Eating more protein from plant sources was associated with a lower risk of death and eating more protein from animals was associated with a higher risk of death, especially among adults with at least one unhealthy behavior such as smoking, drinking and being overweight or sedentary, according to an article published online by JAMA Internal Medicine .
The consideration of food sources is critical to better understanding the health effects of eating protein and fine-tuning dietary recommendations.
Mingyang Song, M.D., Sc.D., of Massachusetts General Hospital and Harvard Medical School, Boston, and coauthors used data from two large U.S. studies that had repeated measures of diet through food questionnaires and up to 32 years of follow-up. They examined hazard ratios (risk) for all-cause and cause-specific mortality in relation to eating animal protein vs. plant protein.
Among 131,342 study participants, 85,013 (64.7 percent) were women and the average age of participants was 49. Median protein intake, measured as a percentage of calories, was 14 percent for animal protein and 4 percent for plant protein.
The authors report:
Limitations include the study's observational design, so residual confounding (other mitigating factors) cannot be excluded.
"Substitution of plant protein for animal protein, especially from processed red meat, may confer substantial health benefit. Therefore, public health recommendations should focus on improvement of protein sources," the study concludes.
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( JAMA Intern Med . Published online August 1, 2016. doi:10.1001/jamainternmed.2016.4182. Available pre-embargo to the media at http://media.jamanetwork.com .)
Editor's Note: The study contains funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
Media Advisory: To contact corresponding study author Mingyang Song, M.D., Sc.D., call Terri Ogan at 617-726-0954 or email togan@partners.org .
JAMA Internal Medicine