"I eat so well all day, so why does my eating seem to get out of control at night?"

Could healthy eating protect your skin from sunburn, wrinkles and even skin cancer? Some studies now suggest that diet may play a role in reducing damage that accumulates from minor sun exposure. But experts emphasize that this can't replace strategies like using sunscreen and protective clothing, and avoiding sun exposure during peak hours.

Researchers say premature aging of skin and skin cancer seem to involve sun damage from ultraviolet light, which creates highly reactive substances, called "free radicals," that damage cell proteins and DNA. Theoretically, antioxidants like beta-carotene and other carotenoids can stabilize free radicals and end the damaging chain reactions they start. A study in the American Journal of Clinical Nutrition noted that carotenoid supplements reduced skin reddening in response to ultraviolet light. The supplements raised carotenoid levels in the skin. A later report in the Journal of Nutrition said people who had higher skin carotenoid levels without supplements suffered less reddening skin damage from ultraviolet light.

These studies involved fair-skinned people with a tendency to develop sunburn. It is not clear if the results would be the same for people with darker skin. The reduced skin damage linked to carotenoids is clearly related to increased carotenoid pigment in the skin. In fact, subjects in the above study who used supplement-level doses developed a slight yellowing of the skin, especially on the face and palms.

Another study, in the Journal of Nutrition, found that tomato paste, which is high in the carotenoid lycopene, also seems to offer some protection from sunlight's damage. After ten weeks, people who ate the equivalent of half a small can of tomato paste each day reduced their usual reddening from ultraviolet light by 35 percent. This study did not evaluate whether skin pigment levels changed, or what mechanisms were involved.

Other research has taken a broader look at how diet might protect skin against sun damage. Many phytochemicals - substances that naturally occur in fruits, vegetables, grains and other plant foods - are antioxidants. A study in the Journal of the American College of Nutrition showed that skin wrinkling on sun-exposed body parts in elderly people was lowest among those who ate the most vegetables, beans and olive oil. Prunes, apples and tea (also high in antioxidant phytochemicals) were also related to reduced wrinkling.

Sunlight exposure reportedly causes 80 to 90 percent of skin cancer, which is why experts recommend sunscreens with a Sun Protection Factor (SPF) of 15 as a minimum. Researchers in the carotenoid and lycopene studies estimate an effect equal to only a 2 or 3 SPF. Furthermore, a panel of experts found that sunscreens probably reduce the risk of some skin cancers but should be only one part of an overall strategy that includes limited sun exposure. Studies suggest that, if using sunscreens leads people to spend more time in the sun, the risk of a very serious skin cancer called melanoma may actually increase.

The American Institute for Cancer Research (AICR) recommends a mostly plant-based diet with five to ten daily servings of a variety of fruits and vegetables to lower overall cancer risk. If such a diet helps protect against sunburn, wrinkling and skin cancer, consider it a bonus. Healthy eating, offering a daily SPF of 2 or 3, may reduce sun damage that occurs during brief periods out of doors. But a truly effective strategy includes sunscreens with SPF of 15 or more, protective clothing and limited sun exposure.