Arginine, an amino acid, plays a significant role in the body’s immune response, and recent research suggests that low levels of arginine can leave aging bodies vulnerable to colon cancer and viral infections. According to the report, arginine is part of a protein, MHC-1, that sits on the outside of most cells and helps immune cells mount an appropriate immune response against threats to the cell.
Changes in amino acid levels can affect how cells function, and low levels of arginine can affect the expression of genes that code for MHC-1 in models of colon cancer and respiratory viruses such as influenza and SARS-CoV-2, the virus that causes COVID-19.
A team led by researchers at Rockefeller University found that low levels of arginine affect the expression of genes that code for MHC-1 in models of colon cancer and respiratory viruses. When arginine levels are low, fewer MHC-1 proteins are made, and cells grown in the lab showed that fewer T cells are called to destroy the affected and infected cells.
The results suggest that increasing arginine intake could help keep one’s immune system strong, and that an age-related decrease in arginine may be the reason why older people have higher mortality rates when they have respiratory viruses like influenza and SARS-CoV-2.
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First author Qiushuang Wu, a postdoctoral fellow at Rockefeller, used mouse models to test the effect of different levels of arginine in the diet on the risk of colon cancer. Mice with lower levels of dietary arginine developed more tumors than those whose diet contained higher levels of arginine.
Wu also found that mice fed an arginine-rich diet had milder symptoms after viral infection, and that giving mice arginine after they were infected with the influenza virus also improved their outcomes.
The researchers hope that arginine supplementation may offer humans the same benefits as those seen in mice, and that it could be tested in patients receiving immunotherapies or given to at-risk patients who have been exposed to viral pathogens like flu or COVID.
Tavazoie said, “A well-balanced diet may prevent arginine deficiency,” and many high-protein foods are rich in arginine, including nuts, meats, seafood, legumes, and grains.
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For those hoping to strengthen their bodies’ immune responses, Tavazoie noted that foods such as walnuts, almonds, pumpkin seeds, chicken, turkey, tuna, salmon, shrimp, chickpeas, lentils, soybeans, brown rice, and oats are all good sources of arginine.
They are hopeful that therapeutic and preventative studies can be done soon to explore the potential benefits of arginine supplementation for human health.
It is published in Cell.
