Vitamin E is considered to be the most important antioxidant as it prevents enzymes from getting damaged & protects cell membranes of the skin. Studies show that free radicals damage the skin. Vitamin E inactivates them & thus protects the skin from possible harm. Regular application of vitamin E protects the skin from getting dnmaged due to sun exposure. It also minimizes the production of cancer-causing cells in the skin. Wrinkles can be prevented, photo-damage can be avoided & your skin texture can be improved by taking 400 mg of vitamin E everyday. Vitamin E is naturally found in oats, grains, nuts, dairy products & sunflower oil.
Another important antioxidant is vitamin C which is commonly found in the skin. It prevents the free radicals from becoming cancerous or from accelerating the aging process by repairing them. It is found in citrus fruits & vegetables.
Vitamin A or retinoid prevent the skin from drying & becoming flaky or scaly. It aids in the increased production of skin collagen & facilitates skin renewal. It also helps in reducing wrinkle & fine lines. It is found in carrots, broccoli, whole milk dairy, organ meats & eggs. You can supplement your dietary intake of vitamin C externally if you are deficient in vitamin C. avoid its mega doses as it can prove dangerous for your health.
source: http://www.dailyglow.com/askquestion/vitamins-for-aging-skin-what-are-the-vitamins-for-.html