"Lather, rinse, repeat" may be standard advice, but shampoo and conditioner alone won't give you the healthy hair you crave. For the most luxurious locks possible, you'll need to step out of the shower, and into the kitchen.
"Your hair grows about 1/4 to 1/2 inch every month, and the foundation of all of our new hair, skin, and nail growth is the nutrients we eat," says Dawn Jackson Blatner, RD, a Chicago-based dietitian. "If you eat a healthy diet, you will grow stronger and healthier cells throughout your entire body -- inside and out."
If you were born with fine, thin hair, you'll never have rope-thick tresses -- no matter what you eat -- but a well-balanced diet that includes plenty of growth-promoting protein and iron can make a difference, say nutrition and hair experts.
And beware of dietary supplements often marketed to thicken hair or make it grow faster. They may backfire.
"Even though you can find beauty supplements on the shelves of most stores, try to get the nutrients you need from foods whenever possible," Paradi Mirmirani, MD, a dermatologist in Vallejo, Calif., tells WebMD. "In rare instances, excess supplementation of certain nutrients, such as vitamin A, has been linked to hair loss."
Read on for the 10 top foods that should be the foundation of your healthy hair diet.
Healthy Hair Food No. 1: Salmon
When it comes to foods that pack a beauty punch, it's hard to beat salmon. Loaded with omega-3 fatty acids, this high-quality protein source is also filled with vitamin B-12 and iron.
"Essential omega-3 fatty acids are needed to support scalp health," says Andrea Giancoli, MPH, RD, a dietitian in Los Angeles and a spokeswoman for the American Dietetic Association. "A deficiency can result in a dry scalp and thus hair, giving it a dull look."
Vegetarian? Include one or two tablespoons of ground flaxseed in your daily diet for some plant-based omega-3 fats.
Healthy Hair Food No. 2: Dark Green Vegetables
Popeye the Sailor Man didn't eat all that spinach for healthy hair, but he could have. Spinach, like broccoli and Swiss chard, is an excellent source of vitamins A and C, which your body needs to produce sebum. The oily substance, secreted by your hair follicles, is the body's natural hair conditioner.
Dark green vegetables also provide iron and calcium.
Healthy Hair Food No. 3: Beans
Beans, beans, they're good for your ... hair?
Yes, it's true. Legumes like kidney beans and lentils should be an important part of your hair-care diet. Not only do they provide plentiful protein to promote hair growth, but ample iron, zinc, and biotin. While rare, biotin deficiencies can result in brittle hair.
Blatner, who is also a spokeswoman for the American Dietetic Association, recommends three or more cups of lentils or beans each week.
Healthy Hair Food No. 4: Nuts
Do you go nuts for thick, shiny hair? You should.
Brazil nuts are one of nature's best sources of selenium, an important mineral for the health of your scalp.
Walnuts contain alpha-linolenic acid, an omega-3 fatty acid that may help condition your hair. They are also a terrific source of zinc, as are cashews, pecans, and almonds. A zinc deficiency can lead to hair shedding, so make sure nuts are a regular on your healthy hair menu.
Healthy Hair Food No. 5: Poultry
Chickens and turkeys may have feathers, but the high-quality protein they provide will help give you the healthy hair you crave.
"Without adequate protein or with low-quality protein, one can experience weak brittle hair, while a profound protein deficiency can result in loss of hair color," Giancoli tells WebMD.
Poultry also provides iron with a high degree of bioavailability, meaning your body can easily reap its benefits.
Healthy Hair Food No. 6: Eggs
When it comes to healthy hair, it doesn't matter whether you like your eggs scrambled, fried, or over easy. However they're served up, eggs are one of the best protein sources you can find.
They also contain biotin and vitamin B-12, which are important beauty nutrients.
Healthy Hair Food No. 7: Whole Grains
Sink your teeth into hearty whole grains, including whole-wheat bread and fortified whole-grain breakfast cereals, for a hair-healthy dose of zinc, iron, and B vitamins.
A whole-grain snack can also be a great go-to food when your energy is zapped halfway through the afternoon, and you've still got hours to go before dinner.
Healthy Hair Food No. 8: Oysters
Oysters may be better known for their reputation as an aphrodisiac, but they can also lead to healthy hair -- and who doesn't love that?
The key to their love and hair-boosting abilities is zinc -- a powerful antioxidant.
If oysters don't make a regular appearance on your dinner plate, don't despair. In addition to getting it from whole grains and nuts, you can also get zinc from beef and lamb.
Healthy Hair Food No. 9: Low-Fat Dairy Products
Low-fat dairy products like skim milk and yogurt are great sources of calcium, an important mineral for hair growth. They also contain whey and casein, two high-quality protein sources.
For some healthy hair foods "to-go," try throwing a yogurt or cottage cheese cup in your bag when you head out in the morning to snack on later in the day. You can even boost their hair benefits by stirring in a couple of tablespoons of ground flaxseeds or walnuts for omega-3 fatty acids and zinc.
Healthy Hair Food No. 10: Carrots
Carrots are an excellent source of vitamin A, which promotes a healthy scalp along with good vision.
Since a healthy scalp is essential for a shiny, well-conditioned head of hair, you'd be wise to include carrots in your diet as snacks or toppings on your salad.
The Big Picture: A Balanced Diet for Healthy Hair
When it comes to foods for healthy hair and beauty, variety is the best way to go.
"An overall balanced diet of lean proteins, fruits, and vegetables, whole grains, legumes, fatty fish like salmon and low-fat dairy will help keep hair healthy," Giancoli says.
If you're tempted to drop pounds fast with the latest fad diet, it could leave you with less-than-healthy hair -- along with a growling stomach. Low-calorie diets are often low in some of the most important nutrients for healthy hair, including omega-3 fatty acids, zinc, and vitamin A. In addition to stunting hair growth and leading to dullness, super-low calorie plans may even cause hair loss.
"Crash diets can affect the hair cycle," Mirmirani tells WebMD. "Losing a significant amount of weight in a short amount of time can affect that normal hair rhythm. Two to three months later, you might notice a significant increase in shedding. This is a temporary problem that you recover from with a well-rounded diet."