Immune cells in the brain, also known as microglia, will become inflamed chronically as you age. Inflamed immune cells may produce chemicals that can cause damage to your motor and cognitive function. Thus, your memory and other brain functions may decline over time.
A new study from University of Illinois reports that dietary fiber may delay the decline in memory and other brain functions.
Dietary fiber can boost the growth of good bacteria in the gut. When good bacteria in the gut digest fiber, they will produce short-chain-fatty-acids (SCFAs), including butyrate. Butyrate has been proved to have anti-inflammatory properties on immune cells in the brain. Thus, high-fiber-diet may help delay the decline in memory and other brain functions.
The study is led by Rodney Johnson who is a professor and head of the Department of Animal Sciences at U of I, and a corresponding author on the Frontiers in Immunology study.
He said: “Butyrate is of interest because it has been shown to have anti-inflammatory properties on microglia and improve memory in mice when administered pharmacologically.”
“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, while diets high in fat and protein can have a negative influence on microbial composition and function. Diet, through altering gut microbes, is one way in which it affects disease,” said Jeff Woods, professor in the Department of Kinesiology and Community Health at U of I, and co-author of this study.
Johnson continued: “The high-fiber diet elevated butyrate and other SCFAs in the blood both for young and old mice. But 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 highlights the vulnerability of being old.”
This study is conducted on mice, and the researchers examined about 50 unique genes in microglia. They found that high-fiber diet reduced the inflammatory profile in aged animals.
However, this study only tested the impact on inflammation. And more tests need to be done to examine the impact of high-fiber diet on cognition, motor function and other brain functions.