You may have come across the term leaky gut — also known as increased intestinal permeability — and wondered what it is and if it’s real. The answer is not simple.

Digestion of the food we eat begins in our mouth, and continues in our stomach. Food is broken down still further in the 20-foot-long small intestine. Bacteria in our colon (the gut microbiome) complete the digestive process.

Nutrients enter our bloodstream in the small intestine, via hundreds of small, finger-like projections called villi, each of which contains small blood capillaries. The lining of the small intestine is only one cell thick. Nutrients enter the bloodstream primarily by passing through these cells, although some enter between the cells. The purpose of the small intestine’s lining is to let nutrients in but to keep the bad guys out — bacteria, incompletely-digested food, and toxins. Leaky gut refers to this process of the lining of the small intestine failing to keep the bad things out of our bloodstream.

In a healthy gut, this barrier works well, but in an unhealthy gut — present in conditions such as Crohn’s and celiac disease — some of the bad guys get into our bloodstream and cause inflammation, which contributes to many health problems. Harvard Health Publishing notes that some studies suggest that leaky gut may be linked to autoimmune diseases, such as lupus, type 1 diabetes, and multiple sclerosis. Other studies suggest it may be linked to chronic fatigue syndrome, fibromyalgia, arthritis, allergies, asthma, acne, obesity, and some forms of mental illness. However, in spite of several scientific studies over the past several years, definite proof of the link between leaky gut and these conditions is still lacking.

There may be some genetic predisposition for some people to develop leaky gut. And the Harvard publication notes that “there is emerging evidence that the standard American diet, which is low in fiber and high in sugar and saturated fats, may initiate this process,” as might heavy alcohol use. On his website nutritionfacts.org, Dr. Michael Greger cites studies that show a link between eating animal products and leaky gut, which would explain why people on lifelong plant-based diets have a much lower incidence of autoimmune and inflammatory diseases.

The treatment for leaky gut is to eat a diet that is rich in fiber, and in micronutrients including antioxidants; as well as a diet that is anti-inflammatory — the same diet that is the healthiest for us anyway.  What does such a diet look like? You guessed it:  A plant-based, unprocessed food diet with no salt, sugar or added oil.

Alessio Fasano, M.D. is director of the Center for Celiac Research and Treatment at Massachusetts General Hospital for Children in Boston, and is a respected expert in leaky gut. In 2000, he discovered Zonulin, a family of proteins that is the “key that unlocks the doors between the cells that line our small intestine.” A few years ago the evidence-based journal Nutrition Action, published by the Center for Science in the Public Interest, contained an article about Leaky Gut Syndrome. In it Dr. Fasano is quoted as saying that “alternative medicine has embraced the concept of leaky gut syndrome, blaming it for nearly everything that can go wrong with a person.” A lucrative business has evolved selling supplements and probiotics claiming to treat leaky gut (check the internet).

Dr. Fasano states that there is no evidence that supplements, probiotics, or chiropractor Josh Axe’s “Eat Dirt” diet can cure leaky gut. There is no reliable test that proves whether someone has or doesn’t have leaky gut. As Dr. Fasano points out: “How can you claim that these remedies can fix a problem if you don’t even know if someone has it?”

The bottom line at the end of the Nutrition Action article is: “Don’t waste your time on diets or pills that claim to fix leaky gut.”  Stay tuned over the next few years as researchers lean more about leaky gut.

Dr. Greg Feinsinger is a retired family physician who started the non-profit Center For Prevention and Treatment of Disease Through Nutrition. For questions or to schedule a free consultation about nutrition or heart attack prevention contact him at gfmd41@gmail.com or 970-379-5718.