L-Glutamine

Like all other amino acids, glutamine is the building block of many proteins in the body. What makes glutamine special, however, is that it is the most abundant amino acid in the body and is considered the main energy source for cells that make up the gut lining, known as enterocytes. While this amino acid can typically be synthesised in the body in adequate amounts, it may become necessary to obtain glutamine from the diet in periods of illness or stress.

Glutamine has key functions in helping to support gut health and is involved in promoting the cellular turnover of the gut mucosa. The gut lining is renewed every few days, therefore glutamine is critical in helping to support mucosal integrity. Furthermore, glutamine also helps to maintain a strong gut barrier. The small intestine contains a single-layered lining of intestinal epithelium, held together by proteins called tight junctions, which creates a barrier so that pathogens cannot travel across the gut. In periods of illness, stress or inflammation, the gut becomes permeable, causing bacteria to travel across from the gut into the bloodstream and throughout the body, a phenomenon known as leaky gut. Multiple studies have shown that supplementing with glutamine, after stress-inducing activities known to cause gut permeability, has resulted in the maintenance or increase in gut impermeability. Other roles of glutamine include helping to maintain a balanced microbiome, by promoting the growth of good bacteria and reducing strains of bad bacteria.

Furthermore, the combined effects of glutamine such as promoting gut lining turnover, integrity, impermeability and a well-balanced microbiome are likely to be beneficial for those with symptoms associated with Irritable Bowel Syndrome (IBS). Glutamine has been shown to reduce IBS symptom severity score in 80% of participants with post-infectious IBS-D, and in 88% of participants with IBS. Significant improvements in several IBS symptoms have also been observed after glutamine supplementation, including abdominal pain intensity and frequency, abdominal distension as well as stool frequency and consistency.