The brain’s natural aging process can be slowed down with a very simple measure: eat more fiber.
Protect the brain with fiber
In the course of aging, chronic inflammatory processes occur in the brain. The so-called microglia are particularly affected. These are special immune cells in the brain. If inflammatory processes occur here, these cells form pro-inflammatory messenger substances that are known to impair cognitive and motor functions – which could therefore be an explanation for a deterioration in memory and the other typical signs of aging.
According to a study, however, the inevitable can be significantly delayed, namely – as mundane as it may sound – with the help of dietary fiber . The researchers at the University of Illinois explain the connections as follows:
Dietary fiber reduces inflammation in the brain
Dietary fiber encourages the beneficial gut bacteria in the gut. When these bacteria metabolize fiber from food, they form, among other things, short-chain fatty acids, e.g. Butyrate.
“Butyrate is such a particularly interesting substance because it has an anti-inflammatory effect on the microglia. It has also been shown to improve memory in studies, at least in mice,” explains Professor Rodney Johnson, author of the study, which was published in Frontiers in Immunology ( 1 ).
Inflammation in the brain is linked to Alzheimer’s
Despite the positive results of previous studies, the mechanism by which butyrate is so beneficial to the brain was not clear. Johnson’s study has now shown that butyrate – when taken as a pure substance in the form of a dietary supplement – prevents the inflamed microglia from producing inflammatory messenger substances. One of these harmful substances is interleukin-1, which appears to be closely related to Alzheimer’s in humans.
Does eating fiber produce enough butyrate?
In another experiment, the researchers wanted to find out whether simply consuming fiber would have the same effect as taking the isolated butyrate, i.e. whether consuming fiber alone can produce enough butyrate in the intestine to protect the brain from inflammation . Because butyrate is unfortunately out of the question as a dietary supplement for humans, as it has an extremely deterrent smell.
“We know that nutrition has a very large influence on the composition and functions of the intestinal flora. Those who eat high-fiber feed the beneficial bacteria, while those who eat high in fat and protein might feed a less healthy intestinal flora. So you can influence the intestinal flora with a targeted diet and in this way in turn influence or prevent a certain disease,” says Professor Jeff Woods, co-author of the study.
In concrete terms, the experiment looked like this: Different groups of young and older mice were fed either high or low fiber and then measured the butyrate level in the blood, the level of other short-chain fatty acids and the levels of inflammatory messengers in the intestine.
As we age we are particularly prone to unhealthy eating
The high-fiber diet increased butyrate levels, as well as levels of the other short-chain fatty acids, in all mice, young and old. The low-fiber diet, on the other hand, only caused inflammatory processes in the intestines of the older mice. Apparently, younger people can still compensate well for an unhealthy diet, which is no longer possible in old age.
Existing inflammation can be reversed again
However, if the older mice also received roughage, the existing inflammation – both in the intestine and in the microglia – was reduced dramatically, so that ultimately there was no longer any difference between the age groups. Johnson explains:
“A high-fiber diet can clearly control and regulate the inflammatory processes in the intestine.”
Although the study was conducted on mice, Johnson says the results can easily be extrapolated to humans. He summarizes: “What you eat matters! We know that older people eat 40 percent less fiber than officially recommended. However, not eating enough fiber can have extremely negative effects on areas of the body that have not previously been associated with fiber, such as the brain.
However, previous research had already shown that a high-fiber diet itself protects against lung diseases and also reduces the risk of death after a heart attack . And if pregnant women eat high-fiber foods, they can reduce their child’s risk of asthma with this dietary measure .
What foods contain fiber to protect the brain?
The recommendation for dietary fiber is: 30 grams per day! The study above focused specifically on soluble dietary fiber. It is true that most high-fiber foods contain both soluble and insoluble fiber. However, a particularly large amount of soluble dietary fiber can be found in fruits (pectin , especially in apples, blueberries, currants, gooseberries), in linseed and psyllium husk powder. The soluble fiber is characterized by the fact that it binds water and thus swells.
Inulin is also a soluble fiber that can be taken as a dietary supplement. Likewise, the beta-glucan in oats, oat bran and barley is part of the soluble fiber. Dried fruits such as Prunes are also a very good source of fiber. Always remember to drink plenty of water when eating high-fiber foods!