Roni Caryn Rabin in The New York Times:
If you’re making resolutions for a healthier new year, consider a gut makeover. Refashioning the community of bacteria and other microbes living in your intestinal tract, collectively known as the gut microbiome, could be a good long-term investment in your health. Trillions of microbial cells inhabit the human body, outnumbering human cells by 10 to one according to some estimates, and growing evidence suggests that the rich array of intestinal microbiota helps us process nutrients in the foods we eat, bolsters the immune system and does all sorts of odd jobs that promote sound health. A diminished microbial ecosystem, on the other hand, is believed to have consequences that extend far beyond the intestinal tract, affecting everything from allergies and inflammation, metabolic diseases like diabetes and obesity, even mental health conditions like depression and anxiety.
Much of the composition of the microbiome is established early in life, shaped by forces like your genetics and whether you were breast-fed or bottle-fed. Microbial diversity may be further undermined by the typical high-calorie American diet, rich in sugar, meats and processed foods. But a new study in mice and people adds to evidence that suggests you can take steps to enrich your gut microbiota. Changing your diet to one containing a variety of plant-based foods, the new research suggests, may be crucial to achieving a healthier microbiome. Altering your microbiome, however, may not be easy, and nobody knows how long it might take. That’s because the ecosystem already established in your gut determines how it absorbs and processes nutrients. So if the microbial community in your gut has been shaped by a daily diet of cheeseburgers and pepperoni pizza, for example, it won’t respond as quickly to a healthy diet as a gut shaped by vegetables and fruits that has more varied microbiota to begin with.