We hear everywhere that our microbiome is important to our health, and that we should try to improve it. This sounds so complicated, but it’s not. It turns out that improving our microbiome can be done simply by making some changes to the foods we usually eat.

The human microbiome or microbiota are the trillions of microbes (bacteria, fungi, viruses) living in communities within and on a person – in the gut (intestines), mouth, sinuses, and everywhere else in the body. However, when people talk about the microbiome, they are usually referring to the gut microbiome.

Every person’s gut is packed with microbes, from 500 to more than 1000 species of bacteria! The gut microbiome plays key roles in our health, including digestion and our immune system. The presence of some species of bacteria in the gut is linked with chronic inflammation and some diseases (even cancer), while the presence of other bacterial species is associated with health and lower levels of chronic inflammation.

How does a person improve the gut microbiome? 

The numbers and types of bacteria living in the gut can be changed and improved. This can occur very quickly if a person makes changes in the foods that are regularly eaten.

This is because a person’s diet has a large effect on the types of bacteria that live in the gut. The foods a person eats feeds gut bacteria – so you want to feed and nurture beneficial bacteria that are associated with health, and not bacteria linked with inflammation and diseases.

Unfortunately, our modern Western lifestyle and diet (lots of highly processed foods, meat, refined grains, sugary drinks, and little dietary fiber) increases gut bacteria linked to chronic inflammation and diseases (e.g., diabetes, heart disease).

On the other hand, eating more fermented foods, unprocessed whole foods, especially plant-based foods, will increase the diversity and numbers of good species in the gut and improve health.

You can quickly improve your gut microbial community with the following steps.

Simple Steps to Improve and Nurture Your Gut Microbes:

- Eat a wide variety of foods, especially whole foods that are unprocessed or as minimally processed as possible. 

- Eat a diet rich in plant-based foods: fruits, vegetables, whole grains, seeds, nuts, and legumes (beans). Eat a variety of these foods, perhaps along the lines of a Mediterranean diet.

- Eat more fruits and vegetables, especially raw fruits and vegetables. Dietary guidelines are to eat at least 5 servings a day of fruits and vegetables (1/2 cup is 1 serving).

When you eat foods that naturally contain a lot of microbes (raw produce, cheeses, dairy, fish, fermented foods, etc.), you ingest the microbes. Each food type has different microbial communities. An apple can contain 100 million bacteria!

- Eat more fiber. Try to eat a variety of fiber foods in order to feed the variety of bacteria species in the gut. Good fiber foods are fruits, vegetables, whole grains, legumes (beans), nuts, and seeds. (Note: meat, dairy products, and seafood do not contain dietary fiber.)

Research suggests that over 25 grams of fiber daily for adults is best. It is best to get fiber from foods, and not from supplements.

- Eat as many organic foods as possible. Some research suggests that organic foods (especially produce) may contain more beneficial microbes. Also, some pesticide residues in non-organic foods may harm gut bacteria. 

Even if you can't or won't eat organic foods, it is better for our health to eat non-organic fruits, vegetables, legumes, seeds, nuts, and whole grains than to not eat them.

- Eat some fermented foods. Recent research shows that having some fermented foods each day is a quick way to increase gut microbial diversity (good!) and lower chronic inflammation.

Examples of fermented foods: yogurt, kimchi, sauerkraut, fermented vegetables, traditional pickles, natto, kefir, buttermilk, and many cheeses.

- Improvements to your gut microbiome can occur within a few weeks after making dietary changes. But to maintain the microbial changes you must continue with the new dietary pattern.

- Try to avoid or eat less of mass-produced highly processed foods, fast-foods, and foods containing emulsifiers  (linked to microbial disruption and gut inflammation), artificial ingredients, and high-fructose corn syrup. These promote bacteria linked to chronic inflammation and diseases.

Read all ingredient lists on labels, and try to avoid products with ingredients that you would not normally have in your kitchen.

- Get regular exercise or physical activity. Exercise and physical activity increase the numbers and types of good bacteria that live in the gut. Aim for at least 150 minutes (2 1/2 hours) per week of moderate intensity exercise. Brisk walking counts as exercise!

- Avoid unnecessary antibiotics. Antibiotics kill off both harmful and beneficial bacteria, so want to only use antibiotics when necessary.

- Daily probiotic supplements are not needed for gut health. The few bacterial species available for sale are not those that are most associated with good health (e.g., Faecalibacterium prausnitzii). Focus instead on eating a diet rich in fruits, vegetables, whole grains, seeds, nuts, and legumes.

Bottom Line:

The gut microbial community is important for our health. Improving your diet and getting some exercise is key to the health of your gut microbiome. You are what you eat!

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Food For Thought:

The National Institutes of Health says that currently more than 50% of the daily calories of the American diet is from ultra-processed foods. These convenience foods (e.g., fast foods, packaged meals, and desserts) do not feed beneficial gut microbes, but instead feed microbes linked to chronic inflammation and diseases.