The substitution of plant protein for animal protein, especially that from processed red meat, is associated with lower mortality, while high animal protein intake is positively associated with mortality, according to a recent study. This cohort study of US health care professionals included 131,342 participants (64.7% women, 35.3% men, mean age 49 years). Researchers found:

• Median protein intake was 14% for animal protein and 4% for plant protein.

• Animal protein intake was weakly associated with higher mortality, especially cardiovascular mortality (HR, 1.08 per 10% energy increment).

• Conversely, plant protein was associated with lower mortality (HR, 0.90 per 3% energy increment).

• These associations were confined to individuals with a least 1 lifestyle risk factor.

• Replacing animal protein of various origins with plant protein was associated with lower mortality.

Citation: Song M, Fung TT, Hu FB, et al. Association of animal and plant protein intake with all-cause and cause-specific mortality. [Published online ahead of print August 1, 2016]. JAMA Intern Med. doi:10.1001/jamainternmed.2016.4182.

Commentary: Those whose protein source is derived primarily from vegetables do appear to be having a healthier diet than those who eat meat. After adjusting for other health habits that are more common among those who eat more vegetables, higher animal protein intake was associated with higher mortality and higher CV mortality. Interestingly, this association was only seen in those who also had 1 additional CV risk factor. What this likely means is that increasing vegetable-based protein in one’s diet is a strategy that can be recommended for those at elevated CV risk. It is important to note that most of the differences between animal- and plant-based diets were confined to intake of red meat, primarily processed red meat, and that intake of fish and poultry were not associated with adverse outcomes. The importance of macronutrient source, and the benefits shown in this study of plant-based protein sources, adds to the evidence from other studies supporting the health benefits of eating a diet rich in plant-based protein. —Neil Skolnik, MD