More Plant Protein in Midlife Linked to 38% Higher Odds of Healthy Ageing: 48,000 Women

It is known that protein is important for maintaining muscle strength and health in old age, but few studies have looked at how protein eaten in midlife connects to ageing patterns decades later. Researchers at the Human Nutrition Research Center on Aging at Tufts University and the Harvard T.H. Chan School of Public Health in the United States examined this question using data from 48,762 women in the Nurses' Health Study.

Methods and Results

For women who were under 60 at enrolment, protein intake was calculated from a validated food frequency questionnaire and divided into total, animal, dairy and plant protein. Healthy ageing was defined as being free of 11 major chronic diseases, having good mental health, and having no cognitive or physical function impairment, and 3,721 women (7.6%) met this definition.

For each additional 3% of energy intake from protein, the odds ratio for healthy ageing was 1.05 for total protein, 1.07 for animal protein, 1.14 for dairy protein and 1.38 for plant protein, so the association was strongest for plant protein. In substitution analyses that replaced the same amount of energy from animal or dairy protein, carbohydrate or fat with plant protein, the odds ratios were also 1.22 to 1.58. Plant protein was also associated with having no physical function limitations and with good mental status.

The participants were limited to women who were nurses, and diet was based on self-reports. Because this is an observational study, it cannot prove a causal link in which protein intake directly leads to healthy ageing.