Nature’s Most Potent Antioxidant Shows Broad Disease-Preventive EffectsDecember 2004
By Liz Nakazawa
Lycopene, a powerful plant-based antioxidant nutrient, may offer protection from both cancer and heart disease. Lycopene is fast becoming known as nature’s most potent antioxidant, with tremendous potential for helping to prevent disease and extend the healthy human life span.
Lycopene, a natural pigment synthesized by plants and microorganisms, is a member of the carotenoid family. The carotenoids are yellow, orange, and red pigments that include beta-carotene. Found in fruits and vegetables, the carotenoids are known for their potent antioxidant capabilities.
Lycopene gives tomatoes their reddish color. Indeed, tomato products such as spaghetti sauce are the richest food sources of lycopene, accounting for over 85% of the lycopene in the North American diet. Other foods such as watermelon, guava, and pink grapefruit contain smaller amounts of lycopene. Lycopene’s bioavailability is influenced by heat, so cooked tomato products are better sources of lycopene than are raw tomatoes.1 Because it is a fat-soluble nutrient, lycopene is best absorbed when consumed with a source of dietary fat.2
Lycopene scavenges and neutralizes free radicals, preventing oxidative damage that is associated with a number of chronic diseases.3 Of the common nutrients people supplement with—including vitamins E and C, and beta-carotene—lycopene has been shown to be the most efficient quencher of free radicals.4
While lycopene is best known for its role in the prevention of prostate cancer, current research suggests it may be valuable in guarding against other cancers, including lung, pancreatic and breast cancer, as well as in offering protection against cardiovascular disease.
Good For Your Prostate
In a recent study in China, researchers found that individuals consuming abundant dietary carotenoids, including lycopene, had a reduced risk of prostate cancer.6 Another study demonstrated that consumption of two to four servings of tomato sauce per week was associated with a 35% risk reduction in total prostate cancer and a 50% reduction of advanced (extraprostatic) cancer.7
Human prostate tissue is vulnerable to oxidative DNA damage.8 As a powerful antioxidant, lycopene has been demonstrated to significantly lower oxidative DNA damage in prostate tissue.8 Lycopene supplementation in men with prostate cancer has also been found to lower levels of prostate-specific antigen (PSA), a widely used marker of prostate cancer progression and response to treatment.9 (Elevated levels of PSA can also occur with age-related prostate enlargement and benign prostatic hyperplasia.)
Effects Against Other Cancers
Lycopene has been found to inhibit the proliferation of several types of human cancer cells in vitro, including lung and breast cancer cells.11 Moreover, in-vivo studies have shown lycopene has tumor-suppressive activity.12 Lycopene helped prevent the development of spontaneous mammary tumors in a strain of mice that are highly susceptible to tumor development.12
Lung cancer is the leading cause of cancer death in America. Animal studies suggest that dietary lycopene helps reduce the risk of lung cancers. Dietary lycopene dissolved in drinking water over the course of 21 weeks significantly decreased two types of lung adenomas along with carcinomas in male mice.13
Breast cancer is the second leading cause of cancer death in American women. Epidemiological studies have suggested that lycopene has a protective effect against breast cancer. Low levels of lycopene in the diet and in blood have been correlated with an increased risk of breast cancer.10 In cell cultures, lycopene has been found to inhibit breast tumors more efficiently than alpha-carotene and beta-carotene.11
Lycopene and Heart Disease
European researchers studied lycopene concentration and risk for cardiovascular disease. They found that men with the highest levels of lycopene in their adipose tissue were 48% less likely to develop cardiovascular disease. They also found that while lycopene consumption was cardioprotective, alpha-carotene and beta-carotene were not.14
Women also benefit from lycopene. A 2003 study by Harvard researchers found that women with the highest intake of lycopene had a reduced risk of cardiovascular disease compared to women with a low intake of lycopene. Women who consumed seven or more servings of tomato-based foods weekly saw a nearly 30% risk reduction in total cardiovascular disease compared to a group with intakes of less than 1.5 servings per week.15
A study in Finland measured lycopene blood levels and the thickness of the carotid artery wall. Researchers found a strong correlation between low blood lycopene concentrations and thickening of the carotid artery, which is associated with an increased risk of heart attack.16 The study authors concluded that low plasma lycopene concentrations are associated with early atherosclerosis.
Absorption and Toxicity
Lycopene is considered safe and non-toxic, and consumption is usually without side effects. Ingestion of extremely large quantities of lycopene has been associated with lycopenemia, a benign condition marked by an orange-yellow pigmentation of the skin.18
While scientific evidence concerning lycopene use in pregnancy is not available, no adverse effects have been reported in pregnant women consuming foods containing lycopene. During pregnancy and nursing, it is best to obtain lycopene from food sources rather than from supplements.
How Much Should You Take?
With its protective effects against America’s two leading killers—cardiovascular disease and cancer—lycopene should be considered an essential part of every healthy diet and supplement regimen.
1. Agarwal A, Shen H, Agarwal S, Rao AV. Lycopene content of tomato products: Its stability, bioavailability, and in vivo antioxidant properties. J Med Food. 2001 Spring;4(1):9-15.
2. Brown MJ, Ferruzzi MG, Nguyen ML, et al. Carotenoid bioavailability is higher from salads ingested with full-fat than with fat-reduced salad dressings as measured with electrochemical detection. Am J Clin Nutr. 2004 Aug;80(2):396-403.
3. Linseisen J, Hoffman J, Riedl J, Wolfram G. Effect of a single oral dose of antioxidant mixture (vitamin E, carotenoids) on the formation of cholesterol oxidation products after ex vivo LDL oxidation in humans. Eur J Med Res. 1998 Feb 21;3(1-2):5-12.
4. Di Mascio P, Kaiser S, Sies H. Lycopene as the most efficient biological carotenoid singlet oxygen quencher. Arch Biochem Biophys. 1989 Nov 1;274(2):532-8.
5. Giovannucci E, Rimm EB, Liu Y, Stampfer MJ, Willett WC. A prospective study of tomato products, lycopene, and prostate cancer risk. J Nal Cancer Inst. 2002 Mar 6;94(5):391-8.
6. Binns CW, LJ LJ, Lee AH. The relationship between dietary carotenoids and prostate cancer risk in Southeast Chinese men. Asia Pac J Clin Nutr. 2004; 13(Suppl):S117.
7. Giovannucci E. A review of epidemiological studies of tomatoes, lycopene, and prostate cancer. Exp Biol Med. 2002 Nov;227(10):852-9.
8. Chen L, Stacewicz-Sapuntzakis M, Duncan C, et al. Oxidative DNA damage in prostate cancer patients consuming tomato sauce-based entrees as a whole-food intervention. J Natl Cancer Inst. 2001 Dec 19;93(24):1872-9.
9. Bowen P, Chen L, Stacewicz-Sapuntzakis M, et al. Tomato sauce supplementation and prostate cancer: lycopene accumulation and modulation of biomarkers of carcinogenesis. Exp Biol Med. 2002 Nov;227(10):886-93.
10. Rao AV, Agarwal S. Role of antioxidant lycopene in cancer and heart disease. J Am Col Nutr. 2000 Oct; 19(5):563-9.
11. Levy J, Bosin E, Feldman B, et al. Lycopene is a more potent inhibitor of human cancer cell proliferation than either alpha-carotene or beta-carotene. Nutr Cancer. 1995;24(3):257-66.
12. Nagasawa H, Mitamura T, Sakamoto S, Yamamoto K. Effects of lycopene on spontaneous mammary tumour development in SHN virgin mice. Anticancer Res. 1995 Jul-Aug;15(4):1173-8.
13. Kim DJ, Takasuka N, Kim NJ, et al. Chemoprevention by lycopene of mouse lung neoplasia after combined initiation treatment with DEN, MNU and DMH. Cancer Lett. 1997 Nov 25;120(1):15-22.
14. Kohlmeier L, Kark JD, Gomez-Gracia E, et al. Lycopene and myocardial infarction risk in the EURAMIC Study. Am J Epidemiol. 1997 Oct 15;146(8):618-26.
15. Sesso HD, Liu S, Gaziano JM, Buring JE. Dietary lycopene, tomato-based food products and cardiovascular disease in women. J Nutr. 2003 Jul;133(7):2336-41.
16. Rissanen T, Voutilainen S, Nyyssonen K, Salonen R, Salonen JT. Low plasma lycopene concentration is associated with increased intima-media thickness of the carotid artery wall. Arterioscler Throm Vasc Biol. 2000 Dec;20(12):2677-81.
17. Riedl J, Linseisen J, Hoffmann J, Wolfram G. Some dietary fibers reduce the absorption of carotenoids in women. J Nutr. 1999 Dec;129(12):2170-6.