4 ways your gut affects your health

When you think of your gut, you probably think of the major organs that reside there, like your stomach and large and small intestine. But your gut also houses some 500 trillion cells and other organisms. The microbial mix you end up with affects your physiology, metabolism, immune function and nutrition. Researchers have come to view this aggregation of gut bacteria as a hidden metabolic “organ,” given its wide-ranging impact—some good, some not-so-good—on our health and well being. As scientists continue to probe further, certain changes in stomach bacteria have been linked to conditions like multiple sclerosis (MS), Parkinson’s disease and even obesity.

Your GI tract is in good working order when nutrients and water are properly absorbed and pushed through the digestive system; you have normal, regular bowel movements; there’s an absence of conditions such as irritable bowel syndrome (IBS) or colorectal cancer; and gut bacteria is in balance with normal activity in your gut immune system cells. While diseases that directly affect organs in the GI tract aren’t surprising, research is suggesting that some seemingly unrelated illnesses get their start there.

A connection between gut bacteria and immunological disorders like multiple sclerosis has long been suspected. But one 2016 study, conducted by researchers at Brigham and Women’s Hospital, uncovered evidence of a link between gut bacteria and MS. The investigators discovered different patterns of gut microorganisms in untreated MS patients as compared to healthy people and MS patients undergoing treatment. The gut microbiomes were normalized for MS patients receiving treatment. This discovery could spur the development of new therapies to treat the disease.

Researchers have long suspected a link between Parkinson’s disease (PD) and the GI tract. One symptom of Parkinson’s is constipation, and it can precede the decline of motor function by years. New research suggests the connection between PD and the gut is a two-way street. Not only does PD affect gut function, the presence of higher levels of a specific family of bacteria in the gut, Enterobacteriaceae, may be associated with more severe Parkinson’s symptoms. More research is needed to determine the definitive connection between the gut and PD, but researchers believe detection of bacteria may help with prognosis, treatment and early diagnosis.

There is a link between conditions like Crohn’s disease and ulcerative colitis—two chronic inflammatory bowel diseases—and colorectal cancer. Bacteria associated with both Crohn’s and colitis cause inflammation in the GI tract; it’s suspected that that, in turn, may increase an individual’s risk of colorectal cancer. The right combination of bacteria in the gut make for a healthy digestive system—the wrong mix can cause inflammation. Finding the appropriate balance of gut bacteria may lead to better treatments for chronic inflammatory bowel disease and a reduced risk of colorectal cancer.

While your diet and activity levels contribute to weight gain and management, the gut microbiota—bacterium living in the gut—are likely involved as well. Studies suggest certain bacteria present in the gut of obese individuals may be responsible for increased energy harvest—capturing and storing nutrients and fat from food. Investigators speculate that there may be other links between the gut and obesity, including appetite, fat storage and inflammation, but more research is needed.