Introduction
Lycopene, the carotenoid that provides the red colour to tomatoes and watermelon, concentrates in the male prostate gland where it is thought to act as an antioxidant and provide other protective effects against prostate cancer. Lycopene represents as much as 50% of the carotenoids found in human serum. Lycopene demonstrates a high level of bioavailability, which is enhanced when tomatoes and other lycopene-containing vegetables and fruits are heated, chopped and processed. This explains why tomato sauce is such a good and bioavailable source of lycopene. Lycopene has been shown to concentrate in the prostate gland, adrenals, testes, skin, liver and kidneys. The body cannot convert lycopene into Vitamin A, as it can with some other carotenoids (e.g. beta-carotene), but lycopene demonstrates powerful antioxidant activity and is the most effective quencher of oxygen free radicals among the many carotenoids found in nature, being twice as potent as beta-carotene in this regard. In addition to its role as an antioxidant lycopene demonstrates a number of other anti-cancer properties. Under experimental conditions lycopene is able to reduce lung adenomas and carcinomas, colon cancer, prostate cancer, breast (mammary) tumor, and to inhibit endometrial cancer as well as HL-60 leukemic cell growth.
Epidemiological evidence indicates that the ingestion of tomato products is associated with a reduction in risk of overall cancer mortality or incidence. The evidence appear to be strongest for reduced risk of pancreatic, rectal, colon, esophageal, oral, cervical, breast and prostate cancer. The Mediterranean-type diet in particular, which has a higher intake of tomato products, is associated with lower incidence of digestive tract cancers.
Fazekas Z, Gao D, Saladi RN et al. Protective effects of lycopene against ultraviolet B-induced photodamage. Nutr and Cancer 2003, 47;2: 181-187
Prostate Cancer
Lycopene intake of 6.5 mg per day has been linked to a 21% decreased risk of prostate cancer compared with those consuming the least. This study also reported that those who ate more than ten servings per week of tomato-based foods had a 35% decreased risk of prostate cancer compared with those eating less than 1.5 weekly servings.1
Lycopene is the most abundant carotenoid in the prostate2, and high blood levels of Lycopene have been linked to prostate cancer prevention,3 including prospective or longitudinal studies.4
Women’s Health
Higher intakes of Lycopene have also been associated with a lower risk of cervical intraepithelial neoplasia – precancerous changes of the cervix and cervical dysplasia.5-8 Some preliminary evidence also suggests that Lycopene may help reduce the risk of breast cancer.9
Cardiovascular Disease
Observational and experimental studies also suggest that Lycopene may reduce risk of heart disease (up to 48% lower risk reported).10 Lycopene may reduce LDL-C oxidation, inhibit cholesterol synthesis in the liver, or enhance LDL degradation.11 Intervention trials are required to see if Lycopene can prevent cardiovascular disease to the degree suggested by these observational and experimental studies.
Cancer in General
Lycopene may help to reduce risk of cancer through its antioxidant function, immune modulating effects and/or its antiproliferative influence. Recent studies have shown that high insulin-like growth factor I (IGF-I) blood levels is a risk factor in breast and prostate cancer. Lycopene has been shown to reduce IGF-I stimulation leading to an antiproliferative effect on various cancer cell lines including breast, endometrial and lung.12,13
Immune System
Lycopene supplementation has also boosted immune function in the elderly (15 mg of Lycopene per day increased natural killer cell activity by 28% in twelve weeks).14
Adverse Side Effects and Toxicity
No reports of toxicity have been reported to date with Lycopene supplementation.14,15
Drug Nutrient Interactions
The following drugs are reported to decrease the absorption of Lycopene and thus, should not be ingested at the same time as Lycopene:
Mineral Oil16
Orlistat17,18,19
Bile Acid Sequestrants20,21
Olestra containing products22,23
Chitosan24
Giovannucci E, Ascherio A, Rimm EB, et al. Intake of carotenoids and retinal in relation to risk of prostate cancer. J Natl Cancer Inst 1995;87:1767-76.
Carter HB, Coffey DS. The prostate: an increasing medical problem. Prostate 1990;16:39-48.
Hsing AW, Comstock GW, Abbey H, Polk F. Serologic precursors of cancer. Retinol, carotenoids, and tocopherol and risk of prostrate cancer. J Natl Cancer Inst 1990;82:941-6.
Gann PH, Ma J, Giovannucci E, Willett W, Sacks FM, Hennekens CH, et al . Lower prostate cancer risk in men with elevated plasma lycopene levels: results of a prospective analysis (physicians health study). Cancer Res 1999;59(6):1225-30.
Van Eenwyk J, Davis FG, Bowne PE. Dietary and serum carotenoids and cervical intraepithelial neoplasia. Int J Cancer 1991 ;48:34-38.
Kanetsky PA, Gammon MD, Mandelblatt J, Zhang ZF, Ramsey E, Dnistrian A, et al. Dietary intake and blood levels of lycopene: an association with cervical dysplasia among non-hispanic, black women. Nutr Cancer 1998;31:31-40.
Cuzik J, Stavola BL, Russell MJ, Thomas BS. Vitamin A, Vitamin E and risk of cervical intraepithelial neoplasia. Br J Cancer 1990;62:651-2.
La Vecchia C, Decarli A, Fasoli M, Parazzini F, Franceschi S, Gentile A, et al. Dietary Vitamin A and the risk of intraepithelial and invasive cervical neoplasia. Gynegol Oncol 1988;30:187-95.
Dorgan, JF, Sowell A, Swanson CA, Potischman N, Miller R, Schussler N, et al. Relationships of serum carotenoids, retinal, alpha- tocopherol, and selenium with breast cancer risk. Cancer Causes Control 1998;9:89-97.
Kohlmeyer L , Kark JD, Gomez-Gracia E, et al. Lycopene and myocardinal infarction risk in the EUROMIC study. Am J Epidemiol 1997;146:618-26.
Arab L, Steck S. Lycopene and cardiovascular disease. Am J Clin Nutr 2000;71 (6Suppl):1691S-5S.
Karas M, Amir H, Fishman D, Danilenko M, Segal S, Nahum A, et al. Lycopene interferes with cell cycle progression and insulin-like growth factor 1 signalling in mammary cancer cells. Nutr Cancer 2000;36(1 ):101-11.
Levy J, Bosin E, Feldman B, Giat Y, Milinster, Danilenko M, 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.
Corridan BM, O'Donohue MP, Morrissey PA. Carotenoids and immune response in elderly people. Proc Nutr Soc 1998;3(Abstract):57A.
Hathcock JN. Evaluation of Vitamin A toxicity. Am J Clin Nutr 1990;52:183-202.
Diarrhea and constipation. In: Berkow R, Fletcher AJ, Beers MH, et al, editors. The Merck manual of diagnosis and therapy. 16th ed. Rahway, NJ: Merck Research Laboratories; 1992. p. 810.
Heck AM, Yanovski, Calis KA. Orlistat, a new lipase inhibitor for the management of obesity. Pharmacotherapy 2000;20(3):270-9.
Xenical (orlistat), product prescribing information. Nutley, NJ: Roche Laboratoris Inc;2000.
Finer N, James WP, Kopelman PG, Lean ME, Williams G. One-year treatment of obesity: a randomized, double-blind, placebo-controlled, mulicentre study of orlistat, a gastrointestinal lipase inhibitor. Int J Obes Relat Metab Disord 2000;24(3):3006-13.
Schwarz KB, Goldstein PD, Witztum JL, Schonfeld G. Fat-soluble vitamin concentrations in hypercholesterolemic children treated with colestipol. Pediatrics 1980;65(2):243-50.
Knodel LC, Talbert RL. Adverse effects of hypolipidaemic drugs. Med Toxicol 1987:2(1)10-32.
Koonsvitsky BP, Berry DA, Jones MB, Lin PY, Cooper DA, Jones DY, et al. Olestra affects serum concentrations of alpha-tocopherol and carotenoids but not Vitamin D or Vitamin K status in free-living subjects. J Nutr 1997; 127(8Suppl): 1636S-45S.
Thomson AB, Hunt RH, Zorich NL. Review article: Olestra and its gastrointestinal safety. Aliment Pharmacol Ther 1998;12(12):1185-200.
Deuchi K, Kanauchi O, Shizukuishi M, Kobayashi E. Continuous and massive intake of chitosan affects mineral and fat-soluble vitamin status in rats fed on a high-fat diet. Biosci Biotechnol Biochem 1995;59(7):1211-6.
Additional Lycopene References
Bramley PM. Is Lycopene beneficial to human health? Medscape Medline Abstract. Accessed Sept 10, 2000.
Klebanov GI, Kapitanov AB, Teselkin YO, Babenkova IV, Zhambalova BA, Lyubitsky OB et al. The antioxidant properties of Lyconpene. Medscape Medline Abstract. Accessed Sept 10, 2000.
Sharoni Y, Giron E, Rise M, Levy J. Effects of Lycopene-enriched tomato oleoresin on 7,12-dimethyl-benz[a]anthracene-induced rat mammary tumors. Medscape Medline Abstract. Accessed Sept 10, 2000.
Stahl W, Sies H. Lycopene: a biologically important carotenoid for humans? Medscape Medline Abstract. Accessed Sept 10, 2000.
Khachik F, Beecher GR, Smith JC Jr. Lutein, Lycopene, and their oxidative metabolites in chemoprevention of cancer. Medscape Medline Abstract. Accessed Sept 10, 2000.
Rao AV, Argarwal S. Bioavailability and in vivo antioxidant properties of Lycopene from tomato products and their possible role in the prevention of cancer. Medscape Medline Abstract. Accessed Sept 10, 2000.