Diets rich in plant protein linked to healthier aging in 32-year study

Study details

The findings were based on an analysis of data collected from 48,762 women who participated in the Nurses’ Health Study between 1984 and 2016. All the women were aged between 38 and 59 at the beginning of the study.

The research was published in the American Journal of Clinical Nutrition in January 2024.

According to the findings, the women in the study who had higher amounts of plant proteins in their diets were less likely to have heart disease, cancer, diabetes, and declines in cognitive health over the 32-year follow-up period.

Though the study relied on self-reported data rather than clinical tracking, the findings were still deemed reliable in providing a perspective on the health advantages of consuming more fruits, vegetables, grains and legumes—and less animal proteins.

“Consuming protein in midlife was linked to promoting good health in older adulthood,” said Andres Ardisson Korat, lead author of the study and scientist at the USDA Human Nutrition Research Center on Aging at Tufts University. “We also found that the source of protein matters.”

Due to its long 32-year data range, the Nurses’ Health Study survey has been used regularly over the years for analyzing differnt aspects of women’s health.

In the current data extraction, researchers reviewed surveys collected every four years on how frequently people ate certain foods to analyze how dietary protein correlated with healthy aging.

The analysis was based on rates of 11 chronic diseases, declines in physical function, and mental health scoring.

Published findings

The researchers extrapolated that the women who ate more plant-based protein were 46% more likely to be healthy into their later years. Those who consumed the highest amounts of beef, chicken, fish and dairy, however, were 6% less likely to stay healthy as they aged.

“Those who consumed greater amounts of animal protein tended to have more chronic disease and didn’t manage to obtain the improved physical function that we normally associate with eating protein,” Korat said.

While debate rages across the U.S. as to whether vegetarian or carnivore diets are healthier, it is important to note the current study was not a vegetarian comparison per se—it was more about which protein source dominates one’s diet.

In fact, the researchers noted that protein consumption tends to decline as people age, and the study found that study subjects receiving adequate protein—from any source—were healthier than those with insufficient intake.

Room for limited animal protein?

Moreover, since a few nutrients are more readily available in animal proteins, the study results appeared to show that acquiring a minimal amount of animal protein was beneficial: “Getting the majority of your protein from plant sources at midlife, plus a small amount of animal protein, seems to be conducive to good health and good survival to older ages,” Korat noted.

An earlier study corroborated this line of thinking: Researchers at Purdue University found protein from “two ounce-equivalents” of animal-based protein foods provided a greater essential amino acids bioavailability than an equal two ounce-equivalents of plant-based protein foods.

These results highlight the need of low-or-no animal food consumers to make sure they eat a wide variety of plant foods. Since plant foods do not contain a complete amino acid profile, a wide variety is needed to guarantee adequate intake of all amino acids.