B Vitamins
When it comes to brain health, focus on the three B’s: vitamins B6, B12, and B9 (folate). “These three types of B vitamins are necessary for the brain’s normal functioning,” says Dr. Agarwal, “and any deficiency in them may increase the risk of memory loss and other forms of cognitive decline.”
The reason: These vitamins help boost the production of neurotransmitters, or brain chemicals, that deliver messages between the brain and body.
Increasing your B12 by taking a supplement may also be helpful with memory loss as you age because it’s a very common nutrient for older people to develop a deficiency in, notes Díaz-Santos.
Where to find them: Beans are one of the best sources of B vitamins across the board. You can find B6 in bananas, oranges, papaya, cantaloupe, tuna, salmon, poultry, and dark leafy greens. Folate is found in broccoli, greens, whole grains, eggs, peanuts, and sunflower seeds.
Vitamin B12 is found solely in meat and fish products; for vegans and vegetarians, nutritional yeast and fortified whole grains are a good way to get your supply. People on a plant-based diet do have a much higher risk of a true B12 deficiency, so talk to your doctor or dietitian about whether or not a B12 supplement is right for you.
Vitamin C
This antioxidant is known for its immunity powers, but vitamin C and other flavonoids also support the brain, potentially by taming brain-damaging inflammation.
In one study, by Rush University researchers including Dr. Agarwal, people who consumed vitamin C-rich strawberries at least once a week were less likely to develop Alzheimer’s over the course of the nearly 20-year study period.
Where to find it: Get vitamin C in abundance from kiwi, red and green bell peppers, citrus, berries, broccoli, cauliflower, brussels sprouts, and tomatoes.