Q: Someone told me that eating tomato ketchup could actually reduce risk of certain cancers. Is this true and, if so, how much do I need to consume?
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ary Alice Gettings and Cindy Javor are registered dietitians for Penn State Cooperative Extension. Their column appears every other Thursday in PG Food. If you have a question about nutrition or food safety, call 724-774-3003 in Beaver County or 412-473-2540 in Allegheny County. Hours are 8:30 a.m. to 4:30 p.m. Monday through Friday.
Lycopene chart
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A: Tomatoes are the second- most-consumed vegetable in North America. Lately, the tomato's vibrant red color has been making the news. The newsmaker is actually a pigment called lycopene, which provides some foods with their red color. The more red the tomato, the higher the level of lycopene. While the information you received about ketchup is true, it's not the only food that helps fight cancer.
You may have heard of a group of phytochemicals called carotenoids. One of the better-known carotenoids is beta-carotene. Lycopene is one of the most powerful antioxidants in the carotenoid group and helps ward off the damaging effects of free radicals. When free radicals in your body combine with oxygen, they create havoc in your body and are responsible for many diseases and the effects of aging. Lycopene acts as an antioxidant by not allowing free radicals to combine with oxygen, thus preventing damage to healthy cells and reducing the risk of cancer and other diseases.
Over the last several years, many food and nutrition scientists have published studies showing that consuming lycopene may help reduce the risk of prostate cancer, cervical cancer and other diseases. For example, a human study conducted by the University of Toronto on dietary lycopene confirmed that as lycopene levels in the blood go up, the levels of oxidized compounds, such as free radicals, go down. Some organs, such as the prostate, liver, adrenal gland and testes, have been shown to contain much higher levels of lycopene. This suggests that there may be a specialized way to transport lycopene into these organs and that these organs may be more susceptible to cancer if this antioxidant is not present in sufficient quantities.
A study of 48,000 men, conducted by Harvard Medical School, showed that consuming tomato products twice a week, as opposed to never, was associated with a reduced risk of prostate cancer of up to 34 percent. Animal studies also have demonstrated that the presence of lycopene in the diet can prevent cancer.
Intuition might sway you to believe that garden-fresh tomatoes are the most healthful, but this is not so when it comes to ingesting lycopene. Tomato products containing fat allow more lycopene to be absorbed by the body as compared to those without fat. At this time, there is no recommended daily allowance for lycopene, nor has any government agency or food industry association made claims about appropriate portion size. But, recommendations by registered dietitians to eat three to five servings of vegetables and two to four servings of fruits daily remain the same. To increase your intake of lycopene, select processed tomato products with some added fat, such as tomato juice, sauce, paste and even ketchup, as part of your vegetable servings.
Another recent study evaluated the effect of eating various levels of lycopene and its absorption and antioxidant properties. A tablespoon of ketchup, for example, supplies 2.7 milligrams of lycopene. Lycopene levels of 5, 10, and 20 milligrams were consumed by healthy people in the form of ketchup for a two-week period. The study revealed that at all three levels there was a significant increase in serum lycopene levels and a reduction in free radical oxidation. The bottom line: It doesn't take much lycopene to fight off disease.
If you would like more detailed information about lycopene from the Heinz Institute of Nutritional Sciences, go to www.lycopene.org.
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