The impact of a single amino acid on our immune system — Arginine

All of the proteins in our body consist of chains of amino acids. There are 20 standard amino acids that are used to build proteins in the human body, and one of these amino acids, arginine, plays a critical, yet complex, role in our immune system. A recent online publication from The Rockefeller University highlighted the fact that arginine plays an essential role in fighting tumors and viral infections. Specifically, deficiency of arginine was implicated in the development and worsening of colon cancer, as well as in influenza and SARS-CoV-2. The authors’ research, published in the journal Cell, highlighted that the likely mechanism at play relies on the fact that nearly all the cells in our body rely upon major histocompatibility complexes (MHC 1, specifically) to present intracellular proteins to our immune cells, thereby facilitating the recognition of foreign proteins (either viruses or abnormal cancer producing proteins) and targeting those cells for destruction. Since arginine is so prevalent in MHC 1, deficiency of this amino acid can impair anti-viral immunity against influenza and SARS-CoV-2 (COVID), as well as increase colon tumor development (“tumorigenesis”). Supplementation with arginine reversed these processes!

While this sounds fantastic, and one might jump to the conclusion that giving supplemental arginine to all cancer patients would be helpful, the story is much more nuanced and complex! An excellent review article published in Immune Networks last year emphasized that arginine has a role both in battling tumors (anti-tumor), as well as in promoting tumor development (tumor-promoting)! Check out the excellent image from that article here.

The authors emphasize that arginine exerts dual actions in cancer cells: promoting cancerprogression via nutritional support, while also exerting anti-cancer effects through activation of the immune system, and inducing apopotosis (cell death).

So supplementation with arginine may not be the “cure all” for infections and cancer, but there is likely little harm when taking in extra arginine when infected with the flu or COVID. Supplements can be found here. I look forward to future research analyzing the role of arginine in specific cancer treatment protocols.