What's in the Beef?

Genetically engineered growth hormones are commonly used in beef production. The hormones have been Food and Drug Administration (FDA) approved since the 1950s, but are now produced using genetic engineering techniques. The United States Department of Agriculture (USDA) says the use of the hormones creates a more flavorful and more tender product at lower costs to cattle producers, the environment, and consumers.

There are six approved growth hormones that are produced using genetic engineering: estradiol, progesterone, testosterone, zeranol, melengestrol acetate, and trenbolone acetate. The first three hormones occur in both humans and animals. The other three substances are artificial hormones designed to act like the natural hormones.

There is concern by some researchers and consumers that these hormones may cause cancer, hormonal imbalance, developmental and immune risks in humans who eat these growth hormones.