Diet for healthy skin

"The most important part of the skin barrier is lipids, including phospholipids, free fatty acids, cholesterol, and ceramides," says Amy Newburger, MD, an attending physician in the Dermatology Department at St. Luke's Roosevelt Medical Center. "Skin without enough fat in it has a protein predominance and is kind of like a mess made just of twigs with no glue between them." Water easily escapes through a barrier without lipids, allowing skin to become dehydrated.

Polyunsaturated fatty acids are necessary for the production of intercellular lipids — the "glue" between the "twigs" in the stratum corneum, or surface of the skin. They also have an anti-inflammatory effect on irritated skin. Two types of fatty acids that are "essential" — that is, they must be obtained through the diet — are omega-3s, and omega-6s.

Foods that are high in omega-3 fatty acids include fatty fish like salmon, herring, mackerel, anchovies, and sardines, as well as flaxseed oil, some types of eggs, and grass-fed beef. Evening primrose oil and borage seed oil, which are high in omega-6s, help hydrate the skin and prevent water from evaporating, says Leslie Baumann, director of the University of Miami Cosmetic Medicine and Research Institute. "If you don't like fish or are pregnant and can't eat it, omega-3 supplements are a good option." Most Americans get enough omega-6s through their diet because they're contained in corn and safflower oils.

While anecdotal success of fatty acids for alleviating dry skin has not been conclusively bolstered by research, several studies have shown significant positive effects:  

In a 2006 study of 50 patients with atopic dermatitis, 96 percent of those given capsules of evening primrose oil for five months showed notable reduction in intensity, itching, and dryness of the skin. In another study, of 29 elderly patients, borage seed oil supplements taken in pill form helped reduce water loss from the skin by 10.8 percent. And in a study of 118 infants with high risk of developing atopic dermatitis, those who were given borage seed oil and went on to develop the condition experienced a lower severity of the disorder than those in a placebo group. On the other hand, a 2006 meta-analysis of 22 studies that tested the effects of essential fatty acid supplementation found that no significant benefit was conferred on people with atopic dematitis by plant and fish oil supplements. More studies must be conducted before conclusions can be reached.

Vitamins and Minerals for Dry Skin  

"Vitamin C is necessary for the function of the enzyme that causes collagen to form," says Dr. Newburger, "and collagen acts as a sponge for moisture." Newburger adds that copper and zinc are also necessary. Together, vitamin C, zinc, and copper keep collagen denser, which in turn allows for plump, hydrated skin. "Any good multivitamin with trace minerals in it contains zinc and copper," says Newburger. Zinc has also been found to have anti-inflammatory effects, which is vital for maintaining smooth skin.
Caffeine, Alcohol, and Dry Skin

While consuming caffeine is unlikely to dehydrate you, it does make the blood vessels constrict, which is why it's used in eye creams (to reduce puffiness). "Long term, this means a reduced amount of blood flow and nutrients though the tissues," warns Newburger. "And if you don't have healthy circulation, you won't have age-appropriate cell turnover." In the case of alcohol, Michele Murphy, a registered dietitian at NewYork Presbyterian–Weill Cornell Medical Center, explains that although it's a diuretic, you'd need to be severely dehydrated to experience any noticeable changes. "The average person having a glass of wine with dinner every night and maintaining adequate fluid intake is unlikely to see any real difference," she says. Contrary to popular belief, drinking large amounts of water does not affect skin. "The water we drink that's processed internally isn't going to impact the external look or feel of the skin," Murphy says. Instead, it's the skin's outer layer that is essential for keeping moisture in.
Don't Overdo It
If you're already eating a balanced diet with sufficient fats, adding more fats or taking supplements is not necessarily a quick fix for dry skin. "If you're deficient in fat or certain vitamins, it does have the potential to affect the look or feel of your skin," says Murphy. "But supplementing beyond what the body needs has not been shown to improve skin."