What should you eat to retain youthful skin?

If you really are what you eat, what should you eat to retain youthful skin?

"It's the little things that count," says Dr. Lisa Drayer, author of the new book The Beauty Diet (McGrawHill). "I think many of us want a quick fix, a pill that we can pop, instead of making the long-term investment of changing our lifestyle in order to achieve good health and beauty. Eating a healthy diet that is rich in beauty nutrients is essential."

Here are Drayer's top 10 picks.

1 Wild salmon. Loaded with omega-3 fatty acids that keep skin flexible, wild salmon is a rich source of astaxathin, an antioxidant 100 times more potent than vitamin E. It also contains dimethylaminoethanol (DMAE), a neurotransmitter precursor often used in topical preparations for its skin-toning effects.

2 Low-fat yogurt. Rich in protein, bacteria and vitamins, one cup of plain, low-fat yogurt has 450 mg of calcium to build strong bones, teeth and hair.

3 Oysters. Think of oysters as beauty on the half shell. They are an excellent source of zinc, which is key for skin renewal and the production of collagen.

4 Blueberries. Ranked the No. 1 antioxidant out of 40 common plants, blueberries have five different anthocyanins and vitamin C, which increases antioxidant protection to skin, neurons and blood vessels.

5 Kiwifruit. "Vitamin C in kiwifruit is integral for collagen production and maintenance of healthy skin, and research has suggested that high vitamin C intake is associated with fewer wrinkles," says Drayer.

6 Sweet potatoes. Considered the most nutritious vegetable by the Center for Science in the Public Interest due to its proteins, complex carbohydrates and vitamins, the humble orange spud also has beta-carotene, a powerful antioxidant that protects against age-related wrinkles.

7 Spinach. Popeye knew his stuff: Spinach not only has anti-aging and anti-inflammatory alpha-lipoic acid, it's a great source of lutein and zeaxanthin, which are key to eye health.

8 Tomatoes. Cooked with a bit of olive oil, tomatoes are an excellent source of lycopene, "thought to have the highest antioxidant activity of all the carotenoids," says Drayer.

9 Walnuts. Alpha-linolenic, an essential omega-3 fatty acid found in walnuts, keeps skin smooth and combats inflammatory skin diseases.

10 Dark chocolate. High in antioxidants like epicatechin and gallic acid, dark chocolate increases the flow of blood to skin, reduces roughness and protects against sun damage.