Most milk from cows given growth hormones contains recombinant bovine growth hormone. RBGH is given to cows to increase milk production, which helps meet consumer demand for the beverage, as well as helps maximize profits for dairy farmers. While this benefits the farmers bottom line, rBGH may be harmful to the consumer.
The use of growth hormones can increase the risk that milk cows get infections. For example, many milk cows given growth hormones develop mastitis, an infection of the mammary gland, according to the American Cancer Society. To combat the infections, many dairy farmers give antibiotics to cows, and these end up in the milk supply. When humans consume the milk and the antibiotic residue, it can cause their bodies to build up a resistance to antibiotics, rendering them useless should a human come down with a bacterial infection, according to the Nutrition Digest website. The antibacterial residue can also cause allergic reactions for certain people drinking the milk.
Growth Hormones and Cancer Risk
Milk from cows given rBGH has higher levels of insulinlike growth factor-1. IFG-1 is a hormone that helps cells grow, but it can also increase the risk of cancerous cells forming, according to the American Cancer Society. High levels of IFG-1 in the human body might raise the risk of certain types of cancers, such as breast, prostate and colon. This occurs because high levels of IFG-1 inhibit the human body's natural ability to destroy microscopic cancers before they cause a problem, according to "Nutrition Digest," a publication from the American Nutrition Association.
Unstudied Health Problems
The long-term effects of exposure to growth hormones, most notably rBGH, are largely unknown, according to the American Cancer Society. For example, it isn't known if IGF-1 stays in the body or for how long. It's also unknown what the long-term consequences might be if IGF-1 does stay in the body for long periods of time. More research is necessary to determine the long-term effects of drinking milk with rBGH, the American Cancer Society notes.
Effects on the Cows
To help spare animals of potential suffering, you may want to avoid drinking milk from cows given growth hormones and choose more humanely produced animal foods. Cows given rBGH are 50 percent more likely to have hoof and leg problems, including lameness, according to the Humane Society of the United States. Other side effects include reproductive problems and infections.