According to Prevention, the five most beneficial vitamins for the skin are vitamins K, C, B3, E and A. These are useful when applied to skin in the form of creams, serums, lotions, moisturizers and sunscreens. In additional to topical skin treatments, Jen Uscher for WebMD explains that a diet rich in vitamins A, C and E helps the body promote healthy skin from the inside out.
As Prevention explains, topical treatments are a necessary balance to healthy dietary habits because the body does not focus vitamin consumption to areas of the skin where help is needed most, such as around the eyes, on the neck, on dry elbows, and on age spots found elsewhere on the body.
Retinoids are a derivative of vitamin A that are clinically proven effective in fighting several signs of aging. Vitamin B3 is commonly listed on skincare ingredient lists as niacinamide, and is used to prevent the formation of skin discoloration and improve the fatty acid barrier for people with dry or sensitive skin.
WebMD recommends fighting the formation of free radicals from within the body by maintaining a diet rich in colorful fruits and vegetables. Foods such as salmon, walnuts and fortified eggs deliver a high dose of omega-3 fatty acids to the skin, which keeps the skin barrier strengthened and fights inflammation.