Middle-aged women who eat diets rich in plant proteins may be more likely to remain healthy as they age compared with their counterparts who consume a lot of meat, a new study suggests.
For the study, launched in the 1980s, researchers examined data from dietary questionnaires completed by almost 49,000 women who were 49 years old on average. Overall, participants got about 13 percent of their daily calories from animal protein, roughly 2 percent from dairy proteins, and around 5 percent from plant proteins, according to study results published in the American Journal of Clinical Nutrition.
Animal protein came from sources like beef, chicken, seafood, milk, and cheese. Plant protein included sources like bread, vegetables, fruits, pizza, cereal, baked items, mashed potatoes, nuts, beans, peanut butter, and pasta.
At the start of the study, participants were free of 11 common chronic diseases like heart disease, diabetes, and cancer, and they also had no physical or cognitive impairments. After about three decades of follow-up, this was still true for roughly 3,700 women, who researchers called “healthy agers.”
Women who consumed the most plant proteins were 46 percent more likely to be healthy agers, while participants who ate the most animal protein were 6 percent less likely to be healthy agers.
“The advantage of consuming more plant protein compared with other nutrients in the diet is that plant protein is associated with lower risk of cardiovascular disease and other chronic conditions. It promotes good physical function by enhancing muscle synthesis. And it comes from food sources that typically contain high-quality carbohydrates, such as dietary fiber, vitamins and minerals, and antioxidants,” says lead study author Andres Ardisson Korat, ScD, a scientist at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston.
What Are the Healthiest Sources of Plant Protein?
Obviously, nutrition science has advanced since the 1980s. Bread might not be the first thing that comes to mind, for instance, when people think of plant-based protein. But it can indeed contribute to the total amount of protein people consume, says Samantha Heller, RD, a registered dietitian in New York City who wasn’t involved in the new study.
“Proteins in foods such as grains contribute to the overall protein intake for plant-based eating styles,” Heller says. “A cup of cooked pasta contains about 6 to 7 grams of protein. A typical slice of whole-wheat bread contains close to 4 grams of protein.”
For many people, it still makes sense to focus on consuming whole grains instead of options like white bread or white rice, says Michal Melamed, MD, a professor of medicine, pediatrics, and epidemiology and population health at Albert Einstein College of Medicine and Montefiore Medical Center in the Bronx, New York.
“Choosing whole grains is healthier, especially if the person is predisposed to diabetes, because it takes the body longer to digest whole grains so that the release of the sugars takes longer,” says Dr. Melamed, who wasn’t involved in the new study. “I would pick whole-wheat bread, brown rice, and sweet potatoes if possible and if the person has no other dietary restrictions.”
These foods that promote a slower release of sugars are considered low glycemic index foods. Consuming more plant-based proteins that are lower on the glycemic index may ultimately be one key to preventing many common chronic diseases, says David Jenkins, MD, PhD, a professor in nutritional sciences and medicine at the University of Toronto, who wasn’t involved in the new study.
“Many of the plant protein foods are also low glycemic index foods that may be protective for diabetes, total cardiovascular disease, diabetes-related cancers such as breast and colorectal cancer, and all-cause mortality,” Dr. Jenkins says.
You Can Cut Back on Meat Without Eliminating It Entirely
One drawback of the study is that it didn’t examine which specific types of plant-based protein might have the most benefits when it comes to healthy aging, or which sources of animal protein might be particularly harmful. Red and processed meats, in particular, have long been linked to a variety of chronic health issues. Fish, though, especially types high in omega-3 fatty acids, have demonstrated heart-health benefits.
Still, the results add to the evidence that it can be beneficial to have more plant-based meals, Melamed says. The good news is even small changes can help, and you don’t necessarily need to give up meat altogether to see some benefits.
“On the whole, people need to keep in mind that eating animal protein in the long run, is probably not healthy,” Melamed says. But it’s okay to cut back in the way that makes sense to you.
“Sometimes people switch gradually, becoming pescatarian, then vegetarian, then vegan,” Melamed says. “Sometimes people are able to cut out meat altogether but still eat meat on special occasions. There is a wide range of healthy dietary choices that people make.”
