Another recent study confirmed that what you eat determines the microbes living in your gut (small intestines). This is the gut microbiome or microbiota (the community of bacteria, fungi, viruses). The microbes living in a person's gut can be determined by analyzing a sample of a person's poop.
The researchers found that persons eating more fruits, vegetables, and foods high in fiber (e.g., whole grains, fruits, vegetables, nuts, seeds) have gut microbes associated with health. They also have more diversity of species in the gut (this is a sign of health). But eat a diet rich in highly processed foods and low in fiber, and you'll have microbes associated with health problems (e.g., heart disease, cancer, diabetes).
The researchers point out that following the recommendations of the Dietary Guidelines for Americans (DGA) supports a healthy gut microbiome. Especially important for a healthy gut microbiome were vegetables, whole grains, legumes, and dairy. Yes, dairy foods have oodles of microbes (your cheese is alive!), whole fat dairy is beneficial, but skim milk or 0% is not. Eating a variety of high fiber foods is important because then you'll be eating a variety of fibers.
Bottom line: you are what you eat.
Excerpts from Medical Xpress: How diet quality affects the gut microbiota to promote health
We know that eating a healthy diet affects body weight, cholesterol levels, and heart health. A new study from the University of Illinois focuses on another component: the role of diet in supporting a healthy gastrointestinal microbiota. The researchers conclude that following the Dietary Guidelines for Americans (DGA) promotes a gut microbiota composition that may support overall health.
"Currently, there is no definition of a 'healthy' microbiome. Understanding how diet may influence the structure of the gut microbiota is important so we can make recommendations on dietary approaches," says Alexis Baldeon, doctoral student in the Division of Nutritional Sciences (DNS), part of College of Agricultural, Consumer and Environmental Sciences at U of I. Baldeon is lead author of the paper, published in The Journal of Nutrition.
The microbiota consists of trillions of microorganisms that live in the gastrointestinal tract. They contribute to many physiological processes, and a diverse gut microbiota may promote resilience to disruptions that could contribute to disease.
The researchers analyzed data from the American Gut Project, a large, crowdsourced database that includes fecal samples from thousands of individuals across the U.S. Their study focused on data from a subset of 432 healthy individuals divided into three groups according to how closely they followed the Healthy Eating Index (HEI), which is based on the DGA.
The group with the highest total HEI score, indicating the strongest compliance with the DGA, had the highest gut microbiota diversity, as well as a larger presence of bacteria that contribute beneficial functions like fiber fermentation, Baldeon says.
"The gut microbiota is really good at breaking down fiber, which is important because humans cannot digest fiber. Study participants with a higher diet quality had a greater abundance of bacteria involved in fiber metabolism," he notes.
Holscher and Baldeon note their study supports the current DGA recommendations for a diet rich in fruits, vegetables and fiber. Following those guidelines, outlined in MyPlate, is still the best strategy for your overall health, including nourishing your gut microbes.