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L-glutamine is the most abundant free amino acid in human blood plasma and skeletal muscle and has a vital role to play in the health of the gut lining. The gut lining is so much more than just a tube that facilitates the passage of foods into and out of the body; it has a critical and dynamic part to play in supporting overall health.

The gut lining is involved in many vital health functions:

 ✓ Food digestion
 ✓ Nutrient absorption
 ✓ Secretion of important substances such as enzymes
 ✓ An important barrier to prevent harmful substances such as toxins, pathogens and large food particles from passing through into the systemic circulation

Needless to say, your gut lining is crucial and you need to look after it.
Stress, food allergies, alcohol, antibiotics, gut dysbiosis and malnutrition are just some factors that can damage the gut lining and in particular, damage is caused to specialised complexes called ‘tight junctions’ which are an essential part of the structure and function of the gut lining. Once the gut barrier is disrupted, mucosal inflammation and tissue injury occurs and harmful substances are able to move into the systemic circulation. Loss of tight junction integrity and increased intestinal permeability, or ‘leaky gut syndrome’, is known to be associated with the pathogenesis of gastrointestinal problems such as IBD, IBS and coeliac disease, and more widespread chronic health problems too.

Supplementation with l-glutamine is widely considered to be a useful intervention strategy for leaky gut syndrome.
L-glutamine is a ‘conditionally-essential’ amino acid. This means that the body can produce enough to cope with normal everyday functions, however, it requires additional supplies if demand increases. Demand for l-glutamine increases during intense exercise, severe stress, infections, trauma and post-surgery. In these conditions, l-glutamine stores can quickly become depleted and supplementation may become necessary to restore levels and support the gut lining.

L-glutamine reduces intestinal permeability from various stressors and helps to maintain and protect the normal intestinal barrier function.


 • Provides fuel for intestinal mucosal and immune cells
 • Regulates cell proliferation in the gut lining
 • Repairs the gut lining
 • Maintains epithelial tight junction integrity
 • Preserves everyday functions of the gut lining

Research review articles:

 • In a 2012 review article on ‘Intestinal barrier function in health and gastrointestinal disease’, the authors found increasing evidence that increases in intestinal permeability plays a pathogenic role in gastrointestinal health problems such as IBS, IBD and coeliac disease. They also found that deficiencies in glutamine may lead to increased intestinal permeability and that glutamine supplementation can restore intestinal membrane permeability.1

• In an additional 2012 review article on ‘The role of glutamine in the protection of intestinal epithelial tight junctions’, the authors concluded, “there is ample evidence to indicate that L-glutamine is the essential dietary supplement to help maintain mucosal integrity and barrier function under physiologic and pathophysiologic conditions. The human gut has little capacity to synthesise glutamine and therefore it relies on the glutamine supply by other tissues and diet.”2

Whilst l-glutamine isn’t considered to be an essential nutrient, it is quickly depleted by common 21st century conditions such as stress, exercise and infection. Research shows that l-glutamine is a critically important nutrient to protect and maintain a healthy gut lining and a potential useful intervention in leaky gut syndrome.

1. Camilleri M, Madsen K et al. Intestinal barrier function in health and gastrointestinal disease. Neurogastroenterol Motil. 2012 Jun; 24(6): 503-512
2. Rao RK, Samak G. The role of glutamine in the protection of intestinal epithelial tight junctions. J Epithel Biol Pharmacol.  2012 Jan; 5(Suppl 1-M7): 47-54

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