Tomatoes as Disease Fighters:
Research in Progress








TOMATO 101 - Health Information and Research





The remarkable tomato nutrition story is full of technical terms. Refer to the accompanying glossary for an explanation of terms that may be unfamiliar.

Throughout the 1980's and early 90's, most of the attention
concerning carotenoids as cancer-fighters centered around
beta-carotene. The results were promising at first, but
gradually it became clear that with the more than 500
carotenoids found in plants, the picture was much more
complex. Just as the role of beta-carotene in cancer
fighting was called into serious question; the carotenoid
lycopene became the rising star. Lycopene, one of nature's
most powerful antioxidants, is found almost exclusively in
tomatoes. Following is a summary of the promising
lycopene research conducted during the past few years.

Lycopene entered the spotlight in 1995 with published studies from Harvard University identifying a positive association between intake of tomatoes and tomato-based foods and diminished risk of prostate cancer in a group of 48,000 health professionals followed over a six-year period. Their findings suggested that the antioxidant lycopene, present in high concentration in tomatoes, was a protection against prostate cancer. Furthermore, they found that other dietary antioxidants, including beta-carotene, were unrelated to prostate cancer risk reduction. In a similar observational study in Italy, where tomatoes are a mainstay of the diet, it was found that tomatoes had been consumed in significantly lower quantities by a group of subjects suffering from colorectal and other digestive tract cancers than by the healthy control group.

Laboratory studies in Israel suggest that lycopene may protect against additional types of cancer. Researchers at Ben-Gurion University in Israel found significantly fewer mammary tumors in rats receiving a tomato-based, lycopene-enriched supplement, whereas those receiving additional beta-carotene showed no protection against the development of mammary cancer.

In addition, in vitro (test tube) studies showed that lycopene significantly inhibited the growth of human endometrial, mammary and lung cancer cells. Lycopene was also found to suppress in vitro the effects of cancer-causing agents found in broiled or grilled meats.

There may also be an association between heart health and tomatoes. In a study conducted by University of North Carolina scientists, the fat samples drawn from both heart attack sufferers and healthy controls were analyzed for lycopene and other carotenoids. They found significantly more lycopene in the fat of the controls than the heart patients. Not surprisingly, the diet of the control group was also higher in tomato products leading the researchers to conclude that a lycopene-rich diet may have protected them against heart disease. A second study is underway to determine whether lycopene might also protect against oxidative damage to lung tissue that leads to cancer.

The method of preparing tomatoes seems to have an affect on lycopene absorption. In a study in Dusseldorf, Germany, researchers found that the lycopene blood levels were higher in subjects after ingestion of a heat-processed tomato product than when uncooked tomatoes were consumed. Apparently the heat disrupts the cell structure of the tomato, making lycopene more readily available. Adding a small amount of fat during the preparation of a tomato dish seems also to be beneficial. The fat "dissolves" lycopene, allowing more of it to be absorbed into the bloodstream. This supports the findings of the Harvard studies where consumption of heated tomato products seemed to correlate better with reduced risk of prostate cancer than did uncooked tomatoes and tomato juice.

At a recent symposium on lycopenes in New York City, several speakers cautioned against extracting lycopene or any other compound from tomatoes and administering it separately to obtain the benefits. Tomatoes are also a rich source of vitamins, mineral, carotenoids, and other phytochemicals that are most likely working together to help protect against cancer and other degenerative diseases.


REFERENCES: Franchesi, S. et al. Intern. J. Cancer 59:181, 1994 Giovanucci, E. et al. J. Natl Cancer Inst., 87:23. 1995 J. Levy, et al. Nutr. Cancer 24:257, 1995 Kohlmeier, L. et al. Am J. Epidemiol 146(8): 618, 1997 Gartner, C., W. Stahl and H. Sies. Am J Clin Nutr 66:116, 1997 Hoffmann, I. and J.H. Weisburger. Cancer Epidemiol, Biomarkers Prev 6(8): 643, 1997 2002 Florida Tomato Committee