ABSTRACT

Free radicals induce various cellular injuries (including lipid peroxidation, DNA alteration, and protein inactivation) that may be involved in the etiology of degenerative diseases such as cancer, cardiovascular diseases, and neurodegenerative diseases.1-3 There is now overwhelming evidence of an inverse relationship between a diet high in antioxidants and the incidence of disease.4-6 Epidemiological and laboratory studies indicate that high consumption of antioxidant-rich fruits and vegetables can reduce the risk of cancer.6-9 Currently, the U.S. Department of Agriculture and the National Cancer Institute recommend the consumption of a minimum of five servings of fruits and vegetables per day to prevent cancer.10 Vitamin C is one of the most prevalent antioxidants in fruits and vegetables, and is considered to exert chemopreventive effects without apparent toxicity at doses substantially higher than the current recommended daily allowance

(RDA) of 60 mg/day.10 Vitamin C has also been used as a dietary supplement for the prevention of oxidative-stress-mediated chronic diseases such as cancer, cardiovascular disease,11 hypertension,12 stroke,13 and neurodegenerative disorders.3 In 1997, expert panels at the World Cancer Research Fund and the American Institute for Cancer Research asserted that vitamin C can reduce the risk of stomach, mouth, pharynx, esophagus, lung, pancreas, and cervical cancers.10