Glutamine: Does It Have Any Benefits?

Glutamine is the most abundant amino acid in the human body. It is highly versatile with a broad range of functions and is vital for maintaining good health.

Glutamine is a conditionally essential amino acid. This means that our bodies can usually produce it from other amino acids. However, under certain conditions, our glutamine requirements increase, and we may need additional sources.

This article explains glutamine’s specific role in health and disease, as well as its potential benefits. We also discuss when supplementation might be helpful, including dosage, side effects, and more.

Uses and Benefits

One of glutamine’s most significant roles is in metabolism.

It helps to maintain our levels of adenosine triphosphate (ATP), our cells’ primary energy source. It does this by increasing insulin sensitivity and enhancing glucose uptake. It also facilitates a process called gluconeogenesis, the production of glucose from non-carbohydrate molecules.

Many different cell types rely on glutamine to provide them with energy. However, immune cells are among the most significant consumers.

Several cell types, including lymphocytes, macrophages, and neutrophils, require sufficient glutamine to function optimally. Therefore, the amino acid also plays a crucial role in immunity.

Other functions include regulating the inflammatory response and protecting tissues from damage. Glutamine influences the activity of cytokines, chemical messengers that control inflammation.

It is also involved in protein synthesis and promotes new cell growth, contributing to tissue integrity and wound healing.

Glutamine also acts as a precursor to the neurotransmitters glutamate and GABA and a chemical called glutathione, which has cell-protective properties. Therefore, this amino acid can influence both physical and psychological health.

Because it has such a vast range of functions, some people believe it is useful to take a glutamine supplement. Let’s look closer at some of the potential benefits of glutamine for specific aspects of health and disease.

Athletic Performance

Glutamine is highly concentrated in our skeletal muscle, where it acts as a valuable fuel source. It also protects the muscles from damage by modulating inflammatory activity.

Therefore, some experts have suggested that glutamine supplements could aid athletic performance. Theoretically, they should help to prevent fatigue, improve endurance, and assist in post-training muscle recovery.

Glutamine levels fall during intense exercise. According to several sources, this is why overtraining can impair immune function.

Indeed, there is some evidence that glutamine levels fall during intense exercise. According to several sources, this is one reason why overtraining can impair immune function. Unfortunately, though, research on the subject has failed to produce consistent results.

For example, a 2008 publication concluded that glutamine supplements were unlikely to provide substantial fluid balance or immunity benefits. However, the authors stated that the amino acid might enhance anabolic processes, i.e., muscle growth.

Meanwhile, a 2019 review found that while glutamine improved fatigue and muscle damage markers, it did not impact overall performance.

Gut Health

Glutamine also plays a crucial role in gut health.

The cells that line the intestines have a high turnover rate, renewing themselves every 4-5 days. This process requires a precise balance between the growth of new cells and the destruction of old ones. Glutamine helps to maintain this balance.

It also reduces inflammation and protects intestinal cells from damage to maintain the integrity of the digestive tract. Therefore, some have hypothesized that it could help treat inflammatory bowel disease (IBD), such as ulcerative colitis.

However, while animal experiments suggest that supplements could be beneficial, human studies have produced inconsistent results. Therefore, the current evidence does not support using glutamine to treat IBD, and further research is required.

Cancer Treatment

Cancer is one of the conditions under which glutamine becomes an essential amino acid. This means that the body cannot produce enough to meet its needs and may require additional intake.

There is a suggestion that glutamine could benefit cancer patients by increasing immune function. There is also some evidence that it could help to reduce some of the side effects of chemotherapy.

However, experts have recommended that cancer patients take glutamine supplements with caution. Just as healthy cells use the amino acid as an energy source, so do cancerous ones. Therefore, significant increases could potentially fuel tumor growth.

Individuals with a cancer diagnosis considering supplementation should consult their oncologist to discuss the possible benefits and risks.

Critical Care

Glutamine is also an essential amino acid for many critical care patients, including those with:

• Severe burns
• Physical trauma
• Sepsis
• Post-operative complications

Approximately 38% of intensive care unit (ICU) patients are glutamine deficient on admission, leading many experts to recommend supplementation. Indeed, the amino acid is a common ingredient in these patients’ nutritional formulas.

However, while some believe that it is indispensable for all patients, others suggest case-by-case assessment. There is evidence that certain ICU patients actually have abnormally high glutamine levels, meaning supplementation could be harmful.

Sickle Cell Disease

The FDA approved L-glutamine (Endari) as a treatment for sickle cell disease in 2017. It is licensed for patients aged five and over to reduce sickle cell crises and acute complications such as pain.

Endari is a pharmaceutical-grade form of L-glutamine and is only available with a prescription.

Research has shown that patients taking glutamine have fewer hospitalizations, fewer cumulative hospital days, and a lower incidence of acute chest syndrome.

Endari is a pharmaceutical-grade form of L-glutamine and is only available with a prescription.

Side Effects

Most people can take relatively high doses without experiencing adverse effects. However, some possible glutamine side effects include:

• Constipation
• Nausea
• Headaches
• Abdominal pain
• Back, leg, feet, arm, or hand pain
• Cough

Moreover, some groups of people should not take glutamine, including people with kidney disorders. Anyone with a pre-existing medical condition should consult their physician before beginning supplementation.

Glutamine Interactions

Glutamine may increase the risk of seizures in some individuals. Certain anti-seizure medications can also interact with glutamine, potentially reducing their effectiveness.

This interaction occurs because of glutamine’s relationship with the excitatory neurotransmitter glutamate, which plays a role in the pathology of epilepsy.

Dosage

Research suggests that a glutamine dosage of up to 30g daily is safe for short-term use. However, there is no standard dose, and the optimal amount will depend upon several factors.

The reason for using glutamine is one such factor. For example, athletes tend to use 20–30g daily for several days. Meanwhile, sickle cell patients can take 10–30g twice daily, depending on their age and body weight.

Data on the safety of long-term use in healthy individuals is lacking.

Glutamine Sources

Under normal circumstances, the body can synthesize glutamine from the branched-chain amino acids, leucine, isoleucine, and valine. Some foods also contain glutamine, including:

• Beef
• Milk
• Rice
• Corn
• Tofu
• Eggs

People who are seriously ill might be unable to make enough glutamine and may benefit from a supplement. Supplements are also popular among athletes, who have higher-than-average amino acid requirements.

Glutamine supplements come as tablets, capsules, or powder, and there are many different products on the market. They are primarily available in the form of L-glutamine. However, some other supplements, including whey powder and protein hydrolysates, are also good sources.

Consumers should perform thorough research to ensure they receive high-quality goods from a reputable brand. To learn more, check out our review: What Are the Best Amino Acids? Our Top Picks.

Final Thoughts on Glutamine

Glutamine is an amino acid with numerous functions in the body. It plays a role in metabolism, immunity, cell health, protein synthesis, and more.

Most people can obtain enough glutamine by eating a balanced, high-protein diet. However, some people may benefit from supplementation.

Although they are generally well-tolerated, supplements can cause some side effects and are not suitable for everyone. Therefore, individuals should consult a healthcare professional before using them for the first time.