No vitamin, supplement, food, or drug has been shown to cure Alzheimer's.
One promising antioxidant, resveratrol, is found in red grapes. But resveratrol also could wind up like vitamin E, vitamin C, gingko biloba, B vitamins, and coenzyme Q10. All carried similar hopes at one time or another, but none has been proved to prevent or slow Alzheimer's, much less reverse it.
Research suggests your best bet is an antioxidant-rich diet of fruits, vegetables, fish, and nuts to help protect your brain. There’s no silver bullet.