Eating more plant protein in midlife may help promote healthier aging in women, study says

Our bodies need a certain amount of protein to stay healthy as we age — but not all protein needs to come from meat or dairy. A study published today in The American Journal of Clinical Nutrition revealed that women who eat higher amounts of protein from plant-based sources have fewer chronic diseases and are generally healthier as they get older.

Women whose diets included more high-protein foods, especially planted-based protein, were 46% more likely to remain healthy later in life. However, women who consumed higher levels of animal protein — like beef, chicken, milk, seafood and cheese — were 6% less likely to stay healthier as they aged.

Researchers looked at data from the Nurses’ Health Study, which followed more than 48,000 female health care professionals from 1984 to 2016. The women were between the ages of 38 and 59 in 1984 and were deemed to be in good physical and mental health at the start of the study. The authors recognized that their analysis is subject to several limitations since the study population included mostly white females.

Why this matters

Most people do not consume enough protein, research shows, which can lead to conditions like sarcopenia and increase fracture risk as we age. And it often becomes more difficult to eat a healthy diet in older age, due to issues like food insecurity, changes in the body’s ability to absorb nutrients, or malnutrition.

Even in middle age, eating a protein-healthy diet can be challenging, for reasons such as lower socio-economic status and poor food literacy, among others.

Journalists might want to look into whether local programs are helping to educate communities on food literacy and the importance of consuming more healthy proteins and ask whether physicians are screening their patients for food insecurity or educating them about healthier eating.

Protein type makes a difference

The source of the protein matters, according to lead study author Andres Ardisson Korat, D.Sc., a Tufts University research scientist who focuses on food, nutrition and geriatric syndrome. The analysis clearly showed that eating more plant-based protein in middle age, along with a small amount of animal protein, was associated with both better health and longevity.

These findings seem to support the recommendation that women get most of their protein in the form of fruits, vegetables, nuts and seeds, although they should also consume some fish and animal protein for their iron and vitamin B12 content.

Researchers analyzed self-reported surveys collected every four years for the Nurses’ Health Study on how frequently people ate certain foods to determine dietary protein consumption and potential effects on aging. In 1984, non-animal dietary protein was defined as protein obtained from bread, vegetables, fruits, pizza, cereal, baked items, mashed potatoes, nuts, beans, peanut butter and pasta.

The researchers compared the diets of relatively healthy women with the diets of those who had more health and cognitive issues. Women whose diet included more non-animal protein were nearly twice as likely to remain healthy later in life as those who consumed more animal protein.

Higher levels of plant-based protein were more consistently and strongly correlated with health factors over time, including cognitive health. Higher consumption of plant protein made a noticeable impact on heart disease, including reduced LDL cholesterol, blood pressure and insulin sensitivity. Higher animal protein intake was tied to higher levels of these markers, along with increased insulin-like growth factor, which has been detected in multiple cancers. Dairy protein alone (mainly milk, cheese, pizza, yogurt, and ice cream) was not significantly associated with better health status in older adulthood.

It’s possible that the benefits of plant protein might come from components in plant-based food, rather than the protein. Compared to animal foods, plants contain a higher proportion of dietary fiber, micronutrients, and beneficial compounds called polyphenols, researchers explained.