Epidemiology studies have suggested protection against prostate cancer is derived from consuming tomato products or a major carotenoid found in them, lycopene. The heterogenous nature of prostate cancers, and the difficulty in having precise measures of tomato consumption makes it hard to fully understand the impact of tomato products on prostate cancer, and importantly to establish a causal relation between them. Therefore, to design effective human intervention studies, it is necessary to define optimal methods for delivery (food vs pure lycopene), the dose, duration, and timing of exposures. Moran and colleagues have performed a review of the literature for various animal models of prostate cancer in order to explore these variables in controlled experiments and report the results of their review in the June 2022 issue of The Journal of Nutrition.
Data were derived from 21 published reports of the impact of different doses of tomatoes, tomato components, or lycopene on tumorigenesis and carcinogenesis in different rodent models. The models included transplantable xenografts, or chemically- and genetically-driven prostate cancers.
Both tomatoes and tomato components were able to suppress tumorigenesis in the transplant and carcinogenesis in the chemically- and genetically-driven cancer types. Lycopene was effective in most model systems, but the response was dependent on dose, duration, and type of carcinogenic process. Efficacy was typically higher when the interventions were started earlier and lasted longer. The data suggest that lycopene may not be the only compound in tomatoes with anti-prostate cancer activity. The authors conclude that tomatoes and lycopene have anti-cancer activity in rodent models, yet acknowledge that more work is needed to explain dose-response relationships and identify molecular mechanisms of action. They suggest future studies could provide the information needed to design and execute effective human clinical trials.
References
Nancy E Moran, Jennifer M Thomas-Ahner, Lei Wan, Krystle E Zuniga, John W Erdman, Jr, Steven K Clinton, Tomatoes, Lycopene, and Prostate Cancer: What Have We Learned from Experimental Models?, The Journal of Nutrition, Volume 152, Issue 6, June 2022, Pages 1381–1403, https://doi.org/10.1093/jn/nxac066.
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