We all know to shoot for the recommended daily allowance (RDA) of nutrients — popping supplements to meet our quota lest we fall short. Consumer spending on vitamins has doubled in the past 6 years and fortified foods and vitamins are in. But "when it comes to vitamins, more isn't always better," says Madelyn. The hazards of OD-ing are especially acute for fat-soluble vitamins — including vitamins D, E and A and beta-carotene, which don't easily pass from the body. Tread carefully with supplements and know the "ceiling" of safe intake.