sunscreens

Broad-spectrum sunscreens are now widely used worldwide as an adjunct to help prevent sunburn, skin cancers and premature skin aging. In the United States, all persons older than 6 months are recommended to apply sunscreen to all sun-exposed skin from toes to head except eyes and mouth even on cloudy days. Such a recommendation is apparently based on concepts that exposure to sunlight damages the skin, the damage is cumulative and hence any sun exposure should be minimized or prevented. This communication raises several questions suggesting that the above recommendation may need to be reconsidered. For example, numerous previous studies have indicated many potential health benefits from non-burning sun exposure including protection against sunburn, melanoma, colorectal cancer, breast cancer and prostate cancer, increasing vitamin D synthesis, helping sleep, reducing blood pressure, heart attack and stroke. Recent studies suggested that regular lifetime non-burning sun exposure may not result in premature skin aging and the skin aging is mainly caused by the intrinsic factor. Skin aging or whole-body aging has been recently postulated to be mainly attributed to a gradual reduction in cardiac output/index with age and a new anti-aging or age-reversing nutritional theory has been proposed. An apparent lack of long-term cumulative sunray damage was also supported by reported age independence in incidences of sunburn and skin cancers. It is of interest that the current US policy is different from that of World Health Organization and Australia recommending the need of sun protection only when UV Index is 3 or greater. In view of the above, some general guidelines regarding when to best apply sunscreen are proposed.