Cancer
Thirteen (13) cancer types were identified in the collection of original research articles (n=178) meeting criteria for this review. Among the 13 cancer types, breast, colorectal, gastric/upper gastrointestinal, and prostate cancer have the most original research published in humans related to tomato / lycopene intake ranging from 17 to 60 publications. For breast, colorectal and gastric cancers, the data support a neutral, although potentially protective, relationship between tomato/lycopene intake and disease risk. Conclusions reflect outcomes from observational investigations on the association between dietary and plasma/serum lycopene and disease risk. Few investigations are available on tomato / tomato-based foods intake and cancer risk, suggesting an area for future research. Of note, for gastric and lung cancer, the protective association is strongest with tomato/tomato-based foods intake and less support is apparent with dietary lycopene intake.
Prostate cancer (n=60) with substantial attention in each of the 4 research subcategories (dietary lycopene, plasma/serum lycopene, tomato/tomato-based foods intake and supplementation) has the most complete dataset to draw conclusions. Investigations range in quality; however, overall, the data support a protective relationship between consumption of tomato/tomato-based foods and lower risk for prostate cancer. Reports on lycopene supplementation in patients with prostate cancer indicate that lycopene supplementation is safe and well tolerated for up to 1 year, but does not improve disease status, as measured by changes in PSA levels. Previous reports indicating a benefit of lycopene supplementation in prostate cancer disease progression may be an artifact of transient endpoints, of which PSA is considered by some organizations. Data continue to support the need to investigate the effects of potential foods or bioactive components of foods for longer durations and in more people to more fully understand the potential of their action.
