By DAVID WILLIAMSON
UNC-CH News Services
(Embargoed) CHAPEL HILL -- People looking for a good guilt-free reason to eat pizza might relish results of a major study that took place in nine European countries.
The study involved analyzing fat samples taken from 1,379 men who suffered heart attacks and comparing them with fat samples from healthy control subjects. Researchers found that an antioxidant compound called lycopene appeared to have a protective effect against heart attacks.
The chief source of lycopene in the average diet is tomato sauce, and the food many Americans get most of their tomato sauce from is pizza.
"Based on our findings, and other research showing lycopene can be an excellent antioxidant, we recommend that people eat tomato-based cooked foods," said Dr. Lenore Kohlmeier, professor of nutrition and epidemiology at the University of North Carolina at Chapel Hill schools of public health and medicine. "Tomato sauce on grains or pasta would be better than pizza, however, because cheese can carry a lot of fat."
The apparent protective effect of lycopene -- or another unknown nutrient closely associated with it -- was greatest among non-smokers, the study showed.
A report on the research appears in the Oct. 15 issue of the American Journal of Epidemiology. Kohlmeier, a member of the UNC Lineberger Comprehensive Cancer Center, is chief author.
Researchers found that men whose fat samples revealed high consumption of lycopene had about half the risk of heart attack as men whose samples showed low lycopene consumption. This effect exceeded any protective effect of either alpha- or beta-carotene -- dietary carotenoid compounds similar to lycopene.
Other foods containing lycopene are watermelon, red grapefruit and, to a lesser extent, shellfish, Kohlmeier said. People get more lycopene from cooked tomatoes than raw ones; apparently cooking releases the nutrient from the matrix that binds it in raw tomatoes. The process appears to be similar to the way cooking releases beta-carotene from raw carrots.
"Again we are seeing that consuming protective substances through food is much better and safer than turning to a supplement," the scientist said. "In fact, supplements may actually compete with and inhibit uptake of other important products in our diet."
The study took place in Finland, Germany, Israel, the Netherlands, Norway, Russia, Scotland, Spain and Switzerland and was part of the European Community Multicenter Study on Antioxidants, Myocardial Infarction and Breast Cancer (EURAMIC). It was financed by participating countries in part as a Concerted Action by the Commission of European Communities.
Co-authors of the new report include Drs. Jeremy D. Kark, Enrique Gomez-Garcia, Blaise C. Martin, Susan E. Steck, Alwine F.M. Kardinaal, Jetmund Ringstad, Michael Thamm, Victor Masaev, Rudolf Riemersma, Jose M. Martin-Moreno, Jussi K. Huttunen and Frans J. Kok.
Antioxidants are compounds that are believed to help protect the body against damage caused by charged particles of oxygen known as free radicals, Kohlmeier said. Such oxidative processes occur naturally, but external stresses such as cigarette smoking and sun exposure add to them and can increase damage to cell membranes and body proteins. Many scientists around the world are trying to identify antioxidants and understand how they work.
Low density lipoproteins, a form of cholesterol that circulates in blood, are believed to be particularly dangerous in promoting heart disease through oxidation, she said. Lycopene -- or an unknown, closely associated compound -- may prevent their formation in the blood. Another recent study suggested lycopene-rich foods might protect against prostate cancer.
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Note: Kohlmeier can be reached at (919) 966-7450.
Contact: David Williamson
Journal
American Journal of Epidemiology