It’s well known that eating nuts is healthy for the brain. But it is only just clear how powerful the link between healthy food and healthy brains is. The explanation for that is in your intestines.

As you get older, your memory and your ability to concentrate occasionally falter. That is perfectly normal and unfortunately not entirely avoidable. However, a healthy lifestyle allows you to keep your brain fit and healthy for longer. No smoking, enough sleep, regular exercise and staying mentally active all help to keep your brain in shape and even to keep Alzheimer’s disease at a distance.

But one of the most important things you can do for your brain is eat healthily. This is where, for example, the famous omega3 fats in nuts and salmon come into play. But the effect of nutrition on your brain is even stronger than that, according to recent research. This is because your diet determines the microbiome in your intestines, and that microbiome in turn has a big influence on your brain, and even on your mood and your behavior.

What is a healthy microbiome?

Our body is home to an impressive colony of hundreds of billions of bacteria, which together with other small organisms, such as viruses and fungi, form the microbiome. In total, each person would carry about one and a half kilos of that small grit, most of which is located in the intestines.
Your intestines contain a whole range of bacteria, both beneficial and rather harmful. How many bacteria there are of each species depends on the person. A healthy microbiome contains many different types of bacteria and of course relatively many beneficial and relatively little harmful ones.

A direct link between your intestines and your brain

What does that microbiome have to do with your brain? Many. Your intestines have a very extensive and complex nervous system. This is connected to both cognitive and emotional centers in your brain. Your endocrine system, which determines your hormonal functioning, and your immune system are also involved.

Among other things, through the vagus nerve, a large nerve pathway that runs from the intestine to the brain, signals from your digestive system reach your hypothalamus and thus affect your emotions and hormonal functioning. All those gut dwellers aren’t just sitting there doing nothing. All indications are that they themselves produce neurotransmitters – a kind of chemical messengers in your body – that affect your health.

Communication takes place in both directions. The activity in your brain also has an impact on what happens in your intestines. Something that people with stress-sensitive intestines are very aware of.

From obesity to Alzheimer’s to depression

A lot of research is still needed to find out exactly how your intestinal flora affects your brain and your health. But there’s no question that it is just doing that. From obesity, chronic fatigue, depression, allergies, autoimmune diseases to even psychiatric disorders, a disturbed microbiome is linked to all kinds of health problems.

The state of the bacteria in your intestines also has a clear influence on your brain. Researchers had subjects take probiotics – a mixture of bacteria – for four weeks. That not only changed the composition of their microbiome, but it also brought clear changes in the brain, especially in the parts related to emotions and pain processing.

Research has also shown a clear link between an unhealthy microbiome and the spread of Alzheimer’s disease. Please note, now, of course, a link does not mean with certainty that one is also the result of the other. However, there is no doubt that there is a correlation. Exactly how this works needs to be investigated further.

How do you keep your microbiome healthy?

The microbiome of your intestines is strongly influenced by your lifestyle. It adapts quickly according to your eating habits. In a few weeks, lifestyle changes are clearly visible in the composition of your gut bacteria. That is, of course, good news for those who want to do their best for a healthy microbiome.

What can you do yourself to keep your microbiome healthy?

• Eat healthily: Keeping your intestinal colony in top shape is done simply by eating healthily, especially fiber-rich vegetables. In particular, onions, asparagus, artichokes, garlic, bananas, and oats would be very healthy for the gut.
• Eat live bacteria: Foods containing live bacteria are also recommended. For example, you will find them in fermented milk products such as yogurt and sauerkraut. Kimchi, a type of Asian fermented cabbage, has also been shown to have beneficial effects on cognition and memory, research show.
• Probiotics: That brings us to the probiotic supplements, beneficial strains of bacteria that are deliberately intended to improve your intestinal flora. However, probiotics are not uncontroversial. Some say they won’t survive the stomach acid. Others say they have little effect. Still, there’s some evidence in their favor. For example, research has shown that daily consumption of probiotics can have a beneficial effect, especially on the symptoms of depression and anxiety disorders. Research in students before and during the exam period with a probiotic also found that probiotic users experienced fewer stress symptoms than the placebo group.
• If possible, avoid antibiotics: Antibiotics cause a massacre in your gut bacteria. Some strains of bacteria are more sensitive to them than others. Antibiotics therefore reduce the biodiversity in your intestines, so to speak. As a result, less beneficial strains of bacteria sometimes get the chance to start to proliferate. In some infections, antibiotics are inevitable, but do not take them if it is not necessary. With a virus like the flu, for example, they don’t do anything.
• Exercise: Regular exercise would also have a beneficial effect on the health of your microbiome. For example, the microbiome of elite athletes has proven to be healthier than that of ordinary mortals. Although the former usually also eat very healthy of course.

Bowel movements transplants

For now, it’s not for everyone, but scientists are achieving very hopeful results with bowel transplants. And yes, that happens exactly as it sounds. Your bowel movements contain a multitude of gut bacteria. By transplanting a little bowel movements from a healthy intestinal colony to an unhealthy intestine, you improve the intestinal flora there. When the bowel movements of healthy, slender mice were transferred to obese mice, the latter’s weight decreased and became healthier. Research also yields hopeful results in humans, but we are not yet at the time where bowel transplants are widely used.