Tomatoes, tomato-based products, lycopene, and cancer: review of the epidemiologic literature

TLP — Tue, 03 Jul 2007 18:13:38 +0000

The epidemiologic literature in the English language regarding intake of tomatoes and tomato-based products and blood lycopene (a compound derived predominantly from tomatoes) level in relation to the risk of various cancers was reviewed. Among 72 studies identified, 57 reported inverse associations between tomato intake or blood lycopene level and the risk of cancer at a defined anatomic site; 35 of these inverse associations were statistically significant. No study indicated that higher tomato consumption or blood lycopene level statistically significantly increased the risk of cancer at any of the investigated sites. About half of the relative risks for comparisons of high with low intakes or levels for tomatoes or lycopene were approximately 0.6 or lower. The evidence for a benefit was strongest for cancers of the prostate, lung, and stomach. Data were also suggestive of a benefit for cancers of the pancreas, colon and rectum, esophagus, oral cavity, breast, and cervix. Because the data are from observational studies, a cause-effect relationship cannot be established definitively. However, the consistency of the results across numerous studies in diverse populations, for case-control and prospective studies, and for dietary-based and blood-based investigations argues against bias or confounding as the explanation for these findings. Lycopene may account for or contribute to these benefits, but this possibility is not yet proven and requires further study. Numerous other potentially beneficial compounds are present in tomatoes, and, conceivably, complex interactions among multiple components may contribute to the anticancer properties of tomatoes. The consistently lower risk of cancer for a variety of anatomic sites that is associated with higher consumption of tomatoes and tomato-based products adds further support for current dietary recommendations to increase fruit and vegetable consumption.

Giovannucci E.

Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA 02115, USA. edward.giovannucci@channing.harvard.edu

J Natl Cancer Inst. 1999 Feb 17;91(4):317-31.

Serum Lycopene, Other Carotenoids, and Prostate Cancer Risk: a Nested Case-Control Study in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

TLP — Tue, 03 Jul 2007 18:06:58 +0000

Background: Reports from several studies have suggested that carotenoids, and in particular lycopene, could be prostate cancerâ€“preventive agents. This has stimulated extensive laboratory and clinical research, as well as much commercial and public enthusiasm. However, the epidemiologic evidence remains inconclusive.

Materials and Methods: We investigated the association between prediagnostic serum carotenoids (lycopene, {alpha}-carotene, ÃŸ-carotene, ÃŸ-cryptoxanthin, lutein, and zeaxanthin) and risk of prostate cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, a multicenter study designed to examine methods of early detection and risk factors for cancer. The study included 692 incident prostate cancer cases, diagnosed 1 to 8 years after study entry, including 270 aggressive cases, with regional or distant stage (n = 90) or Gleason score â‰¥7 (n = 235), and 844 randomly selected, matched controls. As study participants were selected from those who were assigned to annual standardized screening for prostate cancer, results are unlikely to be biased by differential screening, a circumstance that is difficult to attain under nonâ€“trial conditions.

Results: No association was observed between serum lycopene and total prostate cancer [odds ratios (OR), 1.14; 95% confidence intervals (95% CI), 0.82-1.58 for highest versus lowest quintile; P for trend, 0.28] or aggressive prostate cancer (OR, 0.99; 95% CI, 0.62-1.57 for highest versus lowest quintile; P for trend, 0.433). ÃŸ-Carotene was associated with an increased risk of aggressive prostate cancer (OR, 1.67; 95% CI, 1.03-2.72 for highest versus lowest quintile; P for trend, 0.13); in particular, regional or distant stage disease (OR, 3.16; 95% CI, 1.37-7.31 for highest versus lowest quintile; P for trend, 0.02); other carotenoids were not associated with risk.

Conclusion: In this large prospective study, high serum ÃŸ-carotene concentrations were associated with increased risk for aggressive, clinically relevant prostate cancer. Lycopene and other carotenoids were unrelated to prostate cancer. Consistent with other recent publications, these results suggest that lycopene or tomato-based regimens will not be effective for prostate cancer prevention.

(Cancer Epidemiol Biomarkers Prev 2007;16(5):962â€“8)

Full Text

Ulrike Peters1,2,3, Michael F. Leitzmann3, Nilanjan Chatterjee3, Yinghui Wang1, Demetrius Albanes3, Edward P. Gelmann4, Marlin D. Friesen5, Elio Riboli6 and Richard B. Hayes3

1 Fred Hutchinson Cancer Research Center; 2 University of Washington, Seattle, Washington; 3 Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Department of Health and Human Services, Rockville, Maryland; 4 Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, District of Columbia; 5 Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; and 6 Nutrition and Cancer Unit, International Agency for Research on Cancer, Lyon, France

Requests for reprints: Ulrike Peters, Cancer Prevention Program, Fred Hutchinson Cancer Research Center, P.O. Box 19024, 1100 Fairview Avenue North M4-B402, Seattle, WA 98109-1024. Phone: 206-667-2450; Fax: 206-667-7850. E-mail: upeters@fhcrc.org

The Longevity Project » lycopene

Tomatoes, tomato-based products, lycopene, and cancer: review of the epidemiologic literature

Serum Lycopene, Other Carotenoids, and Prostate Cancer Risk: a Nested Case-Control Study in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial