Vitamins B and K are essential to healthy skin. Without vitamin B, the skin can flake off huge chunks of oily dandruff before it breaks open and bleeds. Without vitamin K, bruises can form where the skin has not even been touched, such as the dreaded raccoon eyes that can greet us in the morning.
The good news about these horrible skin vitamin deficiencies, however, is that almost no one ever has them. Even in the modern industrial diet, deficiences of B vitamins are almost unheard of (since so many products are fortified with various forms of vitamin B) and eating even one serving of greens a week can be enough to circumvent deficiency of vitamin K (although eating greens every day is generally good for health). The skin vitamins that people don't really get, especially if they have acne, are usually A, C, and E.
The prescription drugs Accutane and Retin-A are actually super-potent forms of vitamin A, so potent, in fact, they can cause skin irritation that is worse than the skin conditions they treat. Like its chemical cousins, vitamin A reduces the production of sebum in skin pores and stops the formation of the horn-like keratin protein that can trap sebum inside. Vitamin A, taken in doses of up to 8,000 IU a day, has no side effects.
Vitamin C is the best known of all the natural antioxidants. This vitamin is absolutely essential for the skin to make collagen. As you probably know, collagen is the elastic protein that provides a tough framework for the skin. Without collagen, the skin would literally fall apart.
One of the frequently overlooked benefits of vitamin C is counteracting the effects of eating unhealthy fats. An adequate of supply of vitamin C stops the production of arachidonic acid from fats found in eggs, beef, and lunchmeat. The less arachidonic acid, the less the production of inflammatory chemicals that redden and irritate the skin.
Vitamin E is of tremendous importance to the health of the body in general, but it plays a secondary role in the skin. Vitamin E is a cofactor for vitamin A. Vitamin A cannot stop inflammation of the skin until vitamin E levels are adequate. Taking vitamin E complements vitamin A, and vitamin E supplements can be useful even if you get all your vitamin A from your diet.