Lycopene and Prostate Cancer
The Tomato Magazine
The scientists used an animal prostate cancer model to mimic human cancer. The animals were fed lycopene, vitamin E, a combination of both or a placebo mixture for four weeks, and then received an injection of prostate cancer cells into their prostates. These cancer cells grew into tumors within a further two weeks. Feeding lycopene as well as vitamin E caused an increased death rate of tumor cells, which was shown by larger areas of dead tissue in the prostate tumors.
To explore the molecular mechanisms by which feeding lycopene and vitamin E caused more tumor cells to die, the scientists applied a new modern technology, "Nutrigenomics", to monitor the expression of thousands of genes in the tumors. Their analysis revealed that both nutrients affected gene expression directly in the tumors: Lycopene interfered with local androgen activation by down-regulating 5-±-reductase, the key enzyme for the transformation of testosterone to its most active form, dehydrotestosterone. As a consequence, the expression of androgen-regulated target genes was also reduced. In addition, lycopene decreased the expression of two prostatic cytokines, IGF-I and IL-6, both regarded as risk factors for prostate cancer. Vitamin E reduced androgen signaling without affecting androgen metabolism.
These results show that the pure lycopene molecule targets a key mechanism which drives the development of prostate cancer. They provide a mechanistic explanation for the epidemiological findings that men with higher tomato-based food intakes are less likely to develop prostate cancer. Men eating 4-5 tomato-based meals per week were found to be protected 25% better compared to men eating tomatoes only rarely. This would be equivalent to approximately 6 mg of lycopene per day. The tomatoes must be cooked and served with some oil to make the lycopene molecule available for the body. DSM synthetic lycopene has proved to have a similar bioavailability to lycopene from tomato-based foods such as soups.
The results found for vitamin E contribute to the body of evidence emerging from a long-term intervention trial (alpha-Tocopherol beta-Carotene study) in Finland, indicating a beneficial role of synthetic vitamin E in the prevention of prostate cancer. A currently running intervention trial in the US, the SELECT trial, is aimed to substantiate this evidence further. With these findings, research has made another significant step towards elucidating the important role of the nutritional compounds lycopene and vitamin E in disease prevention.
DSM Nutritional Products offers excellent, highly stable lycopene formulations for a wide range of applications: Lycopene 5% TG/P for direct compression tablets, Lycopene 20 percent FS for soft-gelatin capsules, and Lycopene 10 percent WS for the fortification of foods and beverages.
Reference: U. Siler, L. Barella, V. Spitzer, J. Schnorr,
M. Lein, R. Goralczyk, K. Wertz, FASEB J (2004) doi:10.1096/fj.03-1116fje.
© 2005 Columbia Publishing
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