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At various points during this series, I’ll post about issues surrounding food and agriculture to offer a more complete picture of the problems (and solutions) related to our current food system. Today, we’re going to talk about hormones.

We all have hormones – humans and all other animals. These chemicals are produced naturally in our bodies and circulate through our bloodstream to regulate and balance the work of our cells and organs. As far back as the 1930s, researchers noticed that cows injected with material from cow pituitary glands (a hormone-secreting organ) produced more milk. They also realized then that estrogen helped cattle and poultry grow faster. In the 1950s, a synthetic estrogen called DES was used to fatten cattle and chickens, then was phased out in the 1970s because it was found to cause cancer.

Today in the United States, cattle and dairy cows are still administered hormones to make them grow faster or produce more milk. In 2007, 34.3 million heads of cattle and 758,100 calves were slaughtered for beef in the United States, with approximately two-thirds having been regularly administered hormones either through an ear implant or in their feed. In addition, about one third of all dairy cows are routinely injected with rBGH, a genetically engineered hormone used to make cows produce more milk. Although the United States Department of Agriculture (USDA) and the Food and Drug Administration (FDA) state that these hormones are safe, there are continuing questions, growing concern and controversy about the routine use of added hormones in food animals.

There are six hormones administered to beef cattle (as well as sheep), three natural (estradiol, progesterone, and testosterone) and three synthetic (zeranol, trenbolone acetate, and melengestrol acetate). According to the European Union’s Scientific Committee on Veterinary Measures Relating to Public Health (SCVPH), when the naturally occurring hormones are given to cattle, their hormone levels increase 7 to 20 times. The SCVPH questioned whether hormone residues in meat from these animals can disrupt the hormone balance in humans, and concluded that “no acceptable daily intake could be established for any of these hormones.” They also concluded that people who eat meat with added hormones are at greater risk for certain cancers and some types of hormonal imbalances. As a result, the use of hormones to promote growth of farm animals has been prohibited by the European nations for more than two decades. Not so, however, in the United States.

Up to one third of all dairy cows in the U.S. are injected with a genetically engineered hormone called rBGH, or recombinant bovine growth hormone (also known as rBST or recombinant bovine somatotropin). (Some estimates have the figure down to about 17% now, in the face of widespread consumer protests.) rBGH is injected into dairy cows to make them produce more milk. The artificial hormone also makes cows more prone to illness, such as mastitis, a very painful udder infection that can lead to pus getting into milk, This increased risk of illness can lead to increased antibiotic use on cows treated with rBGH, resulting in more antibiotic residues in the milk we drink and dairy products we consume, potentially contributing to an increase of antibiotic-resistant bacteria.

rBGH was approved in the United States in 1993, but has been controversial ever since farmers started using it. The European Union, Japan, Australia and Canada have all outlawed its use.

The, small, weaker doses of antibiotics routinely given to farm animals allow stronger strains of bacteria to survive and develop immunity to that particular antibiotic. (That’s why when your doctor says to finish all your antibiotic medication, s/he means it! – it’s so no bacteria will survive in your system and develop an immunity to the medication.) The stronger bacterial strains that survive the low doses regularly given to farm animals pass on their antibiotic resistance to their offspring which, over time, can result in bacteria that can infect people or animals but that can no longer be treated with the antibiotic to which hey have developed resistance. As a result, medicines that were effective in the past in treating infections may be rendered useless, leaving people and animals at greater risk.

There is no conclusive evidence about the safety of rBGH on humans because no thorough studies have been undertaken. When approving the hormone, the FDA relied on one small, inconclusive study by Monsanto (the drug company that created rBGH) where 30 rats were given rBGH for 90 days. The study was never published, and when Health Canada discovered the results, they uncovered significant issues that should have resulted in a full review by the FDA. In August 2008, Monsanto sold their Posilac patent (their brand name for rBGH) to Eli Lilly & Company.

The Sprecher Institute for Comparative Cancer Research at Cornell University concluded that no determination can be made about possible human health effects until long-term studies are undertaken that compare people who eat meat and dairy products from hormone-treated animals with those who do not. In other words, they can’t conclude that meat and dairy from hormone-treated animals is safe until further studies are done. In addition, the institute found that no conclusion can be made about whether or not hormones in meat cause early puberty in girls. Further studies were recommended, as well as long-term studies on the effects of life-long exposure to milk from rBGH-treated cows to look for unexpected health effects of consuming dairy products from these cows.

In addition to possible effects on humans, there is growing concern about the environmental effects. Cows secrete undigested hormones in their manure, which is then applied to soil. These hormone residues can leak into the soil, as well as into surface and groundwater. Aquatic ecosystems are at risk, and the reproductive ability of fish has been shown to be affected by hormone-polluted waters.

Despite these concerns and the inadequacies of studies, the United States permits growth hormones in cattle and dairy cows. The European Union does not allow any use of hormones and, since 1998, has banned the import of beef or dairy raised on hormones.

What can you do?

If you’re concerned about the possibility of added hormones in your beef or dairy products, you can:

• Use the Eat Well Guide to find farms, stores and restaurants that serve food from animals raised without added hormones.
• Find a local farmer and ask whether their animals are raised with any added hormones or growth enhancers. Farmers’ markets are a great place to find farmers who are willing to talk about how their products are raised. Or use the Eat Well Guide to find a farm near you. If you’re still having trouble, try Local Harvest, where you can not only find local farmers, you can buy directly through them.
• Because added hormones are banned in the European Union, any products raised there will be added-hormone free. That’s not exactly a choice that promotes eating local, but the bottom line with sustainable food is that you have to decide what’s best for you.
• Dairy products from Canada, the European Union, Japan and Australia will be rBGH-free.
• Cut back on the amount of meat and dairy you eat – the less of it you eat, the less chance of hormone residue or other possible complications.

Next week, we’ll continue with how to shop for sustainable food. Until then, happy Memorial Day!

(Diane Hatz is the Founder of Sustainable Table, Executive Producer of The Meatrix movies and co-Founder of the Eat Well Guide. This is the tenth installment in her series Guide to Good Food.)

Change Food® works toward a healthier food system for people, animals & the planet.  Learn more about Plant Eat Share – planting food in public spaces. For free.