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Genetically Engineered Growth Hormones in Meat

Jul 2, 2011 | By Helen Anderson
Genetically Engineered Growth Hormones in Meat
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Industrial cattle and sheep production in the United States relies heavily on the use of synthetic growth hormones to accelerate weight gain and increase milk production. This trend in animal husbandry has generated fierce debate over potential health hazards to both the animals and humans consuming hormone-treated products. Although the U.S. Department of Agriculture declares certain genetically modified growth hormones safe for use, health critics and consumer advocates warn that human exposure to growth hormones increases cancer risk and contributes to reproductive and endocrine disorders.

Background

Genetically modified, or synthetic, growth hormones stimulate rapid growth in cattle and sheep, causing animals to gain weight more quickly and thereby shortening the time between birth and slaughter. The FDA currently approves of six growth hormones for commercial use, and although legal limits exist to protect the health of the animals and consumers, according to the Cornell University Program on Breast Cancer and Environmental Risk, measuring hormone use is not always possible. Concerns surrounding the health risk of genetically modified hormones emerged in the 1970s with the discovery that the growth hormone DES contributed to breast cancer. Although DES has since been banned from use, concerns remain over the possible linkages between high hormone exposure, cancer risk and endocrine health.

Cancer Risk

Genetically modified growth hormones in meat may contribute to increased incidence of breast and other cancers. According to Dr. Samuel Epstein, professor of Environmental and Occupational Medicine at the University of Illinois School of Public Health and chairman of the Cancer Prevention Coalition, hormonally related cancers have increased significantly since 1975. Rates of breast cancer have risen by 10 percent, and testicular cancer has increased by 59 percent. Epstein maintains that meat hormones directly affect cancer incidence, and calls attention to data indicating that American women experience a breast cancer risk five times that of women in countries that do not allow the sale of hormone-treated meat.

Early Menstruation

Menarche, or the age at which a girl begins to menstruate, has been declining in the United States since the beginning of the 20th century due to improved nutrition status and increased fat and protein consumption. Early puberty results in prolonged exposure to sex hormones and is linked to increased breast cancer risk and possible reproductive disorders. Hormonal exposure through food may contribute to population-based trends in early puberty, but as of 2011, no epidemiological studies have been conducted to validate this association. However, existing research indicates two simultaneous trends -- one is the decrease in average age at menarche, and the other is the rise in consumption of hormone-treated meat and dairy products.

Global Concerns

While existing research in the United States does not indicate clear risks to human health from genetically modified growth hormones, the state of contemporary knowledge is limited by an absence of large-scale studies. However, different countries uphold different safety standards. Since 1989, the European Community, now European Union, has upheld a ban on all meat treated with artificial steroid hormones due to concerns about health risks that European scientists have validated. The EU and Canada also maintain a safety ban on the genetically modified hormone rbGH, which is in widespread use in the U.S.

References

Article reviewed by Christine Brncik Last updated on: Jul 2, 2011

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