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WELL-DONE RED MEAT DOES NOT APPEAR TO INCREASE RISK OF BREAST CANCER, UC IRVINE STUDY FINDS
Results Counter Previous Findings Showing Link Between Breast Cancer and Eating Fully Cooked Meats
Irvine, Calif. -- Eating well-done red meat prepared with such high-temperature cooking methods as grilling and frying does not appear to increase the risk of breast cancer, according to a UC Irvine College of Medicine study that also found that eating greater amounts of thoroughly cooked white meats such as chicken appears to protect against the disease.
The study counters previous findings that reported a link between breast cancer and eating well-done meats.
Dr. Ralph J. Delfino, assistant professor of epidemiology, and Hoda Anton-Culver, professor of epidemiology, led a research team that found that a gene suspected of metabolizing cancer-causing chemicals on the surface of well-done meats had no link to breast cancer. Women who ate well-done red meat such as pork or beef had no increased risk of breast cancer, and women who ate chicken had half the risk of breast cancer compared with women who did not eat as much white meat. The findings appear in the April issue of Carcinogenesis.
"No matter how the food was prepared--blackened, barbecued, grilled or pan-fried--red meat didn't increase the risk, and white meat actually seemed to offer protection against breast cancer," Delfino said. "Although previous studies showed chemicals found on the surface of these foods have caused mammary cell cancers in rats, we didn't see it happening in humans. However, this study cannot rule out that these foods may add to the risk of colon and stomach cancers."
The researchers compared the diets of 114 women with breast cancer with those of 280 women who had benign breast growths. They were questioned on their diet of red meat, which included hamburgers, beefsteak, pork chops, bacon and breakfast sausage. White meat eaten included chicken, turkey or fish (shellfish were not included).
The researchers looked for activity of a gene that produces an enzyme in the blood known as NAT2. In previous studies involving rats, this NAT2 enzyme activated cancer-causing chemicals that are produced on the surface of meats by high-temperature cooking methods such as grilling and frying. The NAT2 enzyme helped the cancer-causing chemicals--called heterocyclic aromatic amines--bind to DNA, a process that induced cancer in rats.
However, in the UCI study, levels of the NAT2 enzyme were no different among women with breast cancer than among women with benign growths--regardless of the types of red meat consumed.
Women who ate more than 67 grams of white meat daily, however, had half the risk of breast cancer compared to women eating one-third that amount, less than 26 grams a day. This effect was seen even among women who ate pan-fried or barbecued chicken, which are known to have high amounts of heterocyclic aromatic amines. It was not clear from the study what may be causing this protective effect.
"Our study shows that the causes of cancer are often much more complex than they may appear from animal studies. We have to be very cautious in interpreting these results, since our study included a small number of participants," Anton-Culver said. "We need to expand this investigation to compare our findings with those of women who are free of any breast disease."
The researchers are now looking at other genes that may play a role in metabolism and either increase or decrease the risks of getting cancer. The research was conducted through the UCI Center for Cancer Genetics Research and Prevention, which is directed by Anton-Culver. The research was funded by the University of California Breast Cancer Research Program.
The Center for Cancer Genetics Research and Prevention is part of UCI's Biomedical Research Center, located on the western campus in the College of Medicine. The research center is providing much-needed laboratory and clinical facilities for UCI researchers focusing on the major health challenges of the 21st century. When complete, the center will focus on research in the neurosciences, the genetics of cancer, immunology and infectious disease and clinical trials. The center's first building, the Gillespie Neuroscience Research Facility, is home to the Reeve-Irvine Research Center and the Institute for Brain Aging and Dementia. Construction of the second building, the Robert R. Sprague Family Foundation Hall, began in February.
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Contact: Andrew Porterfield
(949) 824-3969
[email protected]
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