22 Jun 2023 Article

What is a Microbiome? Are microbiome and microbiota the same? And what is it exactly? Can you influence your microbiome by eating certain foods? Or by taking probiotics? You will find the answers in this article.

What is it, a microbiome?

The definition of a microbiome in biology refers to microorganisms (microbes, i.e. bacteria, yeasts and viruses) and their genes, while the term microbiota refers only to the microbes themselves. So not to the genes. And that’s the difference. The terms are often used synonymously and interchangeably. Gut flora is yet another synonym. In this article I choose to use the term microbiome. And I’m going to talk about the microbiome of the gastrointestinal tract, mainly the colon. The main functions of the microbiome are protection against pathogens and the digestion of fiber.

It’s all about balance

Each person has a completely unique network of microbiome that is determined by one’s DNA. A person is first exposed to microorganisms as a baby: during childbirth in the birth canal and through breast milk. Exactly which microorganisms the child is exposed to depends on the type of microorganisms found in the mother. Later on, exposure to the environment and eating certain food can alter one’s microbiome. That can turn out good or bad. It can be beneficial to their health. Or it may actually indicate a greater risk of disease.

We humans have both beneficial and potentially harmful microbes in our bodies. For your microbiome to work well for you, there must be the right balance. The healthy types of microbes should dominate the pathogenic ones. Disturbance in this balance is caused by, among other things, infectious diseases, certain diets or long-term use of antibiotics. As a result, the body becomes more susceptible to disease.

Nowadays there is a lot of interest in the microbiome from science. Links have been found between the composition of the microbiome and conditions such as intestinal diseases and obesity. However, it is still unclear how these findings can be translated into practice. What is clear is that a fiber-rich, plant-based diet ensures a healthy microbiome. People who eat a largely or completely vegetarian diet are also generally healthier. And does that have to do with the microbiome? Most probably.

What is known: microbiota stimulate the immune system, break down potentially toxic food components and synthesize certain micronutrients, for example vitamin K.

Can diet affect a person’s microbiome?

In addition to family genes, environment and drug use, diet plays a major role in determining what types of microbes live in the colon. A fiber-rich diet in particular has an impact on the type and amount of microorganisms in the intestines.

Dietary fiber can only be broken down and fermented by enzymes from the microbes that live in the colon. Short chain fatty acids (SCFA) are released during fermentation. This lowers the acidity of the colon. This in turn determines what type of microbiota is present. These must be able to survive in such an acidic environment. Lower pH limits the growth of harmful bacteria such as Clostridium difficile.

Microbiome and prebiotics

Foods that support elevated SCFA levels include indigestible carbohydrates and fiber. These fibers are sometimes referred to as prebiotics. They feed our beneficial microbes. While there are supplements that contain prebiotic fiber, there are many healthy foods that naturally contain prebiotics. This includes all fruits, vegetables, beans, and whole grains such as wheat, oats, and barley. All good sources of prebiotic fiber. The highest amounts are found in garlic, onions, leek, asparagus, Jerusalem artichoke, and in bananas.

Be aware that a high intake of prebiotic foods, especially if introduced suddenly, can cause gas production (flatulence) and bloating. Individuals with sensitive guts (for example, those with irritable bowel syndrome) should introduce these foods in small amounts to assess their own tolerance first. With continued use, tolerance will improve, and so you will experience fewer unpleasant side effects such as gas production.

Microbiome and probiotics

Probiotic foods contain beneficial live bacteria that can further alter a person’s microbiome. Examples include fermented foods such as kefir, yogurt, pickled vegetables, tempeh, kombucha tea, and miso. However, it is not clear how much of the bacteria contained in these foods actually reach the large intestine.

There are many different types of probiotics available in supplement form. Most of those probiotics belong to the lactobacills or bifidobacteria. The bacteria must be alive and present in a product in sufficient quantities to have any effect at all. Many health claims that were originally on probiotic supplements are no longer on them. They are no longer allowed, because the effect of probiotics has not been scientifically proven. However, probiotics can disrupt the balance of the microbiome. It is therefore not recommended to take probiotics without the advice of your doctor or another specialist.

The bottom-line

A healthy microbiome ensures better health. In addition to hereditary factors and medication, the exact composition of the microbiome is also determined by what we eat. Scientists are still cautious about giving concrete nutritional advice. They do see a positive connection between a plant-based diet and a favorable microbiome. Fiber-rich foods (vegetables, fruits, nuts, whole grains) are the basis for a healthy microbiome.