A new protein-focused paper confirms that eating red meat may be linked to a higher risk of death.
The data, which came from the 32-year national Nurses' Health Study and the 26-year Health Professionals Follow-up Study at Harvard, assessed protein intake with frequent questionnaires that participants completed.
However, replacing animal protein in your diet with plant protein is associated with a decreased risk of death, according to the research, which was published in JAMA Internal Medicine on Monday.
Scientists have long connected processed red meats with a wide spectrum of chronic diseases, such as cancer, diabetes and heart disease.
Now, the new paper reveals that these associations may still exist when examining protein intake overall, said Dr. Mingyang Song, a researcher at Massachusetts General Hospital and the Harvard T.H. Chan School of Public Health, who served as lead author of the paper.
"Our findings have important public health implications," he added. "They can help refine the current dietary recommendations about protein intake and really get to the point that it is not only the amount but also the food sources of protein that are critical for long-term health."
A 3% increase in plant protein intake was linked to a 10% decrease in overall mortality and a 12% decrease in cardiovascular mortality.
Why animal protein is linked to mortality and plant protein is linked to a lower risk of death remains largely a mystery, Song said.
According to Kim Robien, associate professor of exercise and nutrition science at George Washington University's Milken Institute School of Public Health:
"The findings confirm what we have been observing from studies using different research approaches," she added. "People who consume their dietary protein primarily from plant foods would be expected to be better able to maintain a healthy weight and have lower risk of chronic diseases such as cardiovascular disease, diabetes and cancers."
So then, what can you consume to replace animal protein with plant protein in your daily diet?
"The good food sources would be whole-grain bread, cereals, nuts and legumes," Song said. "Although we didn't look at soy in our study because its consumption is very low in the United States, there is evidence supporting that soy may be a good protein source for health."