Women who consume higher amounts of protein, especially from plant sources, have fewer chronic diseases and are more likely to be healthier overall as they age, a study led by Tufts University finds.

The research, published in The American Journal of Clinical Nutrition, analyzed data on more than 48,000 women aged 38-59.

The researchers found significantly less heart disease, cancer, diabetes and a decline in cognitive and mental health in women who included more protein in their diet from sources such as fruits, vegetables, bread, legumes and pasta, compared to those who ate less.

Specifically, those who ate more plant protein were 46% more likely to be healthy in the following years. However, women who ate more animal protein were 6% less likely to stay healthy as they aged. Animal protein was marginally associated with fewer physical limitations in older age, but plant protein had a stronger and more consistent association across all observed models and was also more closely associated with good mental health later in life.

“Protein consumption in middle age is associated with promoting good health in old age,” says lead study author and scientist at Tufts University’s Jean Mayer Center for Human Nutrition Research on Aging, Andre Ardison Corat. He adds that “the source of the protein matters. “Getting the majority of protein from plant sources in middle age plus a small amount of animal protein appears to favor good health and survival in older age.”

The researchers acknowledge, of course, that the benefits of plant protein may come from the higher percentage of nutrients in plant foods rather than the protein itself.