Intake of protein, especially from plants, in middle age is associated with higher odds of healthy aging and positive mental and physical health status in older women, a recent analysis of the Nurses’ Health Study (NHS) data suggests.
The study is said to be the first to examine the long-term impact of midlife protein consumption on later health status.
Dr. Andres V. Ardisson Korat
Writing in the American Journal of Clinical Nutrition, a team led by Andres V. Ardisson Korat, DSc, a nutritional epidemiologist at the USDA Human Nutrition Research Center on Aging at Tufts University in Boston, Massachusetts, found the following midlife protein–related odds ratios (ORs) for later healthy aging measured at ages 70-93.
For each 3% energy increment from various protein sources:
- 1.05 (95% confidence interval, 1.01-1.10) for total protein
- 1.07 (1.02-1.11) for animal protein
- 1.14 (1.06-1.23) for dairy protein
- 1.38 (1.24-1.54) for plant protein
In substitution analyses, significant positive associations were observed for the isocaloric replacement of animal or dairy protein, carbohydrate, or fat with plant protein — with increased ORs for healthy aging of 1.22-1.58 for each 3% of energy replacement.
On the measure of physical function, for example, replacing calories from all macronutrient variables with equivalent calories from plant protein was associated with 20%-60% higher odds of having no physical function limitations. Plant protein was also associated with higher odds for good mental status.
“Other studies have looked at protein intake in older adults, but we felt midlife was a more relevant etiological window,” Dr. Ardisson Korat said in an interview. “Our findings generally align, however, with those of protein intake in older populations, which have shown that protein can reduce the risk of frailty.”
He added that the benefits of protein, especially from plant sources, would likely apply to men as well and increasing plant protein intake is not difficult. “If you want a snack during the day, eat a handful of nuts instead of potato chips,” he advised. And eating several meals a week featuring beans, peas, lentils, tofu, whole grains, or seeds is an easy way to boost dietary plant protein, which comes with health-promoting soluble and insoluble fiber as well as antioxidant and anti-inflammatory polyphenols and other phytochemicals.
Conversely, plant but not animal protein consumption in older adulthood was linked to a lower risk of frailty in a previous NHS trial.
Higher plant protein intake was associated with a better probability of achieving healthy aging defined by changes in functional impairments, self-reported health/vitality, mental health, and use of health services in the Spanish Seniors-Estudio Sobre Nutricion y Riesgo Cardiovascular.
In contrast, animal protein intake in middle adulthood has been linked to an increased risk of premature death from chronic diseases driven by cardiovascular disease mortality.
The present findings are consistent with those observed for protein intakes in older adulthood, Dr. Ardisson Korat said.
Dr. Douglas R. Dirschl
“This study underscores the health advantages for midlife adults consuming adequate dietary protein — particularly plant protein — as one component of pursuing a healthy lifestyle,” said Douglas R. Dirschl, MD, chair of orthopedic surgery at Baylor College of Medicine in Houston, Texas. Most Americans consume adequate amounts of protein, but according to Dr. Dirschl, who treats many older patients for osteoporotic fractures and other musculoskeletal conditions, many US diets are subpar in this nutrient.
While protein is essential for bone and muscle formation and maintenance, “a surprising number of Americans are protein deficient, even those who seem hale and are overweight,” he said.