Adults between 19 and 50 should aim to get 1.4 milligrams of vitamin B6 from baked potatoes, bananas, and chickpeas daily. After age 50, men should aim for 1.5 milligrams, while females should get 1.5 milligrams. Some use it to prevent mental decline and lower levels of homocysteine (an amino acid associated with heart disease), but the studies are mixed. Two studies failed to show cognitive benefits, and while B6 does reduce homocysteine, it’s not clear whether this prevents heart attacks.
Bottom line: Take it only if your doctor recommends it.
Vitamin B12-rich foods include fish and shellfish, lean beef, and fortified breakfast cereal; it’s a vitamin vegetarians and vegans tend to be low in. Aim to get 2.4 micrograms from those sources every day. Vitamin B12 deficiency, which can cause anemia and dementia, is a problem for some seniors, so supplements can help. However, high doses of B12 have not been proven to prevent cognitive loss, and they don’t boost energy.
Bottom line: Only take it if your doctor recommends it. These are the 14 vitamin brands doctors trust the most.
Vitamin C can be found in citrus fruits, melons, and tomatoes; adult males should get 90 milligrams a day, while women should aim for 75 milligrams. Some people take it to protect against the common cold, but a review of 30 clinical trials found no evidence that vitamin C prevents colds. There are some exceptions though: It may reduce the risk in people who live in cold climates or experience extreme physical stress, such as running marathons. Smokers may need extra vitamin C. Studies haven’t backed up claims that high doses of vitamin C can fight cancer and heart disease.
Bottom line: Most people don’t need C supplements.
Vitamin E—found in vegetable oil, nuts, and leafy green vegetables—has been thought to prevent heart disease, cancer, and Alzheimer’s disease. Try to get 15 milligrams a day from food. Not only have studies failed to show that vitamin E supplements prevent heart attacks or cancer, but high doses may increase the risk of strokes. One study found that vitamin E from food—but not supplements—helps prevent Alzheimer’s disease.
Bottom line: Don’t take it. Make sure you know the silent signs you aren’t getting enough vitamins.