As a fitness-minded individual, you know that you need to care for your mental well-being just as much, if not more, as your physique. After all, what’s the point of having a six-pack or having 21-inch pythons if your mind isn’t all there?

One of the best ways to care for both is to eat the right foods — study after study has shown that certain foods can have a profound effect on your mental state, as well as keeping you fit. And one food group that you’ve been told to eat since childhood can do both better than anything else.

Researchers at Tufts University found that older people who ate fewer berries and apples — fruits rich in flavonoids — were more likely to develop Alzheimer’s or related dementia than those who ate plenty of fruit.

The study, published in the American Journal of Clinical Nutrition, studied how fruit intake affected more than 2,800 people over 20 years. In short, people who neglected to eat berries, pears, and drink herbal teas were associated with a four-fold risk of Alzheimer’s compared to those who had plenty of flavonoids.

Participants’ eating habits were evaluated about every four years via self-completed questionnaires, and at the start all were free of any symptoms linked to Alzheimer’s. Those who failed to eat a high intake of flavonoids reported increasing memory loss, and eventually dementia or Alzheimer’s.

A “high intake” of flavonoids was described as 7.5 cups of berries, or eight apples per month.

Still not convinced you should eat fruit? Well, good news: dark chocolate and red wine are also rich in flavonoids.