A combination of healthy activities including exercise, nutritious diet, computer brain games and socializing can improve cognitive performance in people at risk for dementia, according to a large new study.

The study, conducted in five locations across the United States over two years, is the biggest randomized trial to examine whether healthy behaviors protect brain health.

“It confirms that paying attention to things like physical activity and vascular risk factors and diet are all really important ways to maintain brain health,” said Dr. Kristine Yaffe, an expert in cognitive aging at the University of California, San Francisco, who was not involved in the study.

The results were presented on Monday at the Alzheimer’s Association International Conference in Toronto and published in the journal JAMA.

The study involved 2,111 people, ages 60 to 79, from diverse racial and ethnic backgrounds. None were cognitively impaired. All had sedentary lifestyles, suboptimal diets and two other dementia risk factors, such as a family history of cognitive decline and high blood pressure.

Half of the participants followed a structured program. They were prescribed a healthy diet, socially engaging activities and a weekly regimen of eight exercise sessions and three sessions of computerized cognitive training. They attended 38 meetings with facilitators and fellow participants.