Vitamin A. If your vitamin A levels are up to snuff from the foods you eat, adding more probably won't do much more for your skin. That said, if those levels drop even a little below normal, you're likely to see some skin-related symptoms, including a dry, flaky complexion. That's because vitamin A is necessary for the maintenance and repair of skin tissue. Without it, you'll notice the difference. Fruits and vegetables are loaded with vitamin A.
Topical vitamin A is the form that makes a real difference in your skin. Medical studies show a reduction in lines and wrinkles, good acne control, and some psoriasis relief, all from using creams containing this nutrient. For example, in research presented at the Annual Meeting of the American Academy of Dermatology in 2003, researchers from France showed that topically applied retinol plus vitamin C demonstrated a "reversal of skin alterations induced by chronologic aging and photoaging."
In another study published in the British Journal of Dermatology, doctors found that foods high in beta-cartotene -- a form of vitamin A -- appeared to reduce the risk of psoriasis.
The prescription treatment for acne called Retin-A is derived from vitamin A. The less potent, over-the-counter formulations are sold as retinols and used as anti-aging treatments.