Sunday, April 08, 2012

Blood Glucose And Insulin Higher After Meal High In Saturated Fat

One more study finds meals high in saturated fat are not good for insulin resistance and diabetes:
PUFAs Acutely Affect Triacylglycerol-Derived Skeletal Muscle Fatty Acid Uptake And Increase Postprandial Insulin Sensitivity, American Journal of Clinical Nutrition, April 2012

It was a small study in men who were obese and already insulin resistant. It compared 3 diets - high in either saturated fat (SFA), monounsaturated fat (MUFA), or polyunsaturated fat (PUFA). Blood glucose and insulin were significantly higher after the saturated fat meal than the PUFA meal.

Interesting that the PUFA meal led to higher circulating fatty acids. Resistant starch does this too, except by a different mechanism - colonic bacteria eat undigested (resistant) starch, producing fatty acids that we absorb. These fatty acids are linked to improvement in sensitivity to insulin.

The evidence for the role of fat - not just quantity of fat, but also type of fat - in the diet is growing. The more total fat and the more saturated fat one eats, the greater the risk for developing insulin resistance and diabetes, as I've seen. It's not an intuitive relationship. I first wrote about it in 2008:
Type Of Fat Eaten Affects Insulin Levels

The KANWU study found that insulin resistance worsened on a high saturated fat diet (but improved on a MUFA diet). And I summarized 3 large epidemiological studies that implicated saturated fat in the development of diabetes.

The best sources of saturated fat in our diets are dairy products (cheese, butter, cream and the like) and animal foods. The fat in plants tends to be more unsaturated, PUFA and MUFA.


Bix said...

I think the presence of highly refined, high-glycemic index carbohydrates makes this association worse. Just my 2 cents. It's why diets that reduce all carbs could mask the effect the fat is having intramuscularly.

Anonymous said...

You need to show this to all the people who are saying saturated fat is good for you.

Pronutritioinist said...

There is more fresh evidence in AJCN online. Sunflower oil outperformed butter in head to head trial in terms of liver fat, inflammation (!) and cholesterol. Bjerme et al. 2012.

Bix said...

Well, that's interesting, Pronutritionist...

I thought that omega-6 would increase inflammatory markers. But they found:

"Compared with SFA [saturated fat] intake, n−6 PUFAs [omega-6 polyunsaturated fat] reduce liver fat and modestly improve metabolic status, without weight loss. A high n−6 PUFA intake does not cause any signs of inflammation or oxidative stress."

Thanks for that!