Dietary Fiber Protects the Brain in Old Age
The natural aging process of the brain can be slowed down by taking a very simple measure — eating more fiber.
Protect the brain with fiber
In the course of aging, chronic inflammatory processes develop 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 inflammatory messenger substances that are known to impair cognitive and motor functions — which could therefore be an explanation for a deteriorating memory capacity and the other typical signs of aging.
According to a study, however, the inevitable can be postponed significantly, namely — as mundane as it may sound — with the help of fiber. The researchers at the University of Illinois explain the relationships as follows:
Dietary fiber inhibits inflammation in the brain
Dietary fiber promotes the beneficial intestinal bacteria in the intestines. When these bacteria now metabolize fiber from food, they form short-chain fatty acids, e.g. B. butyrate.
“Butyrate is such a particularly interesting substance because it has an anti-inflammatory effect on the microglia. He has also been able to improve memory in studies, at least in mice,” explains Professor Rodney Johnson, author of the study, which was published in Frontiers in Immunology.
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 has not been clear. In Johnson’s study it has now been 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 disease in humans.
Does the consumption of dietary 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 enough butyrate can be produced in the intestine to protect the brain from inflammation through the consumption of fiber alone. Because butyrate is unfortunately out of the question as a dietary supplement for humans because it has an extremely off-putting smell.
“We know that diet has a major influence on the composition and functions of the intestinal flora. Those who eat high in fiber feed the beneficial bacteria, while those who eat high in fat and protein ensure the development of a rather unhealthy intestinal flora. With a specific diet, you can influence the intestinal flora and in turn influence or prevent a certain disease,” says Professor Jeff Woods, co-author of the study.
Specifically, the experiment now looked like this: Different groups of young and older mice were fed either high or low in fiber and then measured the butyrate level in the blood, the levels of other short-chain fatty acids and the levels of inflammatory messenger substances in the intestine.
In old age one is particularly prone to an unhealthy diet
The high-fiber diet increased butyrate levels and the 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 in older mice. Younger people can apparently still compensate for an unhealthy diet, which is no longer possible in old age.
Existing inflammations can be reversed
But if the older mice were also given dietary fiber, then the existing inflammation — both in the intestines and in the microglia — could be dramatically reduced, so that ultimately no difference could be seen between the age groups. Johnson explains:
“A diet rich in fiber can clearly control and regulate the inflammatory processes in the intestine.”
Although the study was done on mice, the results can be easily transferred to humans, according to Johnson. He sums it up: “What you eat is crucial! We know that older people eat 40 percent less fiber than is officially recommended. However, if you do not eat enough fiber, it can have extremely negative consequences, specifically on areas of the body that were previously not associated with fiber, such as the brain. “After all, when you think of fiber, you think of the intestines in particular.
In previous studies, however, it had already been 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 use this nutritional measure to reduce their child’s risk of asthma.
Which foods contain fiber to protect the brain?
The recommendation for fiber is 30 grams a day. The above study focused in particular on soluble fiber. Most high-fiber foods contain both soluble and insoluble fiber. However, a particularly large amount of soluble fiber is found in fruits (pectin, especially in apples, blueberries, currants, gooseberries), in flax seeds and psyllium husk powder. The soluble fiber is characterized by the fact that it binds water and thus swells.
Also Inulin is a soluble fiber, which can be taken as a dietary supplement. The beta-glucan in oats, oat bran and barley is also a soluble fiber. Dried fruits such as B. Prunes are also a very good source of fiber. Always remember to drink plenty of water with foods that are high in fiber!
