Is IGF-1 from rBGH treated milk absorbed by people who drink it?
Some studies have shown that adults who drink milk have approximately 10% higher levels of insulin-like growth factor (IGF-1) in the blood than those who drink little or no milk. But this same observation has been reported in people who drink soymilk. This suggests that this finding is not specific to cow milk, and may be caused by protein, minerals, or some other factor unrelated to rBGH. There have been no direct comparisons of IGF-1 levels in people who drink ordinary milk vs. milk stimulated by rBGH. Substantial evidence indicates that IGF levels at the high end of the normal range may influence the development of certain tumors. Normal and cancerous cells from a variety of tissues have IGF receptors on their surface. And high concentrations of IGF are known to stimulate growth. Several prospective studies found a relationship between circulating levels of IGF-1 and the development of prostate, breast, colorectal, and other cancers. But later studies have failed to confirm these re
