Cancer Researchers Keen on Tomatoes

Tomato-Derived Lycopene Showing Promise in Early Studies

Medically Reviewed by Charlotte E. Grayson Mathis, MD on November 11, 2002
From the WebMD Archives

Nov. 11, 2002 -- Tomatoes are quickly becoming the apple of many a cancer researcher's eye. Several studies presented at a recent cancer conference show a substance found in tomatoes called lycopene may prevent as well as treat several types of cancer.

Researchers think most of lycopene's anticancer benefits stem from its effects on a substance known as insulin-like growth factor (IGF). Recent research has suggested that the level of IGF in a person's blood can be a strong predictor of prostate or breast cancer risk, but until now the relationship between lycopene, IGF, and cancer risk wasn't clear.

In a study presented last month at the American Association for Cancer Research (AACR), Israeli researchers found that taking a supplement of lycopene effectively reduced IGF levels in the blood by more than 10% in 15 of the 28 men that received a twice-daily supplement for three to four weeks.

Study author Joseph Levy, MD, of Ben-Gurion University in Beer-Sheva, Israel, and colleagues also found that lycopene markedly reduced the growth of breast cancer cells in a laboratory test (not in humans). The substance also seemed to interfere with a number of other processes associated with cancer growth.

Another study presented at the conference by Levy suggests that lycopene may lessen the potential of plant-based estrogens (also called phytoestrogens) to increase breast cancer risk. Researchers say the findings are important because many women are turning to phytoestrogens, such as soy, as an alternative to estrogen-based hormone replacement therapies (HRT), which have been shown to slightly increase the risk of breast cancer.

The study found that lycopene inhibited the potentially harmful effects of genistein, a major component in soy, as well as IGF in breast cancer cells.

In addition, several other studies presented at the conference reveal that tomatoes might be showing up on a lot of cancer researcher's menus.

For example, a five-year Japanese study shows daily use of a supplement that contained a combination of natural tomato extract, beta-carotene, and vitamin E might be an effective way to reduce the risk of liver cancer in those at risk. Researchers found that patients who received the supplement had a 50% suppression of liver cancer.

Another study from Tufts University researchers found that taking a lycopene supplement may help protect against lung cancer by interfering with the body's processing of IGF. Their study found lycopene rapidly metabolized in the ferrets studied and may counter the effects of exposure to cigarette smoke.

SOURCE: American Association for Cancer Research meeting, Boston, October 2002.

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