THE HEALTHY HAIR DIET

Products aren't the only thing that matter in the crusade for gorgeous strands.

Want gorgeous, healthy-looking hair, à la Olivia Palermo? Focus on these foods a few times a day and you'll see longer, stronger, shinier hair in no time.

Sea Buckthorn

WHY IT WORKS: It's rich in beta-carotene, vitamin C, and omega 7s. "In Latin, it literally means 'shiny horse'," saysLauren Slayton, RD, founder of Foodtrainers in NYC. "And it's the essential fatty acids that it contains that help to make human hair shiny, too." While it's a common ingredient in skincare, Slayton, says she's a fan of taking it in supplement form daily (a shot glass worth). Try Sibu Beauty Sea Buckthorn Liquid Supplement, $30sibubeauty.com.

Clams and Oysters

WHY THEY WORK: "Zinc is a mineral that is important in the repair—and growth—of tissue, including the growth of hair," explains Deborah Enos, a certified nutritionist in NYC. "If your body is low in zinc, you may experience slow growth of hair and actual hair loss." Some non-seafood options include peanut butter, cheese, nuts, and seeds, she says.

Papaya and Peppers

WHY THEY WORK: "It’s the vitamin C in these two foods that help boost the production of collagen that surrounds hair and keeps it strong," explains Slayton, who recommends working these two vitamin-C rich foods into one to two meals a day (or other kinds if you want, too—i.e. lemons, oranges, and grapefruit). 

Peanuts

WHY THEY WORK: "They're one of the best sources of biotin, a form of vitamin B, which increases hair growth and overall scalp health," says Slayton. "Your body needs biotin to metabolize carbohydrates, fats, and amino acids, the building blocks of protein and because hair is made up of protein, biotin helps hair grow faster." Other biotin-rich foods include eggs and salmon for protein, she says.

Evening Primrose Oil

WHY IT WORKS: "It's one of the top sources of gamma-linolenic acid, an omega-6 essential fatty acid that promotes hair growth," explains Slayton. Try Barleans Organic Oils Evening Primrose Oil, $17.50, vitaminshoppe.com.

Brussels Sprouts

WHY THEY WORK: Again, vitamin C is crucial to growing healthy, pretty hair: "Brussels sprouts are a good source of vitamin C, which is important in keeping your hair vibrant and healthy because it's used by the body to form collagen," says Enos. "Even a mild deficiency of vitamin C can lead to split ends, so make sure to eat foods that have it on a daily basis."

Lentils

WHY THEY WORK: They're a source of protein and also laced with essential minerals iron and zinc. "Zinc regulates hormones that affect hair growth," says Slayton. "And some studies have found a link between iron levels and hair loss in women."

Spinach

WHY IT WORKS: "This vegetable is full of iron and folate, which is a B vitamin that is helpful in the creation of red blood cells," explains Enos. "While iron allows the blood cells to carry oxygen. And the two are a winning combination for your hair and the rest of your body, as well." Also, try adding foods that contain either one of these important hair nutrients, too. For example, asparagus and broccoli are rich in folate; garbanzo beans and Swiss chard are great for iron.

Greek Yogurt

WHY IT WORKS: "It's high in protein and vitamin B5 (aka pantothenic acid), a good combination for helping to increase hair growth," says Enos. (Try Maia Yogurt, $1.50,maiayogurt.com.) It's also a source of vitamin D, which has been recently linked by research for helping to promote healthy hair follicles.