Simple Supplement Could Help Your Immune System, Mouse Study Finds

What the mouse experiments showed

In the experiments, mice given more dietary arginine formed fewer colon cancer tumors. They also had milder influenza and SARS-CoV-2 infections.

Giving arginine after mice had already caught influenza also improved their outcomes, the team reported.

The immune protein at the center

Sohail Tavazoie, who directs the Elizabeth and Vincent Meyer Laboratory of Systems Cancer Biology at Rockefeller, led the work. His lab has studied arginine and cancer for years. In 2023, it found that depriving colon cancer cells of arginine caused them to accumulate more genetic mutations.

The new study points to a second effect. When arginine runs short, cells struggle to make enough of an immune protein called MHC-1. The protein works as a warning system, helping immune cells spot cancerous changes and viral infections.

Without enough MHC-1, abnormal or infected cells may become harder to detect. The researchers found that a moderate amount of arginine, comparable to what a couple of over-the-counter supplement tablets provide, helped restore production of the protein.

"Our work reveals how a lack of arginine interferes with the immune system, and suggests that upping arginine intake could prove beneficial," said first author Qiushuang Wu, a postdoctoral researcher in the lab. "Perhaps that means it could be used in combination with other therapies to treat both cancer and viral infections."

Tavazoie said arginine supplements could be tested in patients receiving immunotherapies, or given to high-risk groups exposed to viral pathogens. "Considering that arginine is inexpensive and readily available, we hope that therapeutic and preventative studies could be undertaken soon," he said.

The results come from mice, and the researchers stress that further research in humans is needed to learn whether the benefits carry over to people.