Well, three apples actually - or, two 8oz glasses of apple juice. Those are the equivalent amounts that humans would need to consume to match the amounts given to laboratory animals in a study that seems to indicate that consuming apples can improve memory.

Antioxidants in apples may help slow the decline of the neurotransmitter, acetylcholine, in the brain. Studies have shown that increasing the amount of acetylcholine in the brain can slow the mental decline of people suffering from Alzheimer’s.

Previous studies have shown that foods rich in antioxidants can slow brain-aging and boost memory.