TORONTO, CANADA. Lycopene is a carotenoid found in tomatoes, tomato products, and in other fruits. It is a powerful antioxidant with a singlet-oxygen quenching capacity 10 times greater than that of vitamin E. It is the most abundant carotenoid in human plasma and is highly concentrated in the adrenal glands, testes, prostate, and breast tissue. Several studies have found an inverse correlation between serum and tissue levels of lycopene and the risk of breast and prostate cancers. Other studies have linked a high intake of tomatoes to a 50 per cent reduction in cancer mortality among elderly Americans. One study found that men who consumed 10 or more servings of tomato products per week reduced their risk of prostate cancer by 35 per cent. A more recent study found that supplementation with a tomato extract significantly lowered the level of prostate-specific antigen (PSA) in patients with prostate cancer. High tissue (adipose) levels of lycopene have also been found to be protective against heart attacks. No published studies have shown any adverse effects of high lycopene levels or a high intake of tomato products. It has been hypothesized that lycopene prevents cancer and heart disease by protecting lipids, lipoproteins (especially low-density lipoprotein), proteins, and DNA. There is also evidence that lycopene counteracts the proliferation of cancer cells induced by insulin-like growth factors.
Agarwal, Sanjiv and Rao, AV. Tomato lycopene and its role in human health and chronic diseases. Canadian Medical Association Journal, Vol. 163, September 19, 2000, pp. 739-44 [70 references]