Does glutamine supplementation contribute to the development of cancer?

From the Guidelines

Glutamine does not cause cancer, and its supplementation is not recommended for cancer prevention or treatment without consulting an oncologist, as the current evidence is insufficient to support its effectiveness in improving clinical outcomes in cancer patients. Glutamine is an amino acid naturally produced in the body and found in many foods, serving as an important energy source for cells, particularly those that divide rapidly like immune and intestinal cells. While cancer cells do use glutamine for energy and growth, consuming glutamine in food or supplements does not initiate cancer development 1. In fact, glutamine supplements are sometimes recommended for cancer patients experiencing muscle wasting or intestinal side effects from treatments. The relationship between glutamine and cancer is complex - while existing cancer cells may utilize glutamine, this doesn't mean glutamine consumption causes cancer to develop in healthy individuals.

The body tightly regulates glutamine levels, and normal dietary intake or supplementation within recommended doses is considered safe for most people 1. However, the evidence on the use of glutamine supplementation in cancer patients is contradictory, and there are insufficient consistent clinical data to recommend glutamine supplementation during conventional cytotoxic or targeted therapy 1. A systematic review and meta-analysis of 8 RCTs on the prevention of chemotherapy-induced diarrhea reported a significant shortening of the duration of diarrhea, but no effect on diarrhea severity 1.

Some key points to consider when evaluating the use of glutamine in cancer patients include:

• The lack of information on glutamine effects on tumor response 1
• The potential benefits of glutamine supplementation in reducing chemotherapy-induced mucosal inflammation, vomiting, and diarrhea 1
• The importance of individualized nutrition support, including counseling, oral nutritional supplements, enteral nutrition, and/or parenteral nutrition, to avoid or minimize further loss of weight and body cell mass 1
• The need for patients to be screened and assessed for impending or overt malnutrition at admission and after that monitored weekly during their treatment for adequate nutrient intake, metabolism, and physical activity 1

If you have active cancer or are undergoing cancer treatment, it's always best to consult with your oncologist before taking glutamine supplements, as individual circumstances may vary 1.

From the Research

Glutamine and Cancer

• The relationship between glutamine and cancer is complex, with some studies suggesting that glutamine can support tumor growth, while others indicate that it may have beneficial effects on the host metabolism and clinical situation of cancer patients 2, 3.
• Glutamine is a major dietary amino acid that is both a fuel and nitrogen donor for healing tissues damaged by chemotherapy and radiation, and evidence supports its benefit in reducing symptoms and improving quality of life of cancer patients 4.
• Cancer cells undergo metabolic reprogramming targeting glutamine, increasing its uptake to meet their rapid proliferation demands, and glutamine metabolism is reprogrammed in cancer cells to provide carbon and nitrogen for biosynthesis 5, 6.

Effects of Glutamine on Cancer Cells

• Glutamine can support the metabolism of tumor-bearing hosts and ameliorate gastrointestinal toxicity of therapeutic measures, but its effects on tumor growth are still unclear 2.
• Some studies suggest that glutamine supplementation can improve host metabolism and clinical situation without increasing tumor growth, while others indicate that it may have potential mechanisms to inhibit cell proliferation and increase apoptosis rate 2, 3.
• The dependence of many hematological and solid tumors on glutamine is associated with mitochondrial glutaminase (GLS) activity, and targeting glutamine metabolism through inhibition of GLS may limit energy availability and increase oxidative stress in cancer cells 5.

Therapeutic Use of Glutamine

• Oral supplementation with glutamine can enhance the immune capabilities of cancer patients, improve the sensitivity to chemotherapy and radiotherapy, and improve prognosis 6.
• Glutamine supplementation in a high protein diet can reduce painful mucosal symptoms and ulceration associated with chemotherapy and radiation in the head and neck region, esophagus, stomach, and small intestine 4.
• The unique metabolism of glutamine in cancer cells, its function in various immune cells, and the impact of inhibitors of glutamine metabolism are areas of ongoing research, with potential for the discovery of new targets and therapeutic approaches 5, 6.