Glutamine and cancer

Glutamine’s role in gut health and mouth sores 

Glutamine is a type of protein building block (amino acid) that your body makes naturally. It’s the most common amino acid in your blood and is especially important for the cells that line your stomach and intestines. These cells use glutamine as their main fuel source to stay healthy and repair themselves.

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During chemotherapy or radiation, your body’s demand for glutamine increases. Treatments can damage the lining of the mouth, throat, and gut, leading to a painful condition called mucositis (mouth sores). This can make eating, drinking, and swallowing difficult. When your body is under this kind of stress, it may not make enough glutamine on its own, this is when extra glutamine might help.

Studies show that glutamine supplements may reduce the severity of mouth sores and help the gut heal faster. Reviews of clinical trials have found that participants who took glutamine during treatment had fewer severe mouth ulcers than those who didn’t. 

This is largely due to glutamine’s ability to help the body repair damaged tissues, strengthen the gut lining, and reduce inflammation. 

By protecting the mouth and promoting healing, glutamine can help reduce discomfort, improve eating, and support better nutrition during treatment. However, benefits vary according to the type of cancer, the dose used, and when glutamine was started.

Note: Glutamine should be used under the guidance of your cancer care team.

When and how glutamine is used in cancer care

Glutamine is recommended during cancer treatment, not to treat the cancer itself, but to help the body cope better with side effects, such as mouth sores, gut inflammation, or poor nutrition.

It’s most often used for patients receiving radiation or chemotherapy, especially in cancers of the head, neck, and digestive system. 

Doctors and dietitians may recommend it before treatment starts and for a short time afterwards to support healing. It can be taken as a powder mixed with water or as part of a special medical nutritional supplement drink.

There is some concern that glutamine may feed cancer, as laboratory studies have shown that certain cancer cells can use glutamine for growth. However, research in humans hasn’t demonstrated that standard supplement doses of glutamine promote cancer growth. The doses used in supportive care are far lower than those required to stimulate tumour growth. 

Your oncologist and dietitian will carefully decide whether glutamine is right for you, depending on the type of cancer, treatment plan, and your overall health. It’s important not to take any supplement, including glutamine, without your care team’s approval.

Types of glutamine supplements

If your doctor or dietitian recommends glutamine, it’s important to use medical-grade products. These products are tested for purity and safety and are different from general sports or fitness supplements.

Medical-grade glutamine comes in various forms:

• Powder: The most common form. It’s usually mixed into water or juice and taken a few times a day.
• Tube-feeding formulas: For people who can’t eat by mouth, some feeding formulas contain added glutamine.
• Combination products: Ready-to-drink oral nutritional supplements where glutamine is combined with other nutrients, such as arginine or antioxidants, to support tissue repair and immune function.

The dose of glutamine varies between individuals. The typical dose recommended is 0.3-0.5g per kg of body weight per day, approximately 15-30g of glutamine per day, divided into smaller servings. However, the correct dose will depend on your treatment, side effects, nutritional status, and weight.

Glutamine is generally well tolerated; however, some individuals may occasionally experience mild stomach discomfort. If you notice any unusual symptoms, let your care team know. Never start or change supplements on your own, always seek guidance from your dietitian.

Taking care of your nutrition during cancer treatment is one of the most powerful ways to support your strength, comfort, and healing. Glutamine can sometimes be a valuable part of that plan, but always as part of a co-ordinated approach with your oncology and dietetic team.

References

• McQuade RM et al. Cancers (2024);16(5):1057.
• Lin J et al. Supportive Care in Cancer (2021);29:7055–7066.
• Hong J et al. American Journal of Clinical Nutrition (2022).
• Yang L et al. BioSignaling (2024).
• Clinical Nutrition ESPEN (2021);46:360–368.
• Frontiers in Pharmacology (2024).