This study of more than 1,000 older adults suggested that men who ate the most meat and fish reduced their odds of mental and physical decline by 39 percent, compared with men who ate the least animal protein, CBS News reported.
But the same association was not seen in women. Nor were the same benefits linked to proteins from plants, the researchers found.
However, the study doesn't actually prove that eating meat and fish caused the men's health improvements, or that low animal protein intake contributes to early decline.
Lona Sandon, an assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center at Dallas, said that it is an observational study that simply shows a relationship between protein and functional decline.
It does not prove cause and effect, Sandon said.
Still, research indicates adequate protein intake is important as people age, Sandon noted.
The ability to process protein may decline in old age. As a result, protein requirements may increase, the study suggested.
The research is published in the Journal of the American Geriatrics Society.