The best foods to nourish your gut microbiome

Every time you eat, you are feeding trillions of bacteria, viruses and fungi that live in your gut. But are you feeding them the right food?

In the past, scientists knew very little about these communities of microbes that make up the gut microbiota, otherwise known as your gut microbiome. But a growing body of research suggests that these vast communities of microbes are the gateway to your health and wellness — and that one of the simplest and most powerful ways to shape and nurture them is through your diet.

Studies show that our gut microbes convert the food we eat into thousands of enzymes, hormones, vitamins and other metabolites that affect everything from your mental health and immune system to your chance of gaining weight and developing chronic disease.

Gut bacteria can even influence your mental state by producing mood-altering neurotransmitters such as dopamine, which regulates pleasure, learning and motivation, and serotonin, which plays a role in happiness, appetite and sexual desire. Some recent research suggests that the makeup of your gut microbiome may even play a role in how well you sleep.

But the wrong mix of microbes can produce chemicals that flood your bloodstream and build up plaque in your coronary arteries. The hormones they produce can affect your appetite, blood sugar, inflammation, and your risk of developing obesity and type 2 diabetes.

The foods you eat — along with your environment and lifestyle — seem to play a much bigger role in shaping your gut microbiome than genetics. In fact, genes have a surprisingly small effect. Studies show that even identical twins share only a third of the same gut microbes.

Your ‘good’ microbes feast on fiber and variety

In general, scientists have found that the more diverse your diet, the more diverse your gut microbiome. Studies show that high microbiome diversity correlates with good health and low diversity is associated with higher rates of weight gain and obesity, diabetes, rheumatoid arthritis and other chronic diseases.

Eating a wide variety of fiber-rich plants and nutritious foods appears to be particularly beneficial, said Tim Spector, a professor of genetic epidemiology at King’s College London and the founder of the British Gut Project, a crowdsourced effort to map thousands of individual people. to bring. microbiome.

Even if you already eat a lot of fruits and vegetables, Spector recommends eating more plant-based foods each week. A quick way to do this is to start using more herbs and spices. You can use a variety of leafy greens instead of one type of lettuce for your salads. Adding a variety of fruits to your breakfast, adding different vegetables to your stir-fries, and eating more nuts, seeds, beans, and grains is good for your microbiome.

These plant foods contain soluble fiber that passes through much of your GI tract largely unaffected until it reaches the colon. There, gut microbes feast on it, metabolizing and converting the fiber into beneficial compounds such as short-chain fatty acids, which can reduce inflammation and help regulate your appetite and blood sugar levels.

In one study, scientists followed more than 1,600 people for about a decade. They found that people with the highest levels of microbial diversity also consumed higher levels of fiber. And they gained even less weight during the 10-year study, which was published in the International Journal of Obesity.

Clusters of ‘bad’ microbes thrive on junk food

Another important measure of gut health is the ratio of beneficial microbes to potentially harmful microbes. In a study of 1,100 people in the United States and Britain, published last year in Nature Medicine, Spector and a team of scientists from Harvard, Stanford and other universities identified clusters of “good” gut microbes that protected people from cardiovascular disease. cardiovascular disease, obesity and diabetes. They also identified clusters of “bad” microbes that promoted inflammation, heart disease and poor metabolic health.

While it’s clear that eating plenty of fiber is good for your microbiome, research shows that eating the wrong foods can tip the balance in your gut in favor of disease-causing microbes.

The Nature study found that “bad” microbes were more common in people who ate a lot of highly processed foods that were low in fiber and high in additives such as sugar, salt and artificial ingredients. This includes soft drinks, white bread and pasta, cold cuts and packaged snacks such as cookies, candy bars and chips.

The findings were based on an ongoing project called the Zoe Predict Study, the largest personalized nutrition study in the world. It’s run by a health science company that Spector and his colleagues founded called Zoe, which allows consumers to have their microbiome analyzed for a fee.

Add more herbs, nuts, plants and fermented foods to your diet

Once you start increasing the variety of plant foods you eat each day, set a goal of trying to eat about 30 different plant foods per week, Spector says. That may sound like a lot, but you probably already eat a lot of these foods.

The sample menu shows how you can easily eat 30 different plant foods in just three meals over the course of the week.

  • Start your morning one day with a bowl of yogurt topped with sliced ​​bananas and strawberries, a dash of cinnamon powder, and a handful of mixed nuts (with almonds, pecans, cashews, hazelnuts, and peanuts). Meal count: 8 plant foods
  • On another day, eat a leafy salad with at least two mixed vegetables, tomatoes, carrots, broccoli, and peppers. Add Herbes de Provence, a seasoning that usually contains six herbs, to grilled chicken or fish. Meal count: 12 plant foods
  • Later in the week, eat chicken seasoned with pesto (it contains basil, pine nuts and garlic) and enjoy a bowl of brown rice with onions and kidney beans and a side of stir-fried vegetables with green and yellow squash, mushrooms and shallots. Meal Count: 10 Plant-Based Foods

Another way to nourish your gut flora is to eat fermented foods such as yogurt, kimchi, sauerkraut, kombucha, and kefir. The microbes in fermented foods, known as probiotics, produce vitamins, hormones and other nutrients. When you consume them, they can increase the diversity of your gut microbiome and boost your immune system, said Maria Marco, a professor of nutritional science and technology who studies microbes and gut health at the University of California, Davis.

In a study published last year in the journal Cell, Stanford researchers found that when they let people eat fermented foods every day for a period of 10 weeks, it increased their gut microbial diversity and lowered their inflammation levels.

“We’re increasingly developing a very rich understanding of why microbes are so good for us,” Marco said.

Do you have a question for Anahad about healthy eating? E-mail FoodLab@washpost.com and we can answer your question in a future column.

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