Role in the Body and Consequences of Deficiency

The only specific effect of carotenoids in humans is to act as a source of vitamin A in the diet, but they also have important antioxidant actions. The latter are based on the carotenoids’ ability to quench singlet oxygen and trap peroxyl radicals, thereby preventing lipid peroxidation [50]. As a result, carotenoids protect against the development of cancer, CVD, and ocular disorders. Carotenoids also affect cell growth regulation and gene expression. Diets low in carotenoids may lead to increased risk of cancer and heart disease. Lycopene is the most potent antioxidant for quenching single oxygen and scavenging free radicals [51].

Isotretinoin currently is approved for the treatment of nodulocystic acne, and there have been reported benefits in using 10–20 mg three times a week for 2 months for the treatment of cutaneous aging [59].