Hormones are naturally occuring chemicals found all animals. They control important body functions, such as growth and reproduction. In the meat industry, six synthetic hormones are currently approved by the US Food and Drug Administration (FDA) for use in US livestock to speed lean muscle growth. Three of the approved additives are synthetic versions of naturally-occurring hormones in humans and animals: estrogen, testosterone, and progesterone and the others are synthetic variations that mimic these. These artificial hormones, which are injected into 90% of US livestock, increase the production of beef and veal by up to 15% by making young animals gain wait faster. In the dairy industry, the genetically-engineered additive recumbent bovine growth hormone (rbGH) is approved by the FDA. It is injected into one-third of all US cows and increases milk production by 10%.
Although hormones are essential for development of healthy tissues, synthetic steroid hormones used in pharmaceutical drugs have been found to increase cancer risk, raising a question of safety of these additives being injected into our food. On the one hand, the FDA has repeatedly declared that there is no difference between cows treated with hormones and those that are not. They claim that the additives are negligible in comparison to levels that occur naturally in both cows and humans. Dairy cows injected with rbGH have a higher concentration of this hormone in their milk, but sources report that it is not recognized as a hormone in the human body and so health risks are unlikely.
However, there is another body of scientific research that argues that consuming meat and dairy injected with artificial hormones imposes human health risks. In 2002, the European Union concluded, for the third time, that using hormones as growth promoters for cattle poses potential health risks for consumers based on a review of 17 studies along with recent scientific evidence. Europe and Canada both ban the use of artificial growth hormones. In addition, cows receiving rbGH have increased levels of insulin-like growth factor-1 (IGF-1) in their milk, and higher levels of this protein hormone is associated with breast, colon, and prostrate cancers. However, no research has been conducted to date to show that drinking milk with elevated levels of IGF-1 results in higher blood levels of the hormone in humans. In conclusion, there is currently not enough scientific information to completely support or refute the purported heath risks from consuming meat or dairy from hormonally treated cows.
For more information:
European Union, 2002: http://europa.eu.int/comm/food/fs/sc/scv/outcome_en.html
USDA/Food Safety and Inspection Service: http://www.fsis.usda.gov"
