RESOLVING THE LEDGER
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0 Share Newsweek is a Trust Project member See more of our trusted coverage when you search. Prefer Newsweek on Google to see more of our trusted coverage when you search. A common amino acid found in protein-rich foods and over-the-counter supplements may play a far bigger role in fighting cancer and viral infections than previously understood, according to new research from Rockefeller University.
The study found that low levels of arginine can prevent cells from producing a protein the immune system relies on to detect cancer and viruses, allowing threats to slip past.
Sohail Tavazoie, who leads Rockefeller University's Elizabeth and Vincent Meyer Laboratory of Systems Cancer Biology, told Newsweek that arginine levels are already known to be low in cancers, and that viruses reduce arginine levels in the tissues they infect. He said arginine also naturally declines in the body with age.
"We have found that these reduced arginine levels reduce the ability of our cells to produce a key protein called MHC-1, which 'presents' abnormal proteins in our cells, such as those from viruses or mutated proteins in cancer cells, to our immune system, so they can be detected and eradicated," Tavazoie said.
He said that supplementing arginine in the diet helped counter the deficiency caused by cancer or viruses, reducing the severity of flu and COVID-19 in the research. Notably, arginine improved influenza outcomes in mice even when given 24 hours after infection. The amount used was equivalent to roughly 10 grams of arginine per day, or about the amount in a couple of standard over-the-counter tablets.
Arginine is an amino acid that helps cells build proteins carrying out a wide range of biological functions. The body produces it naturally , and it is also found in many protein-rich foods. Abnormally low arginine levels have previously been linked to several diseases , including colon cancer.
Building on earlier work showing that arginine deprivation causes colon cancer cells to accumulate more mutations, Tavazoie's team examined whether shifting arginine levels could alter gene expression, a connection that had not been well understood.
Researchers studied several disease models, including colon cancer, influenza and SARS-CoV-2, in cell cultures and identified 414 proteins present at unusually low levels when arginine was scarce. Most matched arginine's already known functions, but three genes responsible for producing MHC-1 stood out.
MHC-1 proteins sit on the surface of cells throughout the body, displaying foreign or abnormal proteins to T cells, which then rally other immune cells to respond. Because MHC-1 requires many arginine building blocks to assemble, the researchers found that when arginine ran short, the ribosomes producing it stalled and could not finish the protein, leaving cells with fewer warning signals to alert the immune system.
Tavazoie said the age-related decline in arginine "could also partially explain the age associated risk of developing colon cancer," as well as increased flu and COVID-19 severity in older adults.
His team is now interested in testing whether arginine supplementation could improve outcomes for flu patients at high risk of severe illness.
Tavazoie, S. F., et al. (2026). Dietary arginine drives codon-dependent MHC class I translation and improves immunity in colon tumorigenesis and respiratory viral infection. Cell . https://doi.org/10.1016/j.cell.2026.07.020.
Contact Newsweek editors on this story: Kara Dolman and Sam Wilson .
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