Studies show that our gut microbes transform the food we eat into thousands of enzymes, hormones, vitamins and other metabolites that influence everything from mental health and the immune system to the likelihood of gaining weight and developing chronic diseases .
Gut bacteria can even affect your mental state by producing mood-altering neurotransmitters like dopamine, which regulates pleasure, learning and motivation, and serotonin, which plays a role in happiness, appetite and sexual desire. Some recent studies suggest that the composition of your gut microbiome may even play a role in how you sleep.
But the wrong mix of microbes can produce chemicals that flood the bloodstream and form plaque in the coronary arteries. The hormones they produce can influence your appetite, blood sugar levels, inflammation, and your risk of developing obesity and type 2 diabetes.
The foods you eat, along with your environment and lifestyle behaviors, appear 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 one-third of the same gut microbes.
Your “good” microbes delight in fiber and variety
In general, scientists have found that the more diverse your diet, the more diverse your gut microbiome. Studies show that a high level of microbiome diversity correlates with good health, and that low diversity is linked to higher rates of weight gain and obesity, diabetes, rheumatoid arthritis and other chronic diseases.
Eating a wide variety of fiber-rich plants and nutrient-dense foods appears to be particularly beneficial, said Tim Spector, professor of genetic epidemiology at King’s College London and founder of the British Gut Project, a collaborative effort to map thousands of ‘individuals. microbiomes
Even if you already eat a lot of fruits and vegetables, Spector advises increasing the variety of plant foods you eat 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 several different vegetables to your stir-fry, and eating more nuts, seeds, beans, and grains is good for your microbiome.
These plant foods contain soluble fiber that passes through much of the gastrointestinal tract largely unaffected until it reaches the large intestine. There, gut microbes feast on it, metabolizing it and turning the fiber into beneficial compounds like short-chain fatty acids, which can reduce inflammation and help regulate appetite and blood sugar levels.
In one study, scientists followed more than 1,600 people for about a decade. They found that people who had the highest levels of microbial diversity also consumed higher levels of fiber. And they even gained less weight during the 10-year study, which was published in the International Journal of Obesity.
Groups of “bad” microbes thrive on junk food
Another important measure of gut health is a person’s ratio of beneficial 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 groups of “good” gut microbes that protected people against disease cardiovascular and obesity. and diabetes They also identified groups of “bad” microbes that promoted inflammation, heart disease and poor metabolic health.
While it’s clear that eating lots of fiber is good for your microbiome, research shows that eating the wrong foods can tip the scales in your gut in favor of disease-promoting microbes.
The Nature study found that “bad” microbes were more common in people who ate a lot of highly processed foods that are low in fiber and high in additives such as sugar, salt and artificial ingredients. This includes soft drinks, white bread and white pasta, processed meats and packaged snacks such as cookies, candy bars and chips.
The findings were based on an ongoing project called the Zoe Predict Study, the world’s largest personalized nutrition study. It’s run by a health sciences company that Spector and his colleagues created called Zoe, which allows consumers to have their microbiomes analyzed for a fee.
Add more spices, nuts, plants and fermented foods to your diet
Once you start increasing the variety of plant foods you eat each day, set a goal to try to eat around 30 different plant foods a week, says Spector. That may sound like a lot, but you’re probably already eating a lot of these foods.
The sample menu shows how in just three meals throughout the week you can easily eat 30 different plant foods.
- One day, start your morning with a bowl of plain yogurt topped with sliced bananas and strawberries, a sprinkle of cinnamon powder, and a handful of mixed nuts (which include almonds, pecans, cashews, hazelnuts, and peanuts). Meal count: 8 plant foods
- On another day, eat a leafy salad with at least two mixed greens, tomatoes, carrots, broccoli, and bell 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 (contains basil, pine nuts and garlic) and enjoy a bowl of brown rice with onions and beans and a side of stir-fried vegetables with green and yellow squash, mushrooms and shallots. Meal count: 10 plant foods
Another way to nourish your gut microbiota is by eating fermented foods like yogurt, kimchi, sauerkraut, kombucha, and kefir. 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 health, said Maria Marco, a professor of food 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 assigned people to eat fermented foods every day over a 10-week period, their gut microbial diversity increased and their levels of inflammation
“Every time we develop a very rich understanding of why microbes are so good for us,” Marco said.
Have a question for Anahad about healthy eating? e-mail [email protected] and we can answer your question in a future column.