Some research suggests that cancer cells can use amino acids, such as L-glutamine, as an energy source,. This may sometimes appear concerning at first because of the idea that it could feed or stimulate cancer growth. However, it is important to keep in
mind that cancer can grow on just about any food source - including proteins, carbohydrates and fats. It would be impossible to avoid all of these because that would mean avoiding all food entirely - which is not safe or sustainable. Cancer cells suck up nutrients faster than the rest of the cells in the body, which can deprive the body of essential nutrients.
L-glutamine’s long history of use in the context of cancer has helped to contribute to its safety and efficacy. It has been used for many years as an emergency energy supply for the body in times of stress to ensure the body has enough fuel to keep essential processes going (immunity, digestion, brain, nervous system, liver, lungs etc) and prevent frailty. However, at the end of the day, it doesn’t matter exactly what L-glutamine does - we just need to know whether L-glutamine might help improve outlook and longevity - which the following studies can help clarify:
1. A 2022 study in patients with colon cancer, patients who supplemented glutamine had a trend towards improved survival (77% versus 64% in patients who did not supplement) (NS)
2. A 2017 study found reduced weight loss and digestive irritation in those who supplemented compared to those who did not. By 13 months, the glutamine group had double the proportion of survivors compared to those who did not supplement.
3. A 2020 study compared two groups, one with diet alone and the other with diet + a set of supplements including glutamine. The glutamine group had 61% survival at 2-years, versus a 47% survival rate in the diet-only group.
4. A 2012 study found a small trend towards improved survival and improved disease stability with glutamine compared to no glutamine.
5. A 2019 study found a 16% increase in the amount of time before progression with glutamine, compared to no glutamine.
6. A 2019 study found that patients who had higher blood levels of l-glutamine before treatment had a 90.1% 5-year survival rate compared to 60.1% in those with low levels.
In addition to the above, data suggests that when the body is supplied with nutrients it needs, the body can have the energy and fuel to battle against toxicities that can develop during treatment. Here is the research that helps clarify L-glutamine’s role in preventing side effects:
1. A 2007 study on patients taking oxaliplatin found that the L-glutamine group had half the frequency of peripheral neuropathy compared to the group that did not supplement.
2. A 2004 study on patients taking paclitaxel found that the group that supplemented L-glutamine alongside had less peripheral neuropathy, improved strength and sensation compared to the no l-glutamine group.
3. A 2016 study found less weight loss and esophagitis.
Before taking any supplements, it's crucial to consult with a naturopath or health care professional. This is particularly true for individuals undergoing conventional cancer treatments, as there is a greater risk of interactions with medications. Additionally, supplements may have distinct interactions depending on the type of cancer. Other coexisting medical conditions may also be exacerbated by certain supplements.
 Yuan L, Sheng X, Willson AK, Roque DR, Stine JE, Guo H, Jones HM, Zhou C, Bae-Jump VL. Glutamine promotes ovarian cancer cell proliferation through the mTOR/S6 pathway. Endocr Relat Cancer. 2015 Aug;22(4):577-91. doi: 10.1530/ERC-15-0192. Epub 2015 Jun 4. PMID: 26045471; PMCID: PMC4500469.  Cha YJ, Kim ES, Koo JS. Amino Acid Transporters and Glutamine Metabolism in Breast Cancer. Int J Mol Sci. 2018 Mar 19;19(3):907. doi: 10.3390/ijms19030907. PMID: 29562706; PMCID: PMC5877768.  Ameliorative Potential of L-Alanyl L-Glutamine Dipeptide in Colon Cancer Patients Receiving Modified FOLFOX-6 Regarding the Incidence of Diarrhea, the Treatment Response, and Patients’ Survival: A Randomized Controlled Trial. by Nesreen M. Sabry 1ORCID,Tamer M. Naguib 2,Ahmed M. Kabel 3,*ORCID,El-Sayed Khafagy 4,5ORCID,Hany H. Arab 6 andWalid A. Almorsy 1  Gul K, Mehmet K, Meryem A. The effects of oral glutamine on clinical and survival outcomes of non-small cell lung cancer patients treated with chemoradiotherapy. Clin Nutr. 2017 Aug;36(4):1022-1028. doi: 10.1016/j.clnu.2016.06.012. Epub 2016 Jun 23. PMID: 27373496.  Chitapanarux I, Traisathit P, Chitapanarux T, Jiratrachu R, Chottaweesak P, Chakrabandhu S, Rasio W, Pisprasert V, Sripan P. Arginine, glutamine, and fish oil supplementation in cancer patients treated with concurrent chemoradiotherapy: A randomized control study. Curr Probl Cancer. 2020 Feb;44(1):100482. doi: 10.1016/j.currproblcancer.2019.05.005. Epub 2019 May 23. PMID: 31146957.  Topkan E, Parlak C, Topuk S, Pehlivan B. Influence of oral glutamine supplementation on survival outcomes of patients treated with concurrent chemoradiotherapy for locally advanced non-small cell lung cancer. BMC Cancer. 2012 Oct 31;12:502. doi: 10.1186/1471-2407-12-502. PMID: 23113946; PMCID: PMC3529187.  Chang SC, Lai YC, Hung JC, Chang CY. Oral glutamine supplements reduce concurrent chemoradiotherapy-induced esophagitis in patients with advanced non-small cell lung cancer. Medicine (Baltimore). 2019 Feb;98(8):e14463. doi: 10.1097/MD.0000000000014463. PMID: 30813149; PMCID: PMC6408144.  Ling HH, Pan YP, Fan CW, Tseng WK, Huang JS, Wu TH, Chou WC, Wang CH, Yeh KY, Chang PH. Clinical Significance of Serum Glutamine Level in Patients with Colorectal Cancer. Nutrients. 2019 Apr 21;11(4):898. doi: 10.3390/nu11040898. PMID: 31010101; PMCID: PMC6521237.  Wang WS, Lin JK, Lin TC, Chen WS, Jiang JK, Wang HS, Chiou TJ, Liu JH, Yen CC, Chen PM. Oral glutamine is effective for preventing oxaliplatin-induced neuropathy in colorectal cancer patients. Oncologist. 2007 Mar;12(3):312-9. doi: 10.1634/theoncologist.12-3-312. PMID: 17405895.  Stubblefield MD, Vahdat LT, Balmaceda CM, Troxel AB, Hesdorffer CS, Gooch CL. Glutamine as a neuroprotective agent in high-dose paclitaxel-induced peripheral neuropathy: a clinical and electrophysiologic study. Clin Oncol (R Coll Radiol). 2005 Jun;17(4):271-6. doi: 10.1016/j.clon.2004.11.014. PMID: 15997923.  Gul K, Mehmet K, Meryem A. The effects of oral glutamine on clinical and survival outcomes of non-small cell lung cancer patients treated with chemoradiotherapy. Clin Nutr. 2017 Aug;36(4):1022-1028. doi: 10.1016/j.clnu.2016.06.012. Epub 2016 Jun 23. PMID: 27373496.