New research has revealed the mechanism by which fiber can delay brain aging.
Consuming foods rich in fiber such as oats, broccoli, nuts, beans, and whole-grain bread, might help delay brain aging by activating the production of a fatty acid that has anti-inflammatory properties.
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Rodney Johnson, professor and the head of the Department of Animal Sciences at the University of Illinois at Urbana-Champaign, is the corresponding author of the study, and Stephanie M. Matt is the first author of the paper.
How fiber helps to lower inflammation
According to the researchers, microglia, which is a major type of immune cell in the brain, appears to become hyperactive and inflamed as a person advances in age. This inflammation of the microglia is one of the main causes of memory and cognitive decline among seniors.
From previous research, a drug form of butyrate, which is a short-chain fatty acid that is produced in the colon when bacteria ferment fiber in the gut, can improve memory and ease inflammation in rodents.
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Though the exact mechanisms behind this discovery weren’t totally understood. Previous study had not also shown whether simply increasing the dietary content of fiber would accomplish the same results as the drug.
The researchers fed young and aging mice diets high and low in fiber in this recent research, then measured the blood levels of butyrate of the mice and their levels of pro-inflammatory substances in their intestines.
This study was published in the journal Frontiers in Immunology of late.
From the conclusion of Prof. Johnson;
“The high-fiber diet elevated butyrate and other short-chain fatty acids in the blood both for young and old mice. However, only the old mice showed intestinal inflammation on the low-fiber diet. It’s interesting that young adults didn’t have that inflammatory response on the same diet. It clearly climaxes the helplessness of being old.”
Consuming a high-fiber diet reduced the intestinal inflammation in aging mice so much that it was vague from that of young mice.
“Dietary fiber can really influence the inflammatory environment in the gut,” says Prof. Johnson. But is this equally applicable to the brain?
Why fiber is good for your brain
A genetic study of inflammatory markers conducted by same researchers discovered that a high-fiber diet eased inflammation in the brain’s microglia. The researchers suspect that this was achieved by lessening the production of a pro-inflammatory chemical known as interleukin-1β, which some studies have linked with Alzheimer’s.
Study co-author Jeff Woods, a professor in the Department of Kinesiology and Community Health at the University of Illinois at Urbana-Champaign, comments on the findings.
“We know that diet has a major influence on the composition and function of microbes in the gut and that diets high in fiber benefit good microbes,” he points out, “while diets high in fat and protein can have a negative influence on microbial composition and function.”
Altering gut microbes, explains Prof. Woods, “is one way in which [diet] affects disease.”
Prof. Johnson explains that the findings are significant to humans, adding that people are not likely to consume sodium butyrate directly, due to its unpleasant odor. However, a practical way to get elevated butyrate is to eat a diet high in soluble fiber.