Illustration by Lauren Tamaki

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Fish

The Mediterranean diet can include a whopping six servings of fish a week, but if that's too much for you, don't stress: The scientists behind the MIND diet found that eating fish even once a week can help lower the risk of Alzheimer's. And according to a recent study in the American Journal of Preventive Medicine, consuming baked or broiled fish at least once a week may increase gray matter, a type of brain tissue that diminishes with the disease.