Researchers Look At Cattle Growth Hormone and Breast Cancer
By Rachael Myers Lowe, cancerpage.com
(October 15, 2002) - Researchers at Ohio State University’s Comprehensive Cancer Center are investigating whether a drug used widely in the beef industry to promote weight gain may affect breast cancer risk in human consumers of treated beef.
Zeranol is a synthetic non-steroidal estrogenic growth promoter. Manufactured as a pellet, it is implanted in the ear of cattle to bulk them up for slaughter.
The question is, does the drug remain in meat products consumed by humans in concentrations sufficient to mimic the effects of estrogen in humans?And if it does, is health compromised?
Some breast cancers grow more when exposed to estrogen. There is a body of scientific evidence that suggests lifetime exposure to estrogen affects a woman’s risk of breast cancer. It is thought that the longer the exposure to high levels of the hormone, the greater the breast cancer risk.
Young C. Lin, D.V.M., of Ohio State University and colleagues want to find out whether long-term low-level exposure to zeranol might add to that risk too.
Preliminary lab tests by Lin, a professor of veterinary medicine, have already demonstrated that the blood and meat of zeranol implanted beef cattle “can alter the expression of estrogen-regulated genes in cultured normal and cancerous human breast cells and in the human breast cancer cell line, MCF-7.” These effects were noticed even at zeranol concentrations much lower than currently allowed by the Food and Drug Administration.
Researchers are now moving the research into human subjects by examining normal and breast cancer tissues taken from patients at the James Cancer Hospital in Columbus, Ohio.
Participants will be asked to fill out a questionnaire about their beef consumption habits. Blood and urine samples will be examined to measure residual zeranol levels and compare those levels to activity of several biomarkers associated with breast cancer.
At the same time, Lin and colleagues in Minnesota, New Jersey, Texas, California and Ohio will collect and test random samples of store-bought beef products for residual zeranol levels to see how prevalent the drug is in commercially available products.
Lin says it’s much too soon to draw any conclusions about the effects of zeronal on humans.
No link between zeranol and breast cancer has been established, he points out. “We have no proof, and we are thoroughly neutral on the matter…We are merely raising a question based on evidence,” Lin said a year ago when the government grant was announced.
Lin’s three-year study, funded by the National Cancer Institute, was launched last year. It is designed to clarify the potential role of zeranol exposure in breast cancer, identify potentially valuable biomaker tools for assessing zeranol exposure in breast cancer, and finally, offer federal regulators information they need when considering future regulation of the use of growth promoters like zeranol in beef raised for human consumption.
Because so many cases of breast cancer cannot be explained by known risk factors, the impact of environmental factors has been an area of intense interest in the scientific community.
Zeranol and other growth hormones have been used in cattle for decades. Because zeranol is not metabolized as quickly as naturally occurring steroid hormones, the federal government required more stringent testing before it was approved for use. Manufacturers had to demonstrate that the amount of hormone “left in edible tissue after treatment is below the appropriate safe level.” The FDA currently allows zeranol intake of 00125 milligrams per kilogram of body weight per day.
Manufactured by Schering-Plough Animal Health Corp in Union, NJ, zeranol is sold under the brand name Ralgro.
Source: Organic Consumers Org
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