How Does Oatmeal Help With Blood Sugar?

How Does Oatmeal Help With Blood Sugar?
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Michael Greger
5/1/2023
Updated:
5/1/2023
0:00

The prebiotic fiber in oats helps to explain why oatmeal can improve diabetic control.

It is now widely accepted that diets high in animal fat and processed foods are major risk factors for developing type 2 diabetes. And it’s not just animal fat, but animal protein intake intensifies insulin resistance, which predisposes people to type 2 diabetes. No wonder studies have shown that elevated consumption of animal products and low intake of unprocessed plant foods increases the risk of not only cardiovascular disease but also diabetes. But of all the whole plant foods to pick from, why choose oatmeal to treat diabetes, which, as I discussed in my last video, was used to treat diabetes before insulin was discovered?

We’ve long known that higher consumption of whole grains, including oats, is associated with a lower risk of diabetes. But you don’t know until you put it to the test. There have been over a dozen randomized, controlled trials looking at the metabolic effects of oats intake in patients with type 2 diabetes. Oats were found to significantly improve both short-term and long-term blood sugar control and lower cholesterol levels. We think the benefits arise from a fermentable fiber in oats called beta-glucan because you can get a cholesterol-lowering effect even if you just eat the oat fiber straight—as well as an improvement in blood sugar control and insulin sensitivity in both types 1 and 2 diabetes. How exactly does the fiber do that? Well, we know one of the underlying cholesterol-lowering mechanisms of oatmeal consumption might be its microbiome-manipulating ability—in other words, its beneficial effect on our intestinal bacteria.

A little fiber goes a long way. Here, they were talking about the anti-inflammatory effects of the short-chain fatty acids that our good gut flora make from fiber. There are dozens of randomized, controlled trials showing the types of fiber found in oats and beans can improve long-term blood sugar control in diabetics—in fact, nearly double the U.S. Food and Drug Administration (FDA) threshold required for new blood sugar-lowering drugs. Why? Because the gut bacteria selectively promoted by dietary fiber intake can help alleviate type 2 diabetes.

In fact, based on 50 distinct bacterial markers in feces, you can tell who does and does not have diabetes. But change your diet, and you can change your gut flora within one day. We feed the flora fiber, and in return, they feed us right back these short-chain fatty acids, like butyrate, that have all these wonderful effects. Put people on a diet packed with oats, beans, fruits, vegetables, and nuts, and the number of fiber-feeders churning out the beneficial short-chain fatty acids shoots up, and fasting diabetic blood sugars drop about 25 percent within one month. And the more fiber-feeders fostered, the better the blood sugar control. When the fiber-promoted short-chain fatty acid producers were present in greater diversity and abundance, participants had improved hemoglobin A1c levels (a measure of longer-term blood sugar control). Then, before-and-after fecal transplant studies helped nail down cause and effect.

Oat fiber has been shown to act as a prebiotic, boosting the growth of beneficial bacteria like Lactobacillus and Bifidobacteria. So between the lack of animal protein and fat and bursting at the seams with prebiotic fiber, it’s no wonder that oatmeal diets grew to become part of the clinical routine in treating diabetes. Unfortunately, however, this practice has become increasingly neglected over time, a disappearance that’s been compared to the fate of unpopular theories in successive editions of Soviet encyclopedias.

Despite advances in therapy, we still have many people with poorly controlled diabetes. Thankfully this forgotten tool is back. I’ll review all the new oatmeal diet studies next.

Republished from NutritionFacts.org
Michael Greger, MD, FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. He has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on “The Dr. Oz Show” and “The Colbert Report,” and was invited as an expert witness in defense of Oprah Winfrey at the infamous “meat defamation” trial. This article was originally published on NutritionFacts.org
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