potential of select individual vitamins to prevent or treat any kind of disease. b-12, you hear about b vitamins marketed as energy boosters. it is true your body s -- needs b vitamins to extract energy from food watch is not as clear if you don't have a deficiency adding extra is going to do anything for. studies haven't been able to show it does. strict vegetarians and older adults, the ability of the body to absorb it in the stomach does decrease for some people with age. other than that, most people don't need it. >> arthel: you brought vitamin c, you take that if you have a cold, right? >> there's some good evidence it might help shorten the duration of a geld if you have already one. 200 miligrams a day that's it. mega doses have not been shown to do anything.