脂毒性：饱和脂肪如何升高血糖
Greger （格雷格）医生笔记：
这是三个系列视频的第三部分，从“什么原因导致胰岛素抵抗？”开始，然后是“溢出效应将肥胖症与糖尿病联系起来”。 我希望我可以将它们全部整合到一个视频中，但这会太长。
This is the third of a three-part series, starting with What Causes Insulin Resistance? and The Spillover Effect Links Obesity to Diabetes. I wish I could have fit it all into one video, but it would have just been too long.
糖尿病系列视频之二：肥胖症与糖尿病有啥关系？溢出效应又是怎么一回事？
本视频由Michael Greger医生于2015年2月9日发布，来自NutritionFacts.org — 能救命的营养学。
Michael Greger 医生是畅销书《How Not to Die》一书作者，中文译本：繁体版书名为《食疗圣经》。简体版书名为《救命》，将于今年5月底出版。
“脂毒性：饱和脂肪如何升高血糖”
Lipotoxicity: How Saturated Fat Raises Blood Sugar
摘要：采取植物性饮食的人的肌肉细胞脂肪堆积较少，且胰岛素抵抗较少的原因可能是因为饱和脂肪似乎最能削弱血糖控制。
The reason those eating plant-based diets have less fat buildup in their muscle cells and less insulin resistance may be because saturated fats appear to impair blood sugar control the most.
https://v.qq.com/txp/iframe/player.html?vid=n065013aknb&width=500&height=375&auto=0
脂肪和胰岛素抵抗之间的关联现在被广泛接受 — 所谓的异位脂肪堆积 — 脂肪堆积在它不应该存在的地方，比如在我们的肌肉细胞内。
The association between fat and insulin resistance is now widely accepted – so-called ectopic fat accumulation – the accumulation of fat in places it’s not supposed to be, like within our muscle cells.
但并非所有的脂肪都会同等地影响肌肉。
But not all fats affect muscles the same.
脂肪的类型 —饱和或不饱和 — 是至关重要的。
The type of fat – saturated or unsaturated – is critical.
饱和脂肪酸，如棕榈酸，主要存在于肉类，乳制品和鸡蛋中，引起胰岛素抵抗，但油酸主要存在于坚果，橄榄和牛油果中，可能实际上改善了胰岛素敏感性。
Saturated fats like palmitate, found mostly in meat, dairy, and eggs, cause insulin resistance, but oleate, found mostly in nuts, olives, and avocados may actually improve insulin sensitivity.
什么原因造成饱和脂肪不好呢？
What makes saturated fat bad?
饱和脂肪会导致更多的这些有毒降解产物和线粒体功能障碍，并增加氧化应激，自由基和炎症，从而造成一个恶性循环，其中饱和脂肪诱导的自由基引起肌肉细胞内的小型发电厂障碍，这导致自由基产生的增加和胰岛素信号传导的损害。
Saturated fat causes more of those toxic breakdown products and mitochondrial dysfunction, and increases oxidative stress, free radicals, and inflammation, establishing a vicious cycle of events in which saturated fat-induced free radicals cause dysfunction in the little power plants within our muscle cells, which causes an increase in free radical production and the impairment of insulin signaling.
充满饱和脂肪的脂肪细胞在很大程度上激活炎症反应。
Fat cells filled with saturated fat activate an inflammatory response to a far greater extent.
这种增加的炎症，伴随进食更多的饱和脂肪，已证明可通过自由基和神经酰胺的生成来提高胰岛素抵抗。
This increased inflammation, along with eating more saturated fat, has been demonstrated to raise insulin resistance through free radical and ceramide production.
饱和脂肪也被证明对骨骼肌胰岛素抵抗有直接作用。
Saturated fat has also been shown to have a direct effect on skeletal muscle insulin resistance.
饱和脂肪的积累增加了肌肉中甘油二酯的含量，这已被证明对肌肉胰岛素抵抗有很强的作用。无论血液中的脂肪是来自我们自己的脂肪还是来自动物的脂肪，结果都一样。
Accumulation of saturated fat increases the amount of diacylglycerol in the muscles, which has been demonstrated to have a potent effect on muscle insulin resistance. It doesn’t matter if the fat in our blood comes from our own fat, or from their fat.
您可以从人身上进行肌肉活组织检查，并将肌肉中饱和脂肪堆积与胰岛素抵抗相关联。
You can take muscle biopsies from people and correlate the saturated fat buildup in their muscles with insulin resistance.
虽然单不饱和脂肪更有可能被解毒或安全储存，但饱和脂肪会产生这些有毒的分解产物，如神经酰胺，会导致脂毒性。
While monounsaturated fats are more likely to be detoxified or safely stored away, saturated fats create these toxic breakdown products, like ceramide, that cause lipotoxicity.
Lipo - 意为脂肪，“liposuction”(吸脂)里的“lipo”(脂)字，以及“toxicity”(毒性)。（译注：这句话是解释英文“lipotoxicity”脂毒性这个词的构成。）肌肉中的这种脂肪毒性是解释引发胰岛素抵抗的众所周知的概念。
Lipo- meaning fat, as in liposuction, and toxicity. This fat toxicity in our muscles is a well-known concept in the explanation of the trigger for insulin resistance.
我已经谈到了饱和脂肪和反式脂肪对其他疾病的发展有促进作用，例如：自身免疫性疾病，癌症和心脏病等，但它们也会引起胰岛素抵抗，这是糖尿病前期和2型糖尿病的根本原因。
I’ve talked about the role saturated and trans fats contribute to the progression of other diseases, like autoimmune diseases, cancer, and heart disease, but they can also cause insulin resistance, the underlying cause of prediabetes and type 2 diabetes.
在人类饮食中，饱和脂肪来自动物，而反式脂肪来源于肉类和牛奶，此外还有部分氢化和精炼植物油。
In the human diet, saturated fats are derived from animal sources while trans fats originate in meat and milk, in addition to partially hydrogenated and refined vegetable oils.
这就是为什么通过实验将人们从动物脂肪转移到植物脂肪可以改善胰岛素敏感性。
That’s why experimentally shifting people from animal fats to plant fats can improve insulin sensitivity.
胰岛素的敏感性被添加乳脂的饮食削弱， 但饮食中添加橄榄中的脂肪，胰岛素敏感性不会被削弱。
Insulin sensitivity was impaired on the diet with added butterfat, but not on the diet with added olive fat.
我们知道肌肉长时间暴露于高水平的脂肪导致严重的胰岛素抵抗，饱和脂肪被证明是最差的。
We know prolonged exposure of our muscles to high levels of fat leads to severe insulin resistance, with saturated fats demonstrated to be the worst.
而且饱和脂肪不仅会导致抑制胰岛素信号传导、激活炎症途径以及增加自由基。
But they don’t just lead to inhibition of insulin signaling, the activation of inflammatory pathways, and the increase in free radicals.
饱和脂肪还引起基因表达的改变，导致关键线粒体酶的抑制，例如肉碱棕榈酰转移酶— 这最终解决了此疑惑，即为什么素食者具有高60％的脂肪燃烧酶。 他们吃的饱和脂肪较少。
They cause an alteration in gene expression, leading to a suppression of key mitochondrial enzymes, like carnitine palmitoyltransferase – which finally solves the mystery of why those eating vegetarian have a 60% higher expression of that fat-burning enzyme. They’re eating less saturated fat.
那么那些以植物性饮食为基础的人有较少的脂肪堵塞肌肉，胰岛素抵抗也更少吗？
So do those eating plant-based diets have less fat clogging their muscles and less insulin resistance too?
之前还没有关于那些吃纯素或素食者的胰岛素敏感性或肌肉内细胞脂肪的数据，直到这个研究出现。
There hasn’t been any data available regarding the insulin sensitivity or inside-muscle cell-fat of those eating vegan or vegetarian, until now.
伦敦帝国理工学院的研究人员比较了素食者与杂食者的胰岛素抵抗和肌肉脂肪。
Researchers at the Imperial College of London compared the insulin resistance and muscle fat of vegans versus omnivores.
那些吃植物性饮食的人具有非常苗条的不公平优势，因此他们找到与纯素者一样瘦的杂食者，以查看植物性饮食是否具有直接益处，为了与通过帮助人们减肥而从肌肉中间接去除脂肪进行比较。
Now those eating plant-based diets have the unfair advantage of being so much slimmer, so they found omnivores who were as skinny as vegans to see if plant-based diets had a direct benefit, as opposed to indirectly pulling fat out of the muscles by helping people lose weight in general.
他们发现纯素者肌肉细胞中的脂肪少得多，与体重相同的杂食者相比。
They found significantly less fat trapped in the muscle cells of vegans compared to omnivores even at the same body weight.
他们发现纯素者有更好的胰岛素敏感性，更好的血糖和更好的胰岛素水平，并且令人兴奋是显着改善了β细胞功能— 胰腺中首先制造胰岛素的细胞。
They found better insulin sensitivity, better blood sugar levels, better insulin levels, and, excitingly, significantly improved beta-cell function – the cells in the pancreas that make insulin in the first place.
他们得出结论， 吃纯素不仅预期具有心脏保护作用，有助于预防我们的＃1杀手 —心脏病 —并且素食主义也可能对β细胞有保护作用，也有助于预防我们的第七大死因— 糖尿病。
They conclude that eating vegan is not only expected to be cardioprotective, helping prevent our #1 killer – heart disease – but that veganism may be beta cell protective as well, helping also to prevent our seventh leading cause of death – diabetes.
参考文献：
L M Sparks. H Xie, R A Koza, R Mynatt, M W Hulver, G A Bray, S R Smith. A high-fat diet coordinately downregulates genes required for mitochondrial oxidative phosphorylation in skeletal muscle. Diabetes. 2005 Jul;54(7):1926-33.
W J Evans. Oxygen-carrying proteins in meat and risk of diabetes mellitus. JAMA Intern Med. 2013 Jul 22;173(14):1335-6.
D Estadella, C M da Penha Oller do Nascimento, L M Oyama, E B Ribeiro, A R Damaso, A de Piano. Lipotoxicity: effects of dietary saturated and transfatty acids. Mediators Inflamm. 2013; Epub 2013 Jan 31.
L M Goff, J D Bell, P W So, A Dornhorst, G S Frost. Veganism and its relationship with insulin resistance and intramyocellular lipid. Eur J Clin Nutr. 2005 Feb;59(2):291-8.
G Perseghin, P Scifo, F De Cobelli, E Pagliato, A Battezzati, C Arcelloni, A Vanzulli, G Testolin, G Pozza, A Del Maschio, L Luzi. Intramyocellular triglyceride content is a determinant of in vivo insulin resistance in humans: a 1H-13C nuclear magnetic resonance spectroscopy assessment in offspring of type 2 diabetic parents. Diabetes. 1999 Aug;48(8):1600-6.
B Vessby, M Uusitupa, K Hermansen, G Riccardi, AA Rivellese, L C Tapsell, C Nalsen, L Berglund, A Louheranta, B M Rasmussen, G D Calvert, A Maffetone, E Pedersen, I B Gustafsson, L H Storlien, KANWU Study. Substituting dietary saturated for monounsaturated fat impairs insulin sensitivity in healthy men and women: The KANWU Study. Diabetologia. 2001 Mar;44(3):312-9.
J Gojda, J Patkova, M Jacek, J Potockova, J Trnka, P Kraml, M Andel. Higher insulin sensitivity in vegans is not associated with higher mitochondrial density. Eur J Clin Nutr. 2013 Dec;67(12):1310-5.
C J Nolan, C Z Larter. Lipotoxicity: why do saturated fatty acids cause and monounsaturates protect against it? J Gastroenterol Hepatol. 2009 May;24(5):703-6.
J Ye. Role of insulin in the pathogenesis of free fatty acid-induced insulin resistance in skeletal muscle. Endocr Metab Immune Disord Drug Targets. 2007 Mar;7(1):65-74.
E W Kraegen, G J Cooney. Free fatty acids and skeletal muscle insulin resistance. Curr Opin Lipidol. 2008 Jun;19(3):235-41.
V T Samuel, G I Shulman. Mechanisms for insulin resistance: common threads and missing links. Cell. 2012 Mar 2;148(5):852-71.
A R Martins, R T Nachbar, R Gorjao, M A Vinolo, W T Festuccia, R H Lambertucci, M F Cury-Boaventura, L R Silveira, R Curi, S M Hirabara. Mechanisms underlying skeletal muscle insulin resistance induced by fatty acids: importance of the mitochondrial function. Lipids Health Dis. 2012 Feb 23;11:30.
H Karlic, D Schuster, F Varga, G Klindert, A Lapin, A Haslberger, M Handschur. Vegetarian diet affects genes of oxidative metabolism and collagen synthesis. Ann Nutr Metab. 2008;53(1):29-32.
编译者后记：您三个视频都看完了吗？现在清楚什么样的食物对身体有伤害了吗？Greger （格雷格）医生还制作了更多关于糖尿病的视频:
如何避免由糖尿病前期转为糖尿病？
用食物逆转糖尿病
糖尿病视网膜病变可以逆转吗？
鸡蛋 & 糖尿病
鱼 & 糖尿病
等等，Greger 医生制作的小视频涵盖营养与疾病的方方面面，您对哪方面感兴趣？欢迎加入“蔬食益生微信交流群”。
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