Why fiber is also good for your brain

Sudden diarrhea for an exciting presentation or constipation due to chronic stress. These are examples of communication between the brain and intestines, and vice versa. The intestines are also called the ‘second brain’; they contain just as many neurons (nerve cells) as the brain. These neurons communicate with the brain in different ways, for example via a long nerve – the vagus nerve in the spine. But there is also a communication route via the immune system. No less than seventy percent of that immune system is located in the intestines and helps keep us healthy. A leading role is played by intestinal bacteria, which produce substances that communicate with the brain via the blood. With our diet we can keep those important intestinal bacteria as healthy as possible, so that diseases are less likely to develop and you feel better.

These substances are said to be beneficial for intestinal bacteria. Only use under the guidance of a dietician or doctor.
Prebiotics: food for good microorganisms that live on or in the body. Found in bananas, garlic, onions, among others. Are also added to products.
Probiotics: live bacteria that can help after antibiotics, poor diet or travel. The European Food Safety Authority has only approved one health claim. However, a beneficial effect has been shown for certain depressive complaints. If you have (continually) changing stools, go to the doctor and take the checkjepoep test from the Maag Lever Intestine Foundation (mlds.nl).

Intestinal bacteria determine your health

The word bacteria may sound like ‘go, wash your hands’, but in addition to bad bacteria, there are many good and important bacteria. That collection of bacteria and fungi that live in the (mainly large) intestine is called intestinal flora, microbiota or microbiome. It is almost impossible to imagine how many of those tiny, invisible intestinal inhabitants we have: a hundred times a million times a million. Ten times as many cells live in the intestines as in our entire body. It becomes even more impressive when you consider that every disease or condition is related to the health of that intestinal flora. Psychiatrist Prof. Dr. Iris Sommer wrote the book about this The bacteria and the brain. “These intestinal bacteria determine our health, whether we are thin or fat and how many hormones are sent into the body.” And are therefore also decisive for diseases, including brain diseases that we mainly develop later in life.

The cleaner, the unhealthier

But let’s start young. In her book, Sommer states that breast milk through breastfeeding already lays the foundation for good intestinal bacteria and for a healthy weight later. Even at that young age, the environment is also important. “The following does not apply: the cleaner the better. Toddlers put all kinds of things in their mouths. This results in an enrichment of the intestinal flora. So a ‘dirty’ environment with a dog, house dust or livestock is beneficial and has health benefits. So don’t forget the second R with the trio of Peace, Cleanliness and Regularity.” Now, on average, adults do not put toys in their mouths and do not cuddle chickens or cows. So little intestinal flora enrichment. In addition, they often use medications. Iris Sommer: “They have a great effect on intestinal bacteria. Antibiotics are notorious, a battle for healthy intestinal flora.” Because an antibiotic not only destroys harmful inflammatory bacteria, but also many innocent good ones. To keep things healthy or to get them healthy, the flora has an important requirement: good, varied nutrition with the magic ingredient: fiber. “And especially fibers that the small intestine cannot break down, then they arrive undamaged in the next stage: the large intestine. Fiber is mainly found in vegetables and fruit, but I like to eat them whole – so preferably not in smoothies or pressed juice. Also rich in fiber are whole wheat bread with whole grains, citrus fruit and rice with skin, apples and potatoes with skin and the firm pieces of the broccoli stem.” So stop peeling and scraping.

How much fiber does…

No refined foods

Prof. Dr. Koen Venema, until recently an intestinal microbiologist at the University of Maastricht, has been studying the health of intestinal flora for 25 years and advises on it from his company Beneficial Microbes Consultancy. He also emphasizes the importance of fiber. “And we should also avoid refined foods that have been processed in factories. Everyone understands that junk food, chips and cookies are part of it. But white bread, white rice and white pasta are also refined, as they contain little fiber. And just stick to the Wheel of Five for variation and quantities.” Venema explains why fiber from unrefined food is so important for health. “Intestinal bacteria eat those fibers. They use this to produce valuable substances that strengthen the intestinal wall. Pathogens and hazardous substances cannot pass through it as easily. If the intestinal flora does not get fiber, they will eat other things, which will deteriorate the intestinal wall. The result: diseases.” But intestinal flora are not necessarily the instigator of a disease, according to Koen Venema. “They can influence the severity or course. In other words: optimizing intestinal bacteria is beneficial in the case of diseases.” Because of gut-brain communication, this even applies to brain diseases such as Parkinson’s, Alzheimer’s disease, schizophrenia and bipolar disorder. And the effect also seems positive for chronic fatigue. But it is not yet possible to say by what percentage the (risk of) disease decreases as a result of certain foods. Moreover, every brain disease has its own mechanism.

Less fungi, more bacteria

Jacqueline (64) noticed that a change in diet can indeed influence brain disease. “I’ve had migraines since I was thirteen. When I went on a cheese-free diet, my attacks decreased from twice a week to twice a year! Most likely due to a mold found in cheese. According to the neurologist, that couldn’t be the reason, so my mother secretly added cheese to my food to check. I promptly had an attack the next day. Also, when I accidentally ate fruit with a moldy piece, I got a migraine.” Jacqueline had the same experience with inhaling mold. “Twice a year I walked in the dunes, where there turned out to be a certain species of fungus. After such a walk I invariably had an attack. So yes, I am sensitive to mold, so I avoid it now.” Psychiatrist Iris Sommer also mentions the effect of fungi in her book. “Ten-year-olds developed ADHD more often if there were more and different molds in the house dust. So the more bacteria and the fewer fungi there are in house dust, the more diverse the child’s intestinal flora and the more protection against ADHD.”

The amount of fiber per product can be found at:
• The Calorie Checker, voedingcentrum.nl/caloriechecker
• The app Do I choose healthy? via the app store or voedingcentrum.nl

Fibers make the difference

One of the studies that showed the influence of intestinal flora on the brain was a study with two groups of mice: aggressive and timid. Koen Venema: “A ‘poo transplant’ was performed on both. They were given each other’s poop, so it was full of intestinal bacteria. As it turned out, the behavior of the aggressive mice became significantly milder, and the timid mice became more aggressive. That is really concrete evidence that those intestinal bacteria also have an influence mentally. Poop transplants are also sometimes performed on humans. Namely in the case of an infection with the harmful bacterium Clostridium difficile. About 90 to 95% then heal.” Doctors are increasingly advising their patients to eat more fiber. For example, Eva (52)’s psychiatrist recommended a high-fiber diet for her depression. “I thought that was very strange. There was nothing wrong with my stomach, but in my head. I wasn’t very hungry anyway, so I wasn’t keen on whole grain options. Moreover, I was taking medication that had made me fatter, so I didn’t want to eat more, which I actually had to do.” She therefore refused. But the psychiatrist talked about the influence of a healthy microbiome on the brain. He suggested we try it for a month. If it didn’t do anything, she could stop. “Then I just did it. I ate ‘white’ products such as bread and pasta in the whole wheat variety. White rice became brown rice. I also dutifully ate three pieces of fruit a day and varied more in terms of vegetables.” The change was striking, Eva thought. Not that she suddenly danced through life jubilantly, but her mood became more stable and her bowel movements also became more regular. “After that agreed month I continued with it. Six months later I even had the courage to stop taking my antidepressant. I really want to recommend everyone to eat healthy. Because I couldn’t have imagined that it would have such an impact on my brain!”

Illustrations: Stocksy. In collaboration with intestinal microbiologist Prof. Dr. Koen Venema (Beneficial Microbes Consultancy), Suzan Tuinier (Nutrimedia)