Apr 26, 2011 4:53 PM
By now, it's common knowledge that certain nutrients help specific body parts work better. Healthy bones require calcium and vitamin D. Our hearts may do better when we eat fish rich in omega-3 fatty acids. And for healthy skin we should eat, well, hmmm, that's a good question.
If you're not sure which foods are good for your skin and which ones are harmful, you're certainly not alone. Little research has shown a connection between particular foods and skin health, says Cheryl Karcher, MD, a New York dermatologist who worked as a nutritionist before she became a doctor. And a lot of the "common knowledge" that people pass around about eating and skin health is based on individual people's cases, she says.
Still, "the skin is a reflection of your total body health," says Karcher, who is a spokeswoman for the American Academy of Dermatology. A nutritious diet that keeps your inside healthy will help keep your outward appearance looking good. On the other hand, a poor diet will show up on your skin.
Several experts whose expertise straddles both nutrition and dermatology are here to tell you which foods may support smooth, healthy skin, and which foods are more likely to lead to rashes, blemishes, and breakouts.
For the first part of her career, Valori Treloar, MD, worked with patients like a typical skin doctor. But over time, she grew tired of the few options that she could use on hard-to-treat cases, as well as the serious side effects that some could cause.
So the Massachusetts doctor became a certified nutrition specialist and now promotes diet fixes to her patients along with medicine.
Several studies from 40 years ago "proved" that diet doesn't cause acne, Treloar says, and this thinking became a widely held belief in medicine. "All through medical school and through my dermatology training, I was taught, 'Don't worry about what your patient eats, it's not relevant to their acne,'" Treloar tells WebMD.
But in recent years, some research has supported new thinking.
A good way to improve the health of your skin is to eat in a manner that keeps your blood sugar steady, she tells WebMD. Some foods make your blood sugar quickly soar. This triggers your body to make a burst of the hormone insulin to help your cells absorb the sugar.
If throughout the day you're "eating a cookie, you're eating a granola bar, and you're drinking a sweetened beverage, you're pushing your blood sugar up high and fast, and you're going to have more insulin circulating in your bloodstream," says Treloar, who co-authored The Clear Skin Diet.
Some research suggests that insulin may play a role in acne. In a 2007 study, researchers explored a possible link. The study included 43 teenage boys and young men with acne. For three months, some ate a diet including foods with a low glycemic load (which is a measure of how foods affect people's blood sugar), and others ate a carbohydrate-heavy diet without being concerned about their glycemic index. Those who ate the special low glycemic load diet had more improvement in their acne.
On the other hand, a study published in a dermatology journal later that year didn't find an association between acne, insulin levels, and measurements of glycemic load. So the matter isn't settled yet.
Steps that keep your blood sugar steady, as well as fight inflammation and oxidative damage that could be linked to skin problems, include:
There's no definite link between dairy and acne, but there are theories about it.
In an article he wrote for a medical journal in 2008, F. William Danby, MD, a skin expert who promotes the possible dairy-acne connection, explained how the two may be related. Milk contains components related to the hormone testosterone that may stimulate oil glands in the skin, setting the stage for acne.
Karcher has heard similar stories. "I've had patients who said they stopped dairy and their acne got better. You can have a totally healthy diet without dairy. If a patient feels that is a possible problem, there's nothing wrong with trying it as long as they're followed by someone to make sure they're getting a balanced diet."
"In my skin-care practice, I'd often take people off all dairy products, which is kind of unheard of for RDs to do, but it made a huge difference," says Carmina McGee, MS, RD, a dietitian in Ventura, Calif., who has a special interest in skin disorders.
Although studies have shown associations between dairy and acne, they don't show cause and effect, and they don't prove that dairy causes acne. Anecdotes from people who've quit dairy also don't mean that the same will be true for you.
Dairy is an important source of calcium and vitamin D, which your bones (and the rest of your body) need. So if you cut back, do so with care:
Different fatty acids in the foods we eat can support inflammation or dampen it. And too much inflammation inside your body can show up on your skin, Treloar says. Ages ago, omega-6 fatty acids and omega-3s were evenly represented in the human diet. But we tend to get a lot more omega-6s now.
You can address this imbalance, Treloar says, by:
People with a condition called celiac disease must avoid a protein called gluten, which is found in certain grains. In these cases, eating gluten causes damage in the small intestine.
Concern about gluten's effects in people without celiac disease has become trendy in recent years, McGee says. But people can be sensitive to gluten even if they don't have celiac disease. In some cases, this gluten sensitivity can cause a skin rash, she tells WebMD. However, the rash related to gluten sensitivity, called dermatitis herpetiformis, is seen mainly in people with celiac disease.
A low-gluten diet can make a lot of nutritious foods - such as whole-wheat bread - disappear from your plate. If you start a trial period without gluten, be sure to talk with your doctor first.