“It’s a bigger effect, because each of the behaviors is independent and each is contributing something (unique),” said Dr. Nikolaos Scarmeas, an (associate) professor of neurology at Columbia University Medical Center and the first (author) of the paper, published in The Journal of the American Medical Association. Diet may be (protective) because it can improve (metabolic) factors and reduce cardiovascular risks, inflammation and oxidative stress, he suggested, while physical activity has been associated with (positive) changes in the brain (along) with other positive effects. The (amount) of activity needed to make a difference was not very (substantial); the most active elderly were only getting about four hours of (moderate) activity or 1.3 hours of vigorous activity each week, Dr. Scarmeas said.

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