"...the abnormalities in rBGH milk also include excess levels of the natural insulin-like growth factor-1 (IGF-1) in rBGH milk, with increases ranging up to 20-fold. Based on six unpublished industry studies, FDA admitted that IGF-1 levels in rBGH milk were consistently and statistically increased, and that they were further increased by pasteurization. These increases were also admitted by Eli Lilly Industries in their application for marketing authorization in the European Community. It should also be noted that pasteurization of milk increases its IGF-1 levels by a further 70 percent.
IGF-1 is a protein fraction known as a peptide. As such, it survives digestion and is readily absorbed into the blood. It has been shown to have marked growth promoting effects following short-term feeding tests in rats. Most importantly, increased IGF-1 levels have been reported to increase risks of breast cancer by seven times in 19 scientific publications, colon cancer by five times in 19 publications, and prostate cancer by up to 5 percent in six publications."