Summary
The available evidence shows that the use of rBGH can cause adverse health effects in cows. The evidence for potential harm to humans is inconclusive. It is not clear that drinking milk produced using rBGH significantly increases IGF-1 levels in humans or adds to the risk of developing cancer. More research is needed to help better address these concerns.
The increased use of antibiotics to treat rBGH-induced mastitis does promote the development of antibiotic-resistant bacteria, but the extent to which these are transmitted to humans is unclear.
The American Cancer Society (ACS) has no formal position regarding rBGH. Together with its advocacy affiliate, the ACS Cancer Action Network (ACS CAN), the Society supports open, fair and transparent regulatory oversight of products containing rBGH. The ACS also encourages continued and expanded scientific research and independent, credible assessment of potential relationships between the use of this substance in cows and human cancer risk. We support regulatory standards based on rigorous scientific evidence to minimize exposure to carcinogens, and we encourage the FDA to give the public information regarding known and suspected causes of cancer in the food system. The need for an effective FDA in ensuring the safety of our food supply, medicines, and consumer products has never been greater.