Controlling protein intake may be key to a long and healthy life

While it’s clear that diet can affect longevity, there’s great uncertainty about which combinations of foods are best for attaining a long and healthy life. Now two groups of researchers publishing in the March 4 issue of the Cell Press journal Cell Metabolism each suggest that low protein intake may be a key factor, at least until old age. The first study suggests that consuming moderate to high levels of animal protein prompts a major increase in cancer risk and mortality in middle-aged adults, while elderly individuals have the opposite result. Meanwhile, the second team of researchers found that a high-protein, low-carbohydrate diet led to a shorter lifespan in mice. Both studies find that not all calories are created equal—diet composition and animal protein intake are key players in overall health and longevity.

“We studied simple organisms, mice, and humans and provide convincing evidence that a high-protein diet—particularly if the proteins are derived from animals—is nearly as bad as smoking for your health,” says the University of Southern California’s Dr. Valter Longo, who is the senior author of one of the papers.

By analyzing information on 6,831 middle-aged and older adults participating in NHANES III, a nationally representative dietary survey in the United States, Dr. Longo and his team found that individuals aged 50