Nuts to you: Plant-based diets may support women’s continued health

Although eating enough protein has always been crucial for preserving older persons’ health, not many epidemiologic studies have looked at midlife protein intake and healthy aging.

More than 48,000 US women who self-reportedly ate more plant-based protein had lower rates of chronic diseases and overall better health later in life. Researchers at Tufts University’s Human Nutrition Research Center on Aging have found that as people age, they are more likely to be generally healthy and to develop fewer chronic diseases.

Although eating enough protein has always been crucial for preserving older persons’ health, not many epidemiologic studies have looked at midlife protein intake and healthy aging.

The study, “Dietary protein intake in midlife in relation to healthy aging – results from the prospective Nurses’ Health Study [NHS] cohort,” was recently published in The American Journal of Clinical Nutrition. It found that individuals who consumed higher amounts of protein from foods like fruits, vegetables, bread, beans, legumes, and pasta had significantly lower rates of heart disease, cancer, and diabetes as well as declines in their mental and cognitive health.

3,721 (7.6%) NHS participants in total fit the criterion of healthy aging provided by the team. Consuming protein was strongly linked to a higher chance of aging healthily.

“Consuming protein in midlife was linked to promoting good health in older adulthood,” stated Andres Ardisson Korat, the principal investigator of the study. Additionally, we discovered that protein supply matters. It appears that consuming mostly plant-based protein in midlife, together with a moderate quantity of animal protein, is beneficial for maintaining excellent health and longevity.

The groundbreaking Harvard-based Nurses’ Health Study, which tracked female healthcare workers from 1984 to 2016, provided the findings. The women were judged to be in good physical and mental health at the beginning of the study, and they ranged in age from 38 to 59 in 1984.

In order to identify dietary protein and its implications on healthy aging, a meta-analysis of hundreds of surveys on the frequency of consumption of specific meals was conducted every four years between 1984 and 2016. Using the Harvard University Food Composition Database, they totaled the amount of protein in all the food items and used this information to calculate their protein consumption. They did this by multiplying the number of times each food item was ingested by its protein content.

The researchers next contrasted the diets of women who had 11 chronic diseases and lost a significant amount of physical or mental function with those of those who did. A study conducted in 1984 found that women who consumed higher amounts of plant-based protein—which was then classified as protein from bread, vegetables, fruits, cereal, baked goods, mashed potatoes, nuts, beans, peanut butter, and pasta—had a 46% higher chance of being healthy into old age. Conversely, those who consumed higher amounts of animal protein—found in foods like cheese, milk, fish, and poultry—had a 6% lower chance of maintaining their health as they grew older.

“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,” said Ardisson Korat.

Plant protein showed a greater, more consistent correlation across all observed models and was more closely associated with sound mental health in later life, while animal protein was moderately associated with fewer physical limitations in older age. Higher consumption of plant protein was associated with lower levels of LDL (“bad”) cholesterol, blood pressure, and insulin sensitivity, whereas higher consumption of animal protein was associated with higher levels along with an increase in insulin-like growth factor, which has been linked to multiple cancers. This is especially true for heart disease.

Dairy protein by itself—primarily found in milk, cheese, pizza, yogurt, and ice cream—was not substantially linked to improved health in later life.

The group agreed that, in comparison to animal foods, plants contain a higher proportion of dietary fiber, micronutrients, and healthful compounds called polyphenols, rather than just protein. As a result, the benefits of plant protein may come from components in plant-based food rather than the protein itself.

According to the team’s current research, women should acquire the majority of their protein from fruits, vegetables, nuts, and seeds, but they should also eat some fish and animal protein because these sources are higher in iron and vitamin B12.