Natural Therapeutics : Anti - Photoaging by Stephen Holt , MD , and Ester

Introduction Ultraviolet radiation (UVR) in sunlight is the most important cause of skin damage and aging.'"' This form of radiation causes skin aging by several mechanisms, including free-radical generation, DNA damage, collagen breakdown, the induction of immune defects, and cell death.'-5 In addition, repeated damage to the skin by sunburn is a primarily risk factor for the development of cutaneous neoplasia, including melanoma. V^hile photoaging may be considered to be the pivotal cause of skin aging or damage, other factors operate.'** Cigarette smoking, various environmental pollutants, and synthetic chemicals (including those present in cosmetic products or sunscreens) can all contribute to dermal pathology and perhaps skin aging.' These external factors may often combine with "intrinsic propensities" to aging. Intrinsic skin aging is characterized by thinning of dermal and epidermal layers of the skin coincidental with the evolution of "immune senescence.'"'̂ The recognition that photoaging is caused primarily by ultraviolet radiation (UVR) has led to conventional wisdom that excessive exposure to sunshine should be avoided. The risks of cutaneous sun damage have led to the widespread application of techniques to protect the skin from sunlight, most often using sun-screening techniques. The objectives of this article are to examine factors that propagate skin phototoxicity (photoaging) and look at natural ways to combat this major public health concern.