The safety of hormones in food is still being debated, and there is no concrete evidence as to the harmful effects hormones may have; but this does not counter the concerns raised about ingesting them. There are FDA-approved chemicals and hormones being used today in meat and dairy production. A genetically engineered growth hormone is approved for use in cattle in the U.S. This hormone is injected into dairy cows to increase milk output. Cows treated with this hormone often require the use of antibiotics to treat infections. Consumer and health advocacy groups are concerned about potential risks that the use of hormones may cause in people, especially children. There are six approved hormones used to promote growth in cows, two of which may be carcinogens, and they are also produced naturally in the human body. These two sex hormones, estrogen and progesterone, are linked to several kinds of cancer. In addition to posing a risk for cancer, these sex hormones may also pose a risk for children, who have lower levels of these hormones in their bodies and even a slight increase may have health consequences. No growth hormones are approved for use in Canada and Europe because of the concerns for potential health risks in humans.
Girls are now starting puberty and getting their first periods at an earlier age, but no large-scale studies have been done on the effects of exposure to hormone residues in food. There is still concern that hormones used in meat and dairy production may be linked to early puberty and other health risks.