High-Protein Diets in Middle Age Might Shorten Life Span
But same study found the reverse was true when people reached old age
By Robert Preidt
TUESDAY, March 4, 2014 (HealthDay News) -- Millions of middle-aged Americans chow down each day on steaks, cheeseburgers and other protein-rich fare.
Now two studies find that diets high in meat and cheese, when eaten in middle age, might shorten people's life spans.
However, in a surprise twist, the same research team found that eating lots of animal-based protein in old age might actually do the opposite.
"The research shows that a low-protein diet in middle age is useful for preventing cancer and overall mortality [death]," study co-author Eileen Crimmins, the AARP Chair in Gerontology at the University of Southern California, said in a university news release. "However, we also propose that at older ages, it may be important to avoid a low-protein diet to allow the maintenance of healthy weight and protection from frailty."
The findings were published March 4 in the journal Cell Metabolism
In the study, the researchers looked at data on more than 6,800 middle-aged and older adults in the United States. They found that 50-year-olds who got more than 20 percent of their calories from animal protein -- mainly meat or dairy products -- had a fourfold increased risk of death from cancer or diabetes. And they had a nearly twofold increased risk of death from any cause over the next 18 years, compared to people on more low-protein regimens.
Even middle-aged people who consumed only "moderate" levels of animal protein had a threefold increased risk of death from cancer, the researchers reported.
This increased risk of death was much lower or non-existent in 50-year-olds who ate a diet high in protein sourced mainly from plants, the researchers added.
However, the study also found that people older than 65 who consumed high amounts of animal protein had a 60 percent lower risk of dying from cancer and a 28 percent lower risk of death from any cause, compared to people who shied away from meat and dairy at this age. Similar benefits were seen in seniors who had moderate levels of protein intake.