There's a lot of evidence showing that fruits and vegetables are beneficial for reducing the risk of stroke," says Willet. For example, in a 20-year study of 832 middle-aged men, the risk of stroke was 22 per cent lower for every three servings of fruits and vegetables the men ate each day. Again, no one's sure if it's the potassium, magnesium, fibre or other components of fruits and vegetables that prevent arteries from clogging in the brain.