Is leaky gut real?

“Leaky gut syndrome is a condition where undigested proteins like gluten, toxins and microbes can pass into the bloodstream,” cautions chiropractor Josh Axe on his website,

“Over time, if leaky gut is not healed, it can lead to food sensitivities, arthritis, inflammatory bowel disease, skin issues like eczema, hypothyroidism, adrenal fatigue, depression, anxiety, ADHD, nutrient malabsorption and autoimmune disease,” he goes on.

“Alternative medicine has embraced the concept of leaky gut syndrome, blaming it for nearly everything that can go wrong with a person,” says Alessio Fasano, director of the Center for Celiac Research and Treatment at Massachusetts General Hospital for Children.

In contrast, “modern medicine disregards leaky gut syndrome as voodoo medicine because of claims that it causes so many problems when there is no evidence,” he notes.

“In my opinion, both camps are wrong.”

The lining of your gut is a single layer of cells that sits between you and the contents of your intestines. Until recently, scientists thought that the cells were so tightly sealed together that nothing passed between them.

Then, “in the ’90s, researchers showed that there are structures—now called tight junctions—between neighboring cells,” explains Fasano. “They’re like doors, and most of the time we want them closed to keep the bad guys out.”

“There are billions of doors in the small intestine,” Fasano points out. “Depending on the percentage that are open and for how long they’re open, you can have an increase in gut permeability.”

Zonulin, a family of proteins that Fasano discovered in 2000, is the “key that unlocks the door,” he says.

That may explain why researchers report elevated blood levels of zonulin—and increased gut permeability—in many people with celiac disease, type 1 diabetes, Crohn’s disease, and some other autoimmune or inflammatory diseases.

Unfortunately, “there’s no reliable test for gut permeability,” says Fasano. Most researchers use several tests to measure it.

What’s more, “some people believe that just because you have an intestine that leaks, that’s a problem,” says Fasano. “But that’s not true.”

“It depends on what you find on the other side of the door. If you have a genetic predisposition and a belligerent immune system that doesn’t know how to manage invaders, you may develop disease.”

Fasano’s “holy grail”: figuring out who those people are early in life and preventing gut permeability in an effort to ward off autoimmune disease. But we’re nowhere near being able to do that yet.

Is there any evidence that supplements, probiotics, or Josh Axe’s Eat Dirt diet can heal a leaky gut?

“Of course not,” says Fasano. “How can you claim that these remedies can fix a problem if you don’t even know if someone has it?”

Bottom Line: Don’t waste your time on diets or pills that claim to fix leaky gut.

The information in this post first appeared in the June 2019 issue of Nutrition Action Healthletter.

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