Loaded with lycopene, cooked tomatoes (in juice or sauce) can protect skin against sunburn. Try to consume about one cup a week, paired with a healthy fat (like olive oil or avocado), which will help your body absorb the lycopene.
2. Nuts and Fish
"Research suggests that their high concentrations of omega-3 fatty acids can hydrate the skin and lessen the appearance of deep wrinkles," says nutritionist Dawn Jackson Blatner, who recommends eating 12 ounces of fish (such as salmon or cod) every week, or 1 ounce of walnuts a day. You should notice a change in your skin in about six weeks.
3. Kiwis, Blueberries, Sweet Potatoes
These are just a few of the brightly colored foods that are rich in antioxidant vitamins C and E; when taken orally, they can help protect against UV damage. A study published last year found that a diet high in vitamin C was associated with less skin dryness and wrinkling. Blatner recommends eating 2.5 cups of fruit and 2 cups of vegetables every day.
4. Red Meat, White Kidney Beans, Yogurt, and Oysters
They're all high in zinc, which is essential for collagen formation. You need, for example, three ounces of beef, one cup of yogurt, and half a cup of white kidney beans, or just one incredibly zinc-heavy oyster, daily, says nutritionist Lisa Drayer, author of The Beauty Diet.
5. Green Leafy Vegetables, Such as Spinach and Swiss Chard
A recent study found that people with a history of squamous cell carcinoma who ate about two servings of these greens weekly reduced their risk of subsequent skin cancers. Researchers credit the vegetables' high concentration of the organic pigments lutein and zeaxanthin. They also contain vitamin K, which has been shown to strengthen blood vessels and may help prevent varicose veins.
6. Dark Chocolate
Its high flavonol content can minimize skin roughness and has been shown to improve circulation to give skin a healthy glow, says Drayer, who recommends looking for chocolate that is at least 60 percent natural cacao (not "Dutch-processed," which no longer contains its natural flavonols). Treat yourself to an ounce a day.
7. Green Tea
It's one of the most powerful antioxidants around, says Leslie Baumann, MD, director of the Cosmetic Medicine and Research Institute at the University of Miami, who drinks 3 cups a day to fight the free radical damage and inflammation that can contribute to skin aging.
8. Supplements with Substance
While experts agree that a well-rounded diet is the most dependable—not to mention all-around healthiest—route to better skin, there are a number of supplements with good science behind them.
Biotin: Studies have shown that 2.5 milligrams of daily biotin supplements can help strengthen brittle nails, says Noah Scheinfeld, MD, assistant clinical professor of dermatology at Columbia University. (Try Appearex, $32 for a 12-week supply.)
Heliocare: A Harvard study showed that these capsules, which contain a fern-derived antioxidant extract, help to prevent sunburn and collagen damage. Take two capsules one hour before prolonged sun exposure ($63 for 60 capsules).
Omega-3 fatty acids: If you don't think you're managing to get enough of these proven skin smoothers in your diet, consider fish oil capsules. Baumann recommends 1,000 milligrams of fish oil supplements (like Nordic Naturals Omega-3 Purified Fish Oil, $16 for 60 capsules) daily.