e lignan antioxidants (Osawa, 1994, 78). Catechins in tea also act as antioxidants, and are known as theaflavins (79). They have been shown to inhibit the cleavage of DNA by hydrogen peroxide in the presence of cytochrome c, and are expected to protect against DNA damage in cells. Thus they offer a protective mechanism against free radical damage. Curcumin is the main ingredient in tumeric and has demonstrated antioxidant activity (79). It contains a phenol moiety and a beta-diketone moiety. It acts as a strong inhibitor of tumor promotion.
To protect the skin against the effects of aging caused by free radicals, mostly ultraviolet radiation, selenium, and vitamins E and C have been recommended (Gorgos, 2002). Selenium is a mineral required for the antioxidant glutathione peroxidase, which protects against cancers, particularly skin cancer due to sun exposure (206). It also preserves the elasticity of tissues, and slows down the aging process and hardening of tissues. Selenium can be obtained from the diet in whole grain cereals, seafood, garlic, and eggs (207). It can also be taken as a mineral supplement in tablet form.
Vitamin E is the most important antioxidant the body contains, and protects cell membranes and membrane-associated enzymes from damage by free radicals. Regular supplements of vitamin E, in conjunction with supplements of vitamin A, can result in a 70 percent reduction in the risk of basal cell carcinomas, a common form of skin cancer. In the diet, vitamin E is found in vegetable oils (particularly sunflower oil), margarine, grains, nuts, meats, and dairy products. It can be found in skin creams or taken as supplements in capsule form.
Vitamin C is the most abundant antioxidant occurring naturally in the skin, but is depleted from the skin by exposure to the sun, smoking, and air pollution (207). It is found in fruits, vegetables, and processed fruit juices, or can be taken as a supplement...