What is Gut Health?
It’s hardly news that the gastrointestinal tract is important to human health: It transports food from the mouth to the stomach, converts it into absorbable nutrients and stored energy, and shuttles waste back out of the body. If you don’t properly nourish yourself, you don’t live. It’s that simple.
But in recent years, scientists have discovered that the GI system has an even bigger, more complex job than previously appreciated. It’s been linked to numerous aspects of health that have seemingly nothing to do with digestion, from immunity to emotional stress to chronic illnesses, including cancer and Type 2 diabetes.
“We now know that the GI tract is full of trillions of bacteria that not only help us process food but that also help our bodies maintain homeostasis and overall well-being,” says Dr. Tara Menon, a gastroenterologist at the Ohio State University Wexner Medical Center. The key, experts say, may lie in the microbiome—the makeup of bacteria and other microorganisms in the stomach and intestines, or, informally, the gut.
Research on the microbiome is still in its infancy. But studies have already found that certain environments, foods and behaviors can influence gut health for better or worse. Here’s why that matters and what you can do to improve yours.
Everyone’s microbiome is unique, but there are a few generalities about what’s healthy and what’s not. “In healthy people, there is a diverse array of organisms,” says Dr. Gail Hecht, chair of the American Gastroenterological Association Center for Gut Microbiome Research & Education. (Most of those organisms are bacteria, but there are viruses, fungi and other microbes as well.) “In an unhealthy individual, there’s much less diversity, and there seems to be an increase of bacteria we associate with disease.”
Hecht stresses the word associate because scientists don’t know for sure which comes first—whether bacteria influence disease risk or whether existing disease influences gut bacteria. Most likely, she says, both are true. “We’re still lacking specific proof of how this connection works, but we know it’s there.”
Some bacteria fight inflammation, while others promote it. When the gut works as it should, these two types keep each other in check. But when that delicate balance gets skewed, inflammatory bacteria can take over—and they can produce metabolites that pass through the lining of the gut and into the bloodstream, spreading the inflammation to other parts of the body.
Specific types of bacteria in the gut can lead to other conditions as well. Studies in both animals and humans have linked some bacteria to lower immune function; others to greater risk of asthma and allergies; and still others to chronic illnesses like diabetes, heart disease, multiple sclerosis and some cancers.
Gut health has even been linked to anxiety and depression, and to neurological conditions like schizophrenia and dementia. The makeup of gut bacteria also varies between lean and overweight people, suggesting that it may play a role in causing obesity in the first place.