Researchers looked at the health records of nearly 3,000 men and women ages 19 to 72, as well as food questionnaires that the participants filled out. The researchers estimated the participants’ total protein intake as well as their dietary percentages of protein from specific sources, such as fast food, full-fat or low-fat dairy, red meat, fish, chicken, and legumes. They also looked at participants’ lean muscle mass, bone mineral density, and quadriceps strength—all measures that are important for fitness, health, and better functioning, especially as we get older.
When the researchers compared this data, they found that people who consumed the least amount of protein overall also had the lowest measures of muscle mass and strength. But the type of protein people ate didn’t seem to matter: After the researchers adjusted for other factors, they found the differences in protein sources had no impacts on musculoskeletal health, for men or for women.
Lead author Kelsey Mangano, PhD, assistant professor of nutritional sciences at the University of Massachusetts Lowell, says the study delivers a message that meat and veggie lovers can both celebrate: “As long as a person is exceeding the recommended daily allowance for protein, no matter the source in their diet, plant or meat protein,
The study was observational in nature, so it was unable to draw any cause-and-effect conclusions—and since the participants’ age range was so broad, the findings should be replicated in older adults who tend to get less protein on a daily basis, says Mangano. (For people who don't consume enough protein, she speculates, the type they eat may become more important.)
It's also important to remember that the study only looked at bone and muscle health—just two components of good health overall. “When we think about our health as a whole it is important to decrease intakes of saturated fat, sodium, and added sugars,” says Mangano, who is also a registered dietitian.
“Therefore, people should choose their protein sources keeping overall dietary recommendations in mind,” she continues. “Choose protein sources that are lean—limiting saturated fat—and also those that are low in sodium.” That means avoiding processed meats like bacon, for example.
When it comes to other benefits—like, say, living longer or losing weight—some studies have suggested that plant-based protein may have a bit of an edge. But when looking at the research as a whole, says Mangano, “there is no clear evidence whether animal or vegetable sources may be more beneficial for overall health.”
More studies on https://academic.oup.com/ajcn.