High-protein diet linked to lower risk for death

Diets high in protein were associated with a lower risk for all-cause mortality, according to a study published in the BMJ.

“Findings on the association between total protein intake and longevity are still controversial,” Sina Naghshi, of the Students’ Scientific Research Center and the department of clinical nutrition in the School of Nutritional Sciences and Dietetics at Tehran University of Medical Sciences, Iran, and colleagues wrote. “Total protein intake was associated with a decreased risk of mortality in some investigations, but others failed to find such evidence.”

Naghshi and colleagues conducted a systematic review and meta-analysis of prospective cohort studies published through December 2019 that examined associations between protein intake and all-cause mortality, cardiovascular mortality and cancer mortality in adults aged 18 years and older.

A total of 32 studies were included in the systematic review and 31 studies were included in the meta-analysis.

In the 3.5 to 32 years of follow-up data, Naghshi and colleagues identified 113,039 deaths among the 715,128 participants. Of those deaths, 16,462 were attributed to cardiovascular disease, and 22,303 were attributed to cancer.

Naghshi and colleagues found that protein intake was associated with a lower all-cause mortality risk, determining that there was a pooled effect size of 0.94 (95% CI, 0.89-0.99) when comparing the highest and lowest levels of protein intake.

They also determined that although there was not a significant association between animal protein intake and CV mortality, there was between plant protein and CV mortality, with a pooled effect size of 0.88 (95% CI; 0.80-0.96) when comparing the highest and lowest levels of plant intake.

Plant protein intake was also associated with a lower risk for all-cause mortality, with a pooled effect size 0.92 (95% CI, 0.87-0.97) between the highest and lowest intakes.

According to the researchers, there was not a significant association between plant protein intake and cancer mortality.

Naghshi and colleagues also reported that there was a significant dose-response relationship between plant protein intake and all-cause mortality, with the addition of 3% energy intake from plant protein each day resulting in a 5% lower risk for all-cause mortality.

“These findings have important public health implications as intake of plant protein can be increased relatively easily by replacing animal protein and could have a large effect on longevity,” Naghshi and colleagues wrote, noting that the study supports existing recommendations to increase plant protein consumption.