12 Foods for Stronger Nails and Thicker Hair

Beer is one of the richest sources of silicon in the average diet, says research from the Journal of the Science of Food and Agriculture. "Silicon is a trace mineral thought to increase circulation to the scalp, which is good news for hair growth," says Rebecca Kazin, MD, dermatologist at the Washington Institute of Dermatologic Laser Surgery and the Johns Hopkins Department of Dermatology. That explains why a daily 10-milligram silicon supplement was shown to reduce hair and nail brittleness after 20 weeks, according to the Archives of Dermatological Research. No need to go overboard, though: Most single servings of beer contain more than 10 milligrams of silicon. Experts recommend that having no more than one drink a day if you're a woman, and two if you're a man.

More research still needs to be done, but some studies suggest a link between vitamin D and hair loss. Example: Women with hair shedding had lower vitamin D levels than women with healthy hair, according to a Skin Pharmacology Physiology study. Plus, Koff says calcium is a key mineral in building healthy hair and nails (note: you need vitamin D to absorb calcium). Of course, vitamin-D fortified milk offers both, but speak to your doctor about a vitamin D supplement if you think you might be deficient.

Rats deficient in selenium (a trace element linked to protection against oxidative stress) have sparse hair growth, says a study in PLoS One. Just six to eight Brazil nuts meet almost 800% of your recommended daily value, according to the National Institutes of Health.

To keep your strands strong and luscious, snack on some walnuts. They are chock-full of two secret ingredients for gorgeous locks: omega-3s (which keep your hair hydrated) and vitamin E (which repair damaged follicles. Plus, walnuts also contain copper, which studies have shown may keep your natural color rich and stave or premature grayness.