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Why the Amino Acid L-Glutamine Is So Important for Gut Health and Repairing Your Gut Lining (and the Foods That Have Plenty of It)

When it comes to gut health, keeping the intestinal epithelium—aka the gut lining—strong is a top priority. That’s because the cells in the intestinal epithelium have multiple, important jobs: They help digest food, absorb nutrients, and prevent bacteria and other toxins from seeping out from the intestines into the rest of the body (where they can wreak havoc in the form of infection and inflammation).

“Epithelial cells act as gates, almost like TSA agents: They don’t allow everything to come through,” says gastroenterologist Ali Rezaie, MD, MSc, Medical Director of the Gastrointestinal Motility Program at Cedars-Sinai, Los Angeles and co-author of The Microbiome Connection: Your Guide to IBS, SIBO, and Low-Fermentation Eating. “But if the epithelial cells are damaged, which we call hyperpermeability or ‘leaky gut,’ then bacteria can come inside the body and produce a microinflammation state.”

Ah yes, the infamous “leaky gut.” That’s where the amino acid glutamine (also referred to as l-glutamine) comes into play.

The most abundant amino acid in the human body, glutamine is a “building block” for proteins. It is produced naturally by the body (mainly in the muscles) and can also be found in many foods. Blood carries glutamine to tissues throughout the body, including the gut, where it promotes the regeneration of the epithelial cells that serve as a barrier between the intestines and abdominal cavity. According to Dr. Rezaie, the epithelial cells in the gut are completely replaced every five to seven days. “This fast rate of reproduction of these cells is dependent on glutamine,” he says.

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Generally, healthy individuals get all the l-glutamine they require from their body’s natural production and diet, says Dr. Rezaie. However, people who suffer from digestive disorders like celiac disease or Crohn’s disease may need more l-glutamine to keep their intestinal lining in optimal shape compared to those without these conditions. Additionally, if you do happen to be suffering from a leaky gut, you may need to up your l-glutamine intake in order to restore the intestinal epithelium. “Whenever there is inflammation, now all of a sudden you need a lot of energy to fight that and the cell turnover increases,” Dr. Rezaie says.

Foods with glutamine

There’s a good chance you already consume foods rich in glutamine on a regular basis. According to Dr. Rezaie, many elements of the Mediterranean diet—a largely plant-based diet that also includes whole grains, seafood, eggs, and lean poultry—are rich in glutamine, including fish, chicken, and eggs. Folks on strictly vegan or vegetarian diets can get their glutamine from the aforementioned whole grains, as well as cruciferous vegetables like cabbage and broccoli. However, for individuals for whom cruciferous vegetables cause bloating or distention, Dr. Rezaie recommends two other potent sources of glutamine: carrots and beets.

You can also find glutamine supplements on the market, but according to Dr. Rezaie, supplementation is only recommended in rare situations: For instance, a doctor may recommend that individuals who frequently engage in very heavy workouts (glutamine may aid in to muscle recovery) or those recovering from an infectious gastrointestinal condition consider this supplement. (One study suggested that glutamine supplements helped normalize the permeability of the gut lining in patients suffering from postinfectious irritable bowel syndrome.) “But on a day to day basis, you generally you don’t need supplementation on this, unless for whatever reason you are on some sort of very restricted diet,” says Dr. Rezaie. Be sure to consult with a medical provider before starting on any new supplements.

For more expert-backed intel on optimal gut health, check out this video: