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Lycopene helps prevent colon cancer

STUTTGART, GERMANY. Polyps are abnormal growths originating in the lining of the colon (large intestine). There are two kinds of polyps – adenomatous polyps (adenomas), which are believed to be precursors for colon cancer, and hyperplastic polyps, which are considered to be benign. The presence of polyps is usually established via colonoscopy.

German researchers now report that the presence of adenomas is associated with a low blood plasma level of lycopene. Lycopene, along with beta-carotene, is a member of the carotenoid family, and is a very powerful antioxidant, especially effective in neutralizing singlet oxygen radicals. Tomatoes and processed tomato products are good sources of lycopene. Other sources are watermelon, papaya, guava, and pink grapefruit. Lycopene is also available in supplement form.

The researchers checked 165 patients for polyps with a complete colonoscopy and found that 63 (controls) had no polyps, 29 had hyperplastic polyps, and the remaining 73 had colorectal adenomas. The researchers also measured plasma levels of lycopene, beta-carotene, and alpha-tocopherol (vitamin E). They found that patients with adenomas had, on average, a significantly lower level of lycopene (52 micrograms/L) than did controls and patients with hyperplastic polyps (80 micrograms/L). There were no significant differences in the levels of beta-carotene and alpha-tocopherol among the three groups of patients. After adjusting for age, gender, alcohol consumption, smoking, body mass index (BMI), and low concentrations of alpha-tocopherol and beta-carotene the researchers observed that only two variables were associated with a higher risk of adenomas. Smoking increased the risk by 300% and a plasma lycopene concentration below 70 micrograms/L increased it by 231% (odds ratio: 2.31). They conclude that plasma lycopene concentrations are inversely associated with adenoma risk and point out that low lycopene levels have also been associated with an increased risk of lung, stomach and prostate cancers.
Erhardt, JG, et al. Lycopene, beta-carotene, and colorectal adenomas. American Journal of Clinical Nutrition, Vol. 78, December 2003, pp. 1219-24

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