Diets high with plant protein are associated with a lower risk of death from any cause, finds a meta-analysis published in The BMJ.
Diets with low carbohydrates and high protein have become the food trend in recent decades (Shan et al., 2019). Primary reasons behind the popularity of a high protein diet may be associated with its effect on weight loss, increased power, and integrity of muscle mass (Westerterp-Plantenga et al., 2012, Leidy et al., 2015).
Diets with a higher amount of protein, particularly from plant sources, such as legumes (peas, beans, and lentils), whole grains, and nuts, are related to reduced risk of diabetes, cardiovascular disease, and mortality (Chan et al., 2019). However, some studies failed to draw such a conclusion for animal and plant protein (Sun et al., 2019).
Because of the conflicting data, a group of international scientists based in the USA and Iran, conducted a dose-response meta-analysis (Naghshi et al., 2020) of prospective cohort studies to summarize the association between intake of both plant and animal protein and the risk of mortality from cardiovascular disease, and cancer, the primary cause of 26.9 million deaths worldwide in 2016 (WHO 2016).
The researchers reviewed 32 studies that estimated cardiovascular and cancer mortality risk in adults aged 19 or older. They used a statistical model to compare the effects of the highest versus lowest categories of protein intake and evaluated the dose-response relations between protein intake and mortality.
Of the total 715,128 participants during the follow-up period of 3.5 to 32 years, 113 039 deaths occurred of which 16 429 deaths were from cardiovascular disease and 22 303 from cancer, the study found. The analysis also revealed intake of plant protein was associated with an 8% lower risk of all-cause mortality and a 12% lower risk of cardiovascular disease mortality. However, the consumption of animal protein was not significantly associated with the risk of cardiovascular disease and cancer mortality.
Data obtained from the dose-response analysis showed that an additional 3% of energy from plant proteins a day was associated with a 5% lower risk of death from all causes.
The mechanisms through which plant proteins could affect human health are not well known. It is believed that once the plant protein is digested, it produces beneficial health peptides that favorably change cholesterol and blood sugar levels and maintain blood pressure.
However, animal protein consumption was associated with increased concentrations of biomarkers that are associated with an increased risk of age-related diseases, such as cancers.
“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”—quoted the study in conclusion.