Those sun-worshippers who still haven't accepted the warnings about tanning may want to consider this: sunscreen is probably the best anti-aging regimen available. A new study offers proof that regular sunscreen use can delay the signs of skin aging, even in middle age. Unfortunately, it also found that supplementing your diet with antioxidants, in this case beta-carotene, has little effect on skin aging.

After four and a half years, the daily sunscreen groups showed no detectable changes in signs of skin aging.

“We were not surprised by these findings,” Adèle Green, lead author on the study, told TheDoctor in an e-mail. Although it has long been known that most signs of skin aging are the result of cumulative damage following years of sun exposure, she said, this is the first scientific evidence of the benefits of sunscreen use in humans.

The take-away is that regular sunscreen use by young and middle-aged people prevents or slows down progressive skin aging, and at the same time decreases the risk of skin cancer over the long term, according to Green, head of the Cancer and Populations Studies Group and deputy director of the Queensland Institute of Medical Research.

It is important to note that most of the participants in the Australian study were fair-skinned, and fair-skinned persons tend to show more signs of skin aging as compared to those with darker skin, Gervaise Gerstner, tells TheDoctor. Gervaise, an assistant clinical professor of dermatology at the Mount Sinai School of Medicine in New York, goes on to say that, “You would not want to apply [the findings of this study] to the whole world, because this was specifically done on fair-skinned persons. ”

The investigators randomly assigned 903 men and women under 55 to one of four groups: daily use of broad-spectrum sunscreen and 30 mg of beta-carotene; daily use of sunscreen and placebo; discretionary use of sunscreen and 30 mg of beta-carotene; and discretionary use of sunscreen and placebo.

After four and a half years, the daily sunscreen groups showed no detectable changes in signs of skin aging. Compared to the discretionary sunscreen groups, the regular sunscreen groups showed 24 percent less evidence of skin aging at the end of the trial, regardless of age. The researchers also found that the beta-carotene supplements did not have any effect on skin aging.

In the future, the group plans to study whether when younger people — under 55 — use sunscreen regularly, the benefits to their skin last even beyond the immediate period of regular application. The researchers are also interested in whether a person’s dietary habits influence progression of skin aging.

The study is published online in Annals of Internal Medicine.