Case not yet made for high-fat dairy

If you’re interested in the intersection between food and health, the Nutrition Action Newsletter is a gem. They always seem to be focussing on the issue that I’ve been thinking about with its usual blend of facts and skepticism. Here’s an example.

http://www.nutritionaction.com/daily/what-to-eat/can-high-fat-dairy-help-keep-a-lid-on-your-blood-sugar/?

Can high-fat dairy help keep a lid on your blood sugar?

“The case against low-fat milk is stronger than ever,” said TIME.com.

The evidence cited by TIME: In a study that tracked roughly 3,000 people for 15 years, those with higher levels of dairy fats in their blood had about a 45 percent lower risk of getting diabetes.

What might explain that link?

“People eating more high fat dairy products will have enough calories so they won’t feel hungry enough to need additional calories from sugary foods,” suggested TIME.

“It’s also possible that the fats in dairy may be acting directly on cells, working on the liver and muscle to improve their ability to break down sugar from food.”

Then again, something entirely different about people with higher blood levels of dairy fat might explain their lower risk of diabetes.

“They may have a healthier diet and lifestyle,” says Alice H. Lichtenstein, director of the cardiovascular nutrition laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. Or they may eat a lot of lower-fat dairy.

What trials of high-fat and low-fat dairy have found

Two recent studies—both partly funded by the dairy industry—gave people high-fat or low-fat dairy to see if either kept blood sugar in check.

One team studied people with the metabolic syndrome, who have an increased risk of type 2 diabetes and often have higher-than-normal blood sugar levels.

The scientists randomly assigned 72 of them to eat roughly three servings a day of low-fat dairy, three servings a day of high-fat dairy, or not much dairy (no more than three servings a week of fat-free milk and no other dairy foods).

After 12 weeks, insulin sensitivity got worse on both high-dairy diets. That is, extra dairy—full-fat or low-fat—made insulin less able to admit blood sugar into cells.

“It doesn’t appear that dairy has a beneficial impact on blood sugar levels,” says Lichtenstein.

What’s more, the high-fat-dairy group gained two pounds.

“We hear the argument that full-fat dairy increases satiety more than low- and non-fat dairy, but we don’t have data to support that,” says Lichtenstein.

In a similar study, another team randomly assigned 111 people with type 2 diabetes to one of three groups: high-fat dairy, low-fat dairy, or not much dairy.

After 24 weeks, blood sugar levels didn’t go up (not surprising, given that nearly all the participants were taking drugs to treat diabetes) or down (which must have disappointed the industry funder).

Bottom Line

“I don’t think there’s any credible evidence at this point to recommend high-fat dairy products to control blood glucose levels or weight,” says Lichtenstein.

Photo: chinnarach/stock.adobe.com.

The information in this post first appeared in the March 2021 issue of Nutrition Action Healthletter.

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