Are you tired of me talking about the benefit of plant-based diets? I hope you aren’t, because I don’t think I’ll ever get tired of it:
Association of Animal and Plant Protein Intake With All-Cause and Cause-Specific Mortality, JAMA Internal Medicine, Online 1 August 2016
Objective: To examine the associations of animal and plant protein intake with the risk for mortality.
Design, Setting, and Participants: This prospective cohort study of US health care professionals included 131 342 participants from the Nurses’ Health Study (1980 to end of follow-up on June 1, 2012) and Health Professionals Follow-up Study (1986 to end of follow-up on January 31, 2012). Animal and plant protein intake was assessed by regularly updated validated food frequency questionnaires.
Conclusions and Relevance: High animal protein intake was positively associated with mortality and high plant protein intake was inversely associated with mortality, especially among individuals with at least 1 lifestyle risk factor. Substitution of plant protein for animal protein, especially that from processed red meat, was associated with lower mortality, suggesting the importance of protein source.
This was a big study. It was prospective (which is good because there is less chance for confounding than with a retrospective study). There were multiple dietary assessments, not just one at the beginning. It was long. There were a lot of adjustments for possible confounders. (Like, maybe it was the fiber in plant food that helped? No, adjusted.)
The strengths of the present study included the large sample size, repeated dietary assessments, and high follow-up rate of the 2 well-established cohorts for up to 32 years. Moreover, we collected detailed data on a wide spectrum of lifestyle factors that allowed for rigorous confounding adjustment and subgroup analysis.
And what did they find? The more animal protein people ate, the sooner they died.