L-Glutamine Supplements

L-glutamine is an amino acid found in the body, primarily in skeletal muscle. It is also available in a number of common foods and in dietary supplement form. L-glutamine supplements are said to increase muscle mass, as well as treat certain health conditions.

L-glutamine has many functions in the body, including protein synthesis. It is also essential to proper function of the immune system. In addition, L-glutamine appears to play a role in brain function and digestion. 

L-glutamine supplements are purported to enhance exercise performance, as well as help with the following health conditions: anxiety, Crohn's disease, depression, insomnia, and ulcerative colitis.

Additionally, L-glutamine is used to protect against the adverse effects of certain medical treatments, such as chemotherapy. Glutamine (administered by mouth or intraveneously) is also said to help promote healing and reduce the risk of complications in critically ill people who have had traumatic injuries or burns or who have undergone surgery.

Although research on the health effects of taking L-glutamine supplements is limited and often dated, some studies suggest that L-glutamine supplements may offer certain health benefits. Here's a look at several key study findings:

1) Athletic Performance

There's little scientific evidence to support the claim that L-glutamine supplements are beneficial to athletes, according to a 2008 report published in the Journal of Nutrition. The report's authors note that, while many athletes take L-glutamine supplements to protect against exercise-related impairment of the immune system, L-glutamine supplementation does not appear to prevent post-exercise changes in immune function.

To date, few clinical trials have looked at the effects of L-glutamine supplements on sports performance. However, a small study published in the Journal of Sports Medicine and Physical Fitness in 1998 found that L-glutamine failed to enhance high-intensity exercise performance in a group of 10 male athletes.

Related: Nutritional Supplements to Improve Sports Performance.

2) Cancer Treatment Side Effects

Some studies indicate that L-glutamine may be beneficial to people undergoing cancer treatment. For a report published in Alternative Medicine Review in 1999, for instance, scientists looked at the available data on supplemental use of L-glutamine may help offset the muscle glutamine depletion that often occurs in cancer patients. In addition, the report's authors note that L-glutamine may help minimize side effects of chemotherapy and radiation therapy. However, the authors also caution that L-glutamine may stimulate the growth of some tumors.

In a more recent study (published in the journal Colorectal Disease in 2007), researchers found that L-glutamine supplementation decreased post-operative complications and reduced the duration of hospital stay among patients undergoing colorectal surgery for cancer. The study involved 109 patients with colorectal cancer.

An oral gargle with glutamine may help reduce the severity and duration of chemotherapy-induced mucositis.

Glutamine is found in many common plant and animal foods, including:

• barley
• beef
• cabbage
• corn
• cottage cheese
• egg whites
• milk
• peanuts
• pork
• poultry
• raw parsley
• raw spinach
• soy
• yogurt

There's some concern that using L-glutamine supplements in combination with certain medications (including chemotherapy drugs and anti-seizure medications) may produce harmful effects.

Additionally, taking L-glutamine may be harmful to people with certain health conditions, such as liver disease (cirrhosis, hepatic encephalopathy), mania, and seizure disorders.

Supplements haven't been tested for safety and keep in mind that the safety of supplements in pregnant women, nursing mothers, children, and those with medical conditions or who are taking medications has not been established. You can get tips on using supplements here, but if you're considering using L-gluteamine, talk with your primary care provider first. 

Available for purchase online, L-glutamine supplements are sold in many natural-food stores and in stores specializing in dietary supplements.