Nutrition plays an important role in the treatment of many diseases, and the right choice of nutrients can help to prevent disorders and improve the quality of life. Epidemiologic studies suggest that there is a close relationship between ultraviolet exposure (high level of reactive oxygen species) and the intake of specific dietary factors (eg antioxidants), and the diminished risk of developing cancer, coronary heart disease, or cataracts. Free radicals and reactive oxygen species are synthesized endogenously (eg, in energy metabolism and the antimicrobial defense system of the body) or produced as reactions to exogenous exposure (eg, cigarette smoke, imbalanced diet, exhaustive exercise, environmental pollutants, and food contaminants). Human dietary intervention studies based on the use of antioxidant compounds show how they can protect from endogenous and exogenous environmental assaults, and neutralize sun-induced effects on the skin. The future challenge will be to combine the strategic use of cosmeceuticals and nutraceuticals in preventing the damaging effects of ultraviolet radiation and environmental pollutants on the many biologic processes involving skin aging and cancer.