthesis, as well as compromised function of other cells dependent on glucose, that is, red blood cells. One interesting attribute of ketone uptake by the brain is that it is four to five times faster in newborns and infants than in adults. Hence, in a sense, the efficient use of ketones by the infant brain means that it arguably has a better fuel reserve than the adult brain. Although the role of ketones as a fuel reserve is important, in infants, they are more than just a reserve brain fuel – they are also the main substrate for brain lipid synthesis.

I have hypothesized that evolution of a greater capacity to make ketones coevolved with human brain expansion. This increasing capacity was directly linked to evolving fatty acid reserves in body fat stores during fetal and neonatal development. To both expand brain size and increase its sophistication so remarkably would have required a reliable and copious energy supply for a very long period of time, probably at least a million, if not two million, years. Initially, and up to a point, the energy needs of a somewhat larger hominin brain could be met by glucose and short – term glucose reserves such as glycogen and glucose synthesis from amino acids. As hominins slowly began to evolve larger brains after having acquired a more secure and abundant food supply, further brain expansion would have depended on evolving significant fat stores and having reliable and rapid access to the fuel in those fat stores. Fat stores were necessary but were still not sufficient without a coincident increase in the capacity for ketogenesis. This unique combination of outstanding fuel store in body fat as well as rapid and abundant availability of ketones as a brain fuel that could seamlessly replace glucose was the key fuel reserve for expanding the hominin brain, a reserve that was apparently not available to other land – based mammals, including nonhuman primates.”

It is indisputable that a ketogenic diet has protective effects in our brains. With all the evidence of its efficacy in mitochondrial dysfunction, it can be applied for all of us living in a highly stressful and toxic environment. Ketone bodies are healing bodies that helped us evolve and nowadays our mitochondria are always busted in some way or another since the odds in this toxic world are against us. Obviously, there are going to be people with such damaged mtDNA or with mutations they were born with, who can’t modify their systems (i.e. defects on L-carnitine metabolism), but even in some of those cases, they can halt or slow down further damage. Our healthy ancestors never had to deal with the levels of toxicity that we live nowadays and nevertheless, they ate optimally. Considering our current time and environment, the least we can do is eat optimally for our physiology.

The way to have healing ketone bodies circulating in our blood stream is to do a high fat, restricted carb and moderated protein diet. Coupled with intermittent fasting which will enhance the production of ketone bodies, and resistance training which will create mitochondria with healthier mtDNA, we can beat the odds against us.

What is considered nowadays a “normal diet” is actually an aberration based on the corruption of science which benefits Big Agra and Big Pharma. If we would go back in time to the days before the modern diet became normalized by corporative and agricultural interests, we will find that ketosis was the normal metabolic state. Today’s human metabolic state is aberrant. It is time to change that.

References

[1] A research member of sott.net’s forum has diabetes type 1 and is doing the ketogenic diet. On normal circumstances, diabetics (including type I) report amazing results on a low-carbohydrate diet. See Dr. Bernstein’s Diabetics Solution by Richard K. Bernstein, MD (Little, Brown and Company: 2007).

[2] It varies among each person, but the general range is between 0 and 70 grams of carbs plus moderate intake of protein, between 0.8 and 1.5 grams of protein per kg of ideal body weight. Pregnant women and children should not have their protein restricted.

[3] Ketogenic diets in seizure control and neurologic disorders by Eric Kossoff, MD, Johns Hopkins Hospital, Baltimore, Maryland. The Art and Science of Low Carbohydrate Living by Jeff S. Volek, PhD, Rd and Stephen D. Phinney, MD, PhD. Beyond Obesity, LLC , 2011.

[4]A Paoli, A Rubini, J S Volek and K A Grimaldi. Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. European Journal of Clinical Nutrition (2013) 67, 789–796

[5] Rainer J Klement, Ulrike Kämmerer. Is there a role for carbohydrate restriction in the treatment and prevention of cancer? Nutr Metab (Lond). Oct 26, 2011; 8: 75.

[6] If the genetic code is the hardware for life, the epigenetic code is software that determines how the hardware behaves.

[7] David N. Ruskin and Susan A. Masino, The Nervous System and Metabolic Dysregulation: Emerging Evidence Converges on Ketogenic Diet Therapy. Front Neurosci. 2012; 6: 33.

[8] Finkel T, Hwang PM. The Krebs cycle meets the cell cycle: mitochondria and the G1-S transition. Proc Natl Acad Sci U S A. 2009 Jul 21;106(29):11825-6.


[9] Matthews C.M. Nurturing your divine feminine. Proc (Bayl Univ Med Cent). 2011 July; 24(3): 248.

[10] Hipkiss AR. Energy metabolism, altered proteins, sirtuins and ageing: converging mechanisms? Biogerontology. 2008 Feb;9(1):49-55.

[11] Saffran HA, Pare JM, Corcoran JA, et al. Herpes simplex virus eliminates host mitochondrial DNA. EMBO Rep. 2007 Feb;8(2):188-93.

[12] Porcellini E, Carbone I, et al. Alzheimer’s disease gene signature says: beware of brain viral infections. Immun Ageing. 2010 Dec 14;7:16.

[13] Gasior M, Rogawski MA, Hartman AL. Neuroprotective and disease-modifying effects of the ketogenic diet. Behav Pharmacol. 2006 Sep;17(5-6):431-9.

[14] Maalouf M, Rho JM, Mattson MP. The neuroprotective properties of calorie restriction, the ketogenic diet, and ketone bodies. Brain Res Rev. 2009 Mar;59(2):293-315.

[15] Nylen K, Velazquez JL. The effects of a ketogenic diet on ATP concentrations and the number of hippocampal mitochondria in Aldh5a1(-/-) mice. Biochim Biophys Acta. 2009 Mar;1790(3):208-12.

[16] Bough K. Energy metabolism as part of the anticonvulsant mechanism of the ketogenic diet. Epilepsia. 2008 Nov;49 Suppl 8:91-3.

[17] Finn PF, Dice JF. Ketone bodies stimulate chaperone-mediated autophagy. J Biol Chem. 2005 Jul 8;280(27):25864-70.

[18] Yuk JM, Yoshimori T, Jo EK. Autophagy and bacterial infectious diseases. Exp Mol Med. 2012 Feb 29;44(2):99-108.

[19] Chandra Wickramasinghe, Milton Wainwright & Jayant Narlika. SARS – a clue to its origins? The Lancet, vol. 361, May 23, 2003, pp 1832.

[20] Yordy B, Iwasaki A. Autophagy in the control and pathogenesis of viral infection. Curr Opin Virol. 2011 Sep;1(3):196-203.

[21] Douglas C. Wallace, Weiwei Fan, and Vincent Procaccio. Mitochondrial Energetics and Therapeutics Annu Rev Pathol. 2010; 5: 297–348.

[22] Stephen Cunnane, Kathlyn Stewart.Human Brain Evolution: The Influence of Freshwater and Marine Food Resources. June 2010, Wiley-Blackwell.

 


 

生酮或不生酮

  • 【專有名詞翻譯】
    Pyruvate=丙酮酸
    Acetyl CoA=乙醯輔酶A
    OAA=Oxaloacetate=草醯乙酸
    Citrate=檸檬酸
    AcAc=Acetoacetate=乙酰乙酸
    BHB=Beta-hydroxybutyrate=β-羥基丁酸
    Acetone=丙酮
    NAD+=Nicotinamide adenine dinucleotide=菸鹼醯胺腺嘌呤二核苷酸,是一種轉遞質子(更準確來說是氫離子)的輔酶,它出現在細胞很多代謝反應中。

【參考資料】


  • 根據下列生化途徑,Pyruvate會代謝成Acetyl CoA,Acetyl CoA會走二條路線,一條是進入克氏循環(圖右),一條是進入生酮路線(圖左)。

     

  • OAA的量決定身體是走生酮路線或是走克氏循環:
    OAA不足→生酮
    OAA充足→克氏循環(TCA)

  • OAA的食物來源是醣類或蛋白質。

  • 當OAA充足時,Acetyl CoA會結合OAA轉換成Citrate,然後進入克氏循環製造能量。實施低醣飲食者,Acetyl CoA的來源大多來自脂肪,接下來不管是走生酮路線或克氏循環,Acetyl CoA都會被分解掉,換句話說,實施低醣飲食,脂肪最後都會被燃燒掉。(編者補充:燃燒脂肪是減重者樂意看到的結果!)

  • 當OAA不足時,Acetyl CoA會走生酮路線,轉換成Acetoacetyl CoA,Acetoacetyl CoA再轉換成AcAc,接著,AcAc再繼續轉換成Acetone或BHB。這個BHB就是生酮飲食者渴望製造的酮體的主要成分,血酮機也是在測量它的濃度。

  • 斷食或低醣狀態下,OAA會被挪用到糖質新生作用,造成缺乏足夠的OAA來與Acetyl CoA一起推動克氏循環(TCA),最後Acetyl CoA只好改走生酮路線了。

  • AcAc是肝臟製造的,目前很難測量出它的濃度。

  • Acetone基本上可視為AcAc的揮發體,類似於指甲油的氣味(丙酮)。當Acetone呼出過多時,旁人會聞到水果氣味,自己嘴裡也會有金屬味。

  • Acetone在血液中很難測出,但是可以從呼吸中測出。Ketonix即是測量呼吸中的Acetone的機器。

  • 血液中BHB濃度的影響因素:
    脂肪攝取量
    血液總能量
    胰島素濃度
    NAD+/NADH比率
    BHB的使用率

  • 當NAD+不足或NADH過多→NAD+/NADH比值 變小。

  • NAD+/NADH比值較小時,AcAc會走生成BHB的路線。(編者補充:AcAc吸取能量後,才能轉換為BHB。BHB釋放能量後,才變成AcAc。從另一個角度來看,BHB是高階能源,AcAc次之。)

  • NAD+/NADH比值較大時,AcAc會走生成Acetone的路線。(編者補充:能量不足時,AcAc無法轉換成BHB,只能轉換成Acetone,從呼吸中揮發掉。)

  • NAD+會隨著年紀而減少。一些抗老化的研究都致力於提高NAD+的產量,例如:利用靜脈直接注射NAD+來治療毒癮或狂歡後用來迅速恢復體力。

  • 請參考→提高NAD+的方法

  • 當我們從食物中獲得能量時,NAD+會得到1個氫離子(H+)和2個電子,形成NADH。反之,當我們消耗能量時,NADH會減少,NAD+會增加。

  • 能量過剩會造成NADH增加,尤其是糖尿病,NADH會特別高,所以,NADH增加所產生的高濃度BHB與低濃度Acetone並不完全是理想狀態。

  • 第一型糖尿病患的特色:NAD+/NADH比率偏低,BHB特別高,高於8mmol/L,也就是所謂的酮症酸中毒(ketoacidosis),常常伴隨著很高濃度的血糖。

  • 非第一型糖尿病者,BHB都會低於4mmol/L。

  • BHB過高是很危險的,因為BHB是酸性的。

  • 大腦可以直接使用BHB當燃料,但是身體其他部位必須把BHB逆轉成AcAc才能利用。(編者補充:不太能懂大腦如何直接燃燒BHB,因為從酮體分解的生化途徑來看,BHB的燃燒一樣要逆轉回AcAc才能轉換成Acetyl CoA,進入TCA循環。)

  • 當血液總能量減少或NAD+/NADH比值較高時,身體才會開始把過剩的BHB逆轉成AcAc,供身體其他部位使用。這時候,血液中會有較多的AcAc與較少的BHB,呼吸中也會有較多的Acetone。反之,當血液總能量增加或NAD+/NADH比值較低時,血液中會出現較多的BHB,好處是:大腦有充沛的燃料。壞處是:胰島素會上升來處理這些過剩的能量,長期下來會造成胰島素抗阻及其他代謝症候群。

  • BHB可當作酮體儲存量的參考指標。
    Acetone可當作酮體消耗量的指標。

  • 脂肪大量減少的指標:呼吸中的Acetone濃度>血液中的酮體(BHB)濃度。

  • Acetoacetate與BHB的燃燒,請參考→酮體的生成與分解


 

酮體的生成與分解


  • 酮體有三種:

  1. 乙酰乙酸鹽(acetoacetate,簡稱AcAc)

  2. β-丁酸鹽-hydroxybutyrate,簡稱BHB,又稱為3-hydroxybutyrate或3-OH butyrate)

  3. 丙酮(acetone)

  • AcAc與BHB是主要的酮體,占大多數。
    acetone是次要的酮體,量極微。

  • 酮體的生成:acetyl CoA→acetoacetyl CoA→HMG CoA→acetoacetate→3-hydroxybutyrate + acetone(下圖左邊)

  • 酮體的分解:3-hydroxybutyrate→acetoacetate→acetoacetyl CoA→acetyl CoA→TCA cycle(下圖右邊)

  • 酮體之一的acetone無法逆轉回acetoacetate

  • acetoacetate→acetoacetyl CoA的燃燒分解路線不是走原來的生酮路線,無法經由HMG CoA逆轉回去,只能直接逆轉回acetoacetyl CoA。

  • acetoacetate→acetoacetyl CoA的步驟需要酵素acetoacetyl succinyl CoA transferase的幫忙才能成功,肝臟恰好缺乏這個酵素,所以肝臟只能生產酮體給其他組織,例如肌肉、大腦、心臟、腎上腺皮質,自己無法燃燒分解酮體。



  • AcAc→BHB是發生在細胞粒腺體內。(acetoacetate→3-OH butyrate)

  • 斷食或低醣狀態下,OAA會被挪用到糖質新生作用,造成缺乏足夠的OAA來與Acetyl CoA一起推動克氏循環(TCA),最後Acetyl CoA只好改走生酮路線了。


  • 產生酮體後,還是要燃燒掉,燃燒時酮體要先逆轉回Acetyl CoA,然後再跟OAA合作一起進入克氏循環(TCA)。結果繞了一圈還是需要OAA!那麼,要如何解決OAA不足的問題?
    1.從Pyruvate→OAA來轉換。而Pyruvate的來源除了葡萄糖外,也可以從胺基酸來轉換,例如:Alanine、Glycine、Threonine、Cysteine、Serine、Tryptophan。
    2.從Pyruvate→Malate→OAA來轉換。
    3.從PEP→OAA來轉換。
    4.從Aspertate、Asparagine→OAA來轉換。







     

  • 酮體生成的速率決定於3個主要酵素:
    1. hormonesensitive lipase (triglyceride lipase)
    2. acetyl CoA carboxylase (簡稱ACC)
    3. HMG CoA synthase

  • ACC會把acetyl CoA轉換成malonyl CoA,malonyl CoA的作用是促進脂肪酸的合成(如下圖ACC1的綠色箭頭),抑制脂肪酸進入粒線體內分解(如下圖ACC2的紅色箭頭)。

  • malonyl CoA會阻止脂肪酸進入粒線體(如上圖ACC2的紅色箭頭),只有當malonyl CoA的量較少時,脂肪酸才能順利進入粒線體分解,切成很多很多的acetyl CoA,而有了acetyl CoA之後才能進一步製造酮體。所以,malonyl CoA在酮體生成上扮演了很重要的角色。

  • hormonesensitive lipase與ACC都受到胰島素(insulin)、腎上腺素(epinephrine)、升糖激素(glucagon)的影響,其中,胰島素會抑制酮體的合成,腎上腺素)與升糖激素則是會促進酮體的合成。整個過程是:
    胰島素活化ACC→促進acetyl CoA轉換成malonyl CoA→malonyl CoA增加→促進脂肪酸合成(如上圖ACC1的綠色箭頭),抑制脂肪酸進入粒線體分解(如上圖ACC2的紅色箭頭)→酮體減少。(胰島素主能源儲存,抑制能源分解。)
    升糖激素抑制ACC→抑制acetyl CoA轉換成malonyl CoA→malonyl CoA減少→脂肪酸順利進入粒線體分解→酮體增加。
    簡單說就是,荷爾蒙控制ACC,ACC控制malonyl CoA,malonyl CoA控制脂肪的代謝,脂肪的代謝影響酮體的產量。

     

  • ACC磷酸化就失去了活性(見下圖),促進因素是AMP-activated protein kinase。
    ACC去掉磷酸就恢復了活性,促進因素是胰島素,抑制因素是升糖激素。
    ACC活化的結果就是促進脂肪酸合成,換句話說,胰島素會促進脂肪酸合成,阻止脂肪酸分解,相反地,升糖激素會抑制脂肪酸合成,促進脂肪酸分解。



     

  • ACC需要生物素(Biotin)的協助才能完成acetyl CoA→malonyl CoA。(脂肪合成)

 

 

 

Pyruvate的代謝

  • Pyruvate的命運:

  1. Pyruvate可以轉換成乳酸。(3碳→3碳)

     

  2. Pyruvate可以轉換成OAA (3碳→4碳),其中,Biotin是重要的輔助營養素。(除了Biotin之外,還需要錳、nicotinamide。見上圖。)
    OAA可以進一步轉換成胺基酸,或走糖質新生路線,或進入TCA循環。

     

  3. Pyruvate可以轉換成丙氨酸(Alanine)。(3碳→3碳)

     

  4. Pyruvate可以轉換成蘋果酸(Malate)。(3碳→3碳)

     

  5. Pyruvate可以轉換成乙醛、乙醇(酒精)、乙酸。(3碳→2碳)




     

  6. Pyruvate可以轉換成Acetyl CoA。(3碳→2碳)

  • 癌細胞的Pyruvate代謝。

 

 

 

PDH、PDC、PDP、PDK

  • Pyruvate轉換成Acetyl CoA的轉化酶是PDH ( Pyruvate dehydrogenase),它是一個酵素複合體,包括了三個酵素:PD E1、PD E2、PD E3,所以又稱為PDC ( Pyruvate dehydrogenase complex)。

  • PDC (Pyruvate dehydrogenase complex)包含三個酵素:
    PD E1=Pyruvate decarboxylase
    PD E2=Dihydrolipoamide acyltransferase
    PD E3=Dihydrolipoyl dehydrogenase

  • PDC (Pyruvate dehydrogenase complex)的二個調節酵素:
    1.活化酵素:PDP (PD phosphatase)
    2.抑制酵素:PDK (PD kinase)

  • PDC (Pyruvate dehydrogenase complex)的二個輔營養素:
    1.TPP (維生素B1的活性成分)
    2.Lipoic acid (硫辛酸)



     

  • PDC沒有磷酸化=活性狀態。
    PDC磷酸化=非活性的狀態。(下圖右側,PDC的其中一的酵素PD E1黏上3個磷酸就失去活性了。)

  • PDP可以把PDC去磷酸化,恢復其活性狀態。(PDP包括PDP1、PDP2。)
    PDK可以把PDC磷酸化,讓它失去活性。(PDK包括PDK1、PDK2、PDK3、PDK4。)

  • 活化PDP可以保持PDC的活性,促進Pyruvate→Acetyl CoA。
    活化PDK可以降低PDC的活性,阻止Pyruvate→Acetyl CoA。

    PDC

    PDC的功用

    Pyruvate→Acetyl CoA

    調節PDC的酵素

    PDP

    PDK

    調節酵素的作用

    活化PDC

    (紅色字體)

    抑制PDC

    (藍色字體)

    Acetyl CoA的產量

    增加

    減少

    malonyl CoA的產量

    增加

    減少

    脂肪酸的產量

    增加

    減少

    脂肪酸的分解 減少 增加

    acetyl CoA carboxylase的功用

    Acetyl CoA→malonyl CoA

    malonyl CoA的作用

    • malonyl CoA→Fatty acids

    • 促進脂肪酸的合成

    • 抑制脂肪酸的分解

    • 阻止脂肪酸進入粒線體內進行β-Oxidation

    PDC間接影響脂肪酸的合成與分解 Pyruvate→Acetyl CoA→malonyl CoA→Fatty acids

    燃料傾向

    燃糖

    燃脂

    活化因子

    活化PDP:
    鈣離子、鎂離子、Insulin

    活化PDK:
    Acetyl CoA、ATP、NADH、Glucose、脂肪酸

    癌症、缺氧

    抑制因子

    抑制PD E1:

    NADH、ATP


    抑制TPP
    缺乏BI、酒精(損耗大量B1)

    抑制PDK:

    Pyruvate、ADP、NAD、DCA、Insulin、lipoic acid、DCA

     

    PDK調控能源的切換

    • Glucose→Pyruvate→Acetyl CoA→malonyl CoA→Fatty acids

    • PDC在飽食狀態下比較活躍,飢餓狀態下比較不活躍。

    • 當飢餓或葡萄糖缺乏時,身體會透過PDK的調控因子來強化PDK,間接抑制PDC的作用,讓葡萄糖的分解減少,保留較多的葡萄糖給專屬細胞使用,同時Acetyl CoA產量減少後,malonyl CoA的產量也會減少,抑制脂肪酸的分解作用也會減弱,能源由燃燒葡萄糖轉向燃燒脂肪酸。相反地,也可以透過PDK的調控因子來抑制PDK,間接活化PDC的作用,產生較多的Acetyl CoA去合成malonyl CoA,然後再透過malonyl CoA去促進脂肪酸合成與抑制脂肪酸分解。

    • 利用PDK來抑制Pyruvate→Acetyl CoA,可以保留較多不被轉換的Pyruvate,接著Pyruvate可以再轉換成其他化合物,例如:乳酸、OAA、alanine、Mallate、乙醛、酒精。請參考→Pyruvate的代謝)。另外,Pyruvate也可以逆轉合成葡萄糖。

    • Darren Schmidt認為,pyruvate的代謝途徑只有進入粒線體內走pyruvate→Acetyl CoA→TCA這條途徑燃燒最乾淨(有氧燃燒),未進入粒線體的其他的途徑都會產生酸性代謝物(無氧發酵),例如:乳酸、乙醛、乙醇、乙酸。

    • 標靶藥物的設計原理之一:
      如果某種藥物可以抑制PDK,Pyruvate就能充分轉換成Acetyl CoA,然後進入TCA循環,充分燃燒製造能源。反之,如果PDK沒有被抑制,PDK就會阻止Pyruvate轉換成Acetyl CoA,造成Pyruvate過剩,然後被癌細胞轉換成Lactate與Alanine,接著Lactate與Alanine再被肝臟轉換為葡萄糖來餵養癌細胞,形成惡性循環,這就是所謂的惡質病(Cachexia)。

    • Pyruvate←→Lactate、Alanine(雙向)

    • Glucose→Pyruvate→Lactate→Pyruvate→Glucose
      Glucose→Pyruvate→Alanine→Pyruvate→Glucose




















     

  • 活化PDK4的因子→抑制PDC→增加燃燒脂肪,減少燃燒葡萄糖:(如下圖)
    肌肉:斷食、脂肪酸、運動、高脂飲食。(胰島素抑制PDK4)
    脂肪組職:腎上腺素、TZD。
    心臟:高脂飲食。
    肝臟:脂肪肝、甲狀腺素、生長荷爾蒙、甲狀腺素。(Metformin間接抑制PDK4)

  • 了解PDK在不同組織的各種調控因子才能設計出有效的療法。

     

  • 調節PDK的基因與轉譯因子:


 

 

TCA循環

  • TCA循環(Tricarboxylic acid cycle)又名檸檬酸循環(Citric acid cycle)。

  • Acetyl CoA與OAA一起合成citrate,進入TCA循環。



     

  • 生化反應需要輔助營養素來推動。



     

  • 各種胺基酸可以轉換成TCA的各種成分,除了能製造能量ATP之外,還能經由OAA轉換成葡萄糖,進行所謂的糖質新生。









     

  • 代謝途徑大串聯