Consuming enough protein is crucial for women's health over time, and a new study suggests that a specific source of protein is particularly beneficial in preventing many chronic diseases.
Diet plays a pivotal role in maintaining good health as we age, especially adequate protein intake, deemed essential for sustaining major body functions, including muscle mass and function to delay frailty and dependence.
The choices are vast in this domain, with animal proteins like meat and fish, as well as animal-derived products like dairy and eggs, and plant-based proteins from sources like grains (wheat, rice, quinoa...), legumes (dried beans, chickpeas, lentils...), and nuts (almonds, walnuts...). In a study published in The American Journal of Clinical Nutrition, researchers from the Jean Mayer USDA Human Nutrition Research Center at Tufts University recommend focusing more on the latter category due to the many benefits it offers in terms of chronic disease prevention and healthy aging.
For the study, the scientific team analyzed self-reported data from over 48,000 women participating in the Harvard-based Nurses' Health Study, which tracked health professionals from 1984 to 2016.
The goal was to analyze the participants' dietary questionnaires to extrapolate the amount of protein they consumed before comparing these results with their overall health status. The researchers then compared the diet of women who did not develop 11 chronic diseases or lose much physical or mental function with those who did.
The findings revealed a significant decrease in the risk of heart disease, cancer, diabetes, cognitive and mental health decline among participants who included more plant-based proteins in their diet. Specifically, women who consumed more from their forties had a 46% higher chance of remaining healthy into old age.
The beneficial effects of a plant-based diet on cholesterol
Conversely, women who consumed more protein in the form of animal sources such as meats, dairy, and eggs were 6% less likely to remain healthy but were still healthier than women who consumed less protein overall.
"Protein consumption in your forties was linked to promoting good health in older adults," says Andres Ardisson Korat, the study's lead author.
"We also found that the source of protein is important. Getting most of your protein from plant sources in your forties, along with a small amount of animal protein, seems conducive to good health and survival into advanced age. Women who consumed larger amounts of animal protein tended to suffer more from chronic diseases and did not achieve the improvement in physical functions we normally associate with protein consumption."
The greatest beneficial effect observed in women on a diet rich in plant-based proteins was heart disease, simply because their regular consumption was accompanied by a lower LDL cholesterol level.
This "bad" cholesterol can form plaques and fatty deposits on the artery walls, thus preventing blood from circulating to the heart and brain. However, the researchers concede that the benefits of plant-based proteins might also come from the nutrient richness of the plant foods themselves: they contain fibers, vitamins, minerals, and phyto-micronutrients like polyphenols, beneficial for health.
Hence, they believe further research is needed to confirm what might be the cause of the apparent health improvement linked to the consumption of plant-based proteins, taking care not to limit the demographic data to women of a specific age group and profession.
"Protein intake plays an important role in maintaining a positive state of health in old age," asserts Ardisson Korat. In conclusion, he recommends prioritizing legumes, whole grains, and nuts in daily diets but also reminds of the importance of occasionally consuming animal proteins, especially fish, for their iron and vitamin B12 content.
This observation is shared by INRAE, which states that adding more plant-based proteins (cereals, legumes) to seniors' plates is a way to prevent a decrease in muscle capabilities, known as sarcopenia. With aging, the body's protein synthesis becomes less efficient, which is why it is recommended for older people to increase their protein intake, particularly animal proteins, due to their balanced amino acid profile.
However, achieving this goal is not always easy for this population due to appetite loss, less taste for proteins, frequent chewing problems, or the desire to consume less meat or animal products. In this context, INRAE advocates for more plant-based proteins in seniors' diets, while ensuring the bioavailability of amino acids.
"The number of plant-based protein food products is continually growing on the market, and the use of optimization tools suggests the possibility of creating, by mixing them, plant protein ingredients of very high nutritional quality, ensuring both the coverage of minimum essential amino acid needs and an additional supply of amino acids specifically adapted to the senior consumer population," he concludes. According to his recommendation, the recommended protein intake has been set to a minimum of 1g/kg/day for the elderly, knowing that it is 0.83g/kg/day for young, healthy adults.
