Researchers say they’ve discovered a direct link between blood sugar and gut bacteria and have thereby achieved success in treating a small group of people with type 2 diabetes.
The discovery could be vital not only for those with diabetes or prediabetes, but also for those who are trying to manage their weight.
Studies have indicated that people who eat diets low in saturated fat and high in fiber have lower risks for many chronic diseases, including diabetes, heart disease, and constipation.
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New research from the Finnish Diabetes Prevention Study disclosed that people who ate more fiber had more of an anti-inflammatory chemical in their blood called indolepropionic acid, which is produced by gut bacteria. Also, such people were not likely to suffer from type 2 diabetes.
The new study which was carried out last year, shows how fiber helps grow bacteria in the gut that produce chemical signals that help to regulate appetite and blood sugar.
Vanessa de Mello Laaksonen, PhD, an assistant professor in nutrigenomics at the University of Eastern Finland, who wasn’t involved in the research said;
“Overall, this study adds to what we know about how important the gut microbiota is when it comes to the development of some chronic diseases, like type 2 diabetes.”
Could High-Fiber Diets Destroy Diabetes?
Type 2 diabetes is the most common form and is drastically increasing.
A team of scientists in China surveyed 27 people with type 2 diabetes on a very high-fiber diet and followed them for 12 weeks, measuring changes to their blood sugar, and also to their gut bacteria.
They compared this group with 16 others who also had type 2 diabetes but consumed less fiber and who got standard advice on exercise and eating right for diabetes.
The high-fiber group was getting a huge 37 grams of fiber a day, while the group getting the average, healthy diet was eating about 16 grams of fiber a daily.
Both groups were also taking a medication called acarbose to help manage their blood sugar. Acarbose acts a bit like fiber because it prevents some carbohydrates from being digested in the gut for energy. All participants were weaned off any other medications to manage their blood sugar before the start of the research. If they used insulin, it was adjusted as needed throughout the study.
At end of the experiment, the group on the very high-fiber diet was healthier than the group getting standard care. They had better control of their blood sugar, and they’d lost weight a bit. About 90% of the high-fiber group achieved good control of their blood sugar, keeping their hemoglobin A1c under 7%, which is the target recommended by the American Diabetes Association — compared with just 50% of the group on a standard diabetes diet.
All that fiber, which came from a wide variety of food sources, fertilized the growth of 15 strains of bacteria that produce certain short-chain fatty acids. Those acids act as both a fuel source for cells and as messengers.
In the new study, these short-chain fatty acids signaled the gut to make more glucagon-like peptide-1 (GLP-1) and peptide YY (PYY).
GLP-1 is a hormone that tells the body to make more insulin, while PYY dials down appetite. The two are vital in controlling weight and blood sugar.
Some diabetes drugs also work by increasing GLP-1. The increase in short-chain fatty acids also made the gut walls ill-disposed to other kinds of bacteria that block GLP-1, thereby enhancing the effect.
“This is one benefit, one reason why high-fiber diets work,” says study researcher Liping Zhao, PhD, a professor of applied microbiology at both Rutgers University in New Brunswick, NJ, and Shanghai Jiao Tong University in Shanghai, China.
To ensure it was the change in gut bacteria that was the trigger for the results, the scientists then transferred the gut bacteria from their study participants to mice that were bred to be germ-free. Because they were bred not to have any of their own gut bacteria, scientists could later introduce bacteria and watch what happened as they began growing.
The mice that got the bacteria from the humans on the high-fiber diets had better fasting blood sugar levels than mice that got bacteria from people on the usual diabetes diet, even though they were eating the same chow.
The study was published in the journal Science.
The study authors say it would be difficult for the average person to copy their high-fiber diet. People in the high-fiber part of the study ate a specially prepared gruel made from white beans, oats, yams, yellow corn, red beans, peanuts, and lotus seeds, along with two whole grains that are unfamiliar to Westerners — green buckwheat and adlay, or Job’s tears. They also got more fiber in the form of powders that included bitter melon, kudzu starch, inulin, and resistant dextrin.
What’s important, researchers say, is the principle of all this: The good bacteria in our guts, the ones that keep us healthy, need a lot more fiber than we’re now giving them to thrive.
According to U.S. dietary guidelines, the Department of Agriculture endorses that healthy adults eat somewhere between 22 and 34 grams of fiber every day, Most of us only get about half that much.
Kids and adults are so short on fiber in the U.S. that the expert panel that put together the most recent version of the dietary guidelines singled out fiber as one of four “nutrients of public health concern.”
The study suggests that the bacteria that help us regulate our appetite and control our blood sugar get overwhelmed by other bacteria that suppress those all-important signals.
The researchers think high-fiber diets are possible with a little planning.
“We think that some 30-40 grams per day may not be unrealistic if you use whole-grain products, fruit and vegetables several times a day, instead of low-fiber bread, sugar-containing juices, and meat,” says Laaksonen.
Sources of fiber in their healthy Nordic Diet focuses on whole grains like rye, barley and oats, berries, and beans and peas.
The study also shows something else that’s important to understand about gut bacteria: They’re already there, and they change in response to our diets.
Most studies have shown that probiotic supplements, which assures millions of helpful bacteria to our guts, have few effects that usually don’t last long. This is because the bacteria that live inside us are there because of what we take in.
The best way to change them in a lasting way is to change their food source which is our diets.
“When you introduce a large amount of diverse fibers into the gut, it’s just like you threw some new nutrition into a pond. You disturb the system. Some members will take advantage of that to grow and increase their population levels. Some others may decline,” Zhao says.