May 19, 2014
High-Protein Diets and Longevity
A recent study of 6,381 adults aged 50 and over from the NHANES III suggests that whether or not to consume high amounts of protein may vary according to one’s age.During the study, subjects consumed 1,823 calories on average per day, of which the majority came from carbohydrates (51%) followed by fat (33%) and protein (16%) with most of it (11%) derived from animal protein. The percent of calorie intake from protein was used to categorize subjects into a high-protein group (20% or more of calories from protein), a moderate-protein group (10-19% of calories from protein) and a low protein group (less than 10% of calories from protein).
Mortality was followed via the National Death Index until 2006, which provides timing and cause of death. The 18-year follow-up period covered 83,308 total person-years with 40% overall mortality; 10% was due to cancer, 19% cardiovascular disease, and 1% diabetes. Members of the study aged 50-65 in the high protein category reported a 75% increase in overall mortality and a 4-fold increase in cancer death risk during the following 18 years. These associations were either abolished or attenuated if the proteins were plant-derived. Conversely, high protein intake was associated with reduced cancer and overall mortality in respondents over 65. There was a 5-fold increase in diabetes mortality across all ages for those consuming high-protein diets. These results suggest that low protein intake during middle age followed by moderate to high protein consumption in older adults may optimize health span and longevity.
These data suggest that people should shift their dietary patterns in two key ways. First, patients younger than 65 should be discouraged from eating high-protein diets, especially diets high in animal protein. They should be encouraged to shift toward vegetable protein. Second, patients over 65 should be encouraged to consume more protein as it reduces overall and cancer mortality unless at high risk for diabetes.
Levine ME, Suarez JA, Brandhorst S, et al. Low protein intake is associated with a major reduction in IGF-1, cancer, and overall mortality in the 65 and younger but not the older population. Cell Metab, 2014;19(3): 407-417