Eating more protein from plant sources is associated with a lower risk of death, while animal protein increases it, especially among adults with unhealthy behavioral habits such as smoking, drinking excess alcohol, being overweight or sedentary, according to a study published in JAMA Internal Medicine.
"While previous studies have focused primarily on the total amount of protein intake, our study looks at which protein sources are healthier," explains Mingyang Song, a researcher at Massachusetts General Hospital.
Researchers from the Massachusetts General Hospital and Harvard Medical School (USA) have used data from two large American dietary studies that have been analyzing the eating habits of the population for up to 32 years.
The results showed that the 131,342 participants ingested an average of 14% animal protein compared to 4% vegetable protein in their diets.
According to the research, a 10% increase in animal protein intake increases the risk of death from cardiovascular diseases by 8% and by 2% from other causes. On the contrary, increasing the consumption of vegetable proteins by 3% reduces the chances of dying from a cardiovascular problem by 12%.
Better fish than red meat
This association between animal protein and risk of mortality only applies to participants with at least one factor associated with unhealthy lifestyles: underweight or overweight; excessive alcohol consumption, smoking or sedentary lifestyle. In fact, the association disappeared in participants with a healthy lifestyle.
Of all the animal protein foods, processed and unprocessed red meats - which include both beef and pork products - are the most harmful.
Substituting 3% of animal protein for calories from plant protein is associated with a lower risk of death from all causes. The odds drop 34% with the substitution of processed red meat, 12% with unprocessed red meat, and 19% with the replacement of eggs.
"People should consider eating more plant protein than animal protein, and among animals, fish and chicken are probably the best option," says Song.
According to the researchers, the study helps public health recommendations now focus on promoting the healthiest protein sources.