This is Your Beef on Drugs:
The Health and Environmental Risks of Hormones in Meat

Hormones in our food supply?
Since the early 1970s, hormones have been used extensively in the production of beef and milk in the United States , with hormone development research starting as far back as the 1950s[1].  As many as two-thirds of cattle raised in the U.S are treated with these hormones[2]. 

Although growing numbers of consumers and scientists have expressed concerns about potential human health risks of this practice, the USDA and FDA have approved the use of six hormone growth promotants (HGPs) in the cultivation of beef cattle, and one more hormone used to increase milk productivity[3][4].  Only a few other countries have approved the use of HGPs, while many others have banned their use.

The hormones are implanted or injected into cattle in various stages of maturity, but are not allowed in calves[5].  Hormones used in beef cattle include the male hormone testosterone and its synthetic equivalent trenbolone acetate, and the female hormone progesterone including three synthetic derivatives zeranol , 17 beta-estradiol, and melengestrol acetate (MGA). All HGPs are either implanted or injected into the cows except melengestrol which is a feed additive.  

Illegal Hormone Use in the Veal Industry
The veal industry has recently been found guilty of using banned hormones in growing up to 90% of its veal calves and this has reportedly been common practice for decades[6].  These hormones include all six HGPs approved for use in adult cattle, namely testosterone, progesterone, trenbolone acetate, 17 beta-estradiol, zeranol, and MGA but they have never been approved for calves⁴.  The safety or side effects of injecting calves with hormones intended for heifers and steers over 700 lbs has never been evaluated, but it is suspected that these hormones may be metabolized differently in the young calf’s body which could lead to greater amounts of hormones consumed by people who eat veal.⁵

Hormones and Cancer
The European Union (EU) has banned the importation of American and Canadian beef grown with the use any growth hormone, including 17 beta-estradiol because studies have shown that it is a “complete carcinogen.”[7]  This synthetic form of progesterone shares similar characteristics with a class of other molecules called endocrine disruptors that imitate other human hormones in the body and have been linked to diseases such as cancer.  Zeranol, another progesterone-imitator, has also been linked to cancer in a recent study done at Ohio State University .  Scientists exposed breast cancer cells to zeranol-treated beef.  The results indicated significant increases in cancer growth – some showed an increase even with zeranol levels 30 times below the level the FDA considers safe[8].  It should also be noted that the FDA does not permit any residual MGA to show up in beef residue testing[9].  It is considered a suspected carcinogen by the USDA[10].

Hormones in the Environment
With tons of hormones injected into beef and veal cattle, many of these hormones end up in farm run-off in the form of solid and liquid waste.  Sanitary waste treatment is seldom found on factory farms, and many farms simply have waste settling ponds that are easily flooded.  Hormones can then flow into nearby rivers and streams, as well as underground aquifers, eventually ending up in drinking water.  Endocrine-disruptor expert Ana Soto concluded that hormone levels in water run-off found in one downstream study “would be sufficient to produce a significant effect on target cells” and her study’s findings “point to the need to take steps to curtail environmental degradation caused by the release of these chemicals into bodies of water[11].”  A study done by a EPA fresh-water research facility in Duluth, MN found that female fish exposed to trenbolone in water developed bumps on their heads normally only witnessed in male fish when their natural testosterone levels were elevated.  There was a general pattern where female fish were slightly masculinized and male fish slightly feminized by trenbolone exposure[12]. 

The reproductive impacts observed in fish raise concerns that hormones used in beef and consumed by people might be a factor in rising incidence of premature development in girls[13] and lower sperm counts in men[14].

Conclusion
Given the potential of growth hormones to act as carcinogens and as reproductive toxins, combined with the demonstrated downstream effects of hormone run-off from feed lots, Friends of the Earth recommends that people seek organic or hormone-free beef, or beef alternatives. These are the surest ways of avoiding consuming unwanted additives in your beef.  Locations of providers of free-range, organic meats may be found at the website, www.eatwellguide.org, or at many local natural food stores or cooperatives.

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[1] “A Primer on Beef Hormones.” USDA-FAS.  http://www.fas.usda.gov/itp/policy/hormone2.html