I have a question about the Dangers of Dairy article by Paul Eastwood. How does IGF-1 (Insulin-like Growth Factor-1) enter the body when taken orally? Wouldn’t it be broken down into amino acids and di +tri-peptides like all other proteins? If IGF-1 could be delivered intact orally, wouldn’t drug companies use this as a method of delivery (same goes for growth hormone)??
I’m afraid IGF-1 survives absorption into the bloodstream. I believe the latest research shows that casein (the main protein in cow’s milk) has a protective role on IGF-1. This research was based on the fact that another growth hormone, Epidermal Growth Factor (EGF), in the presence of casein survived degradation by the digestive system.
Below is also a quote from an FDA website (http://www.igf-1-and-milk.com/igf-1-and-milk-statement-from-fda) on this topic:
“In evaluating the potential for human health risk from a natural component of the body, one can examine the effect of an increased exposure to IGF-I by employing several assumptions (i.e., IGF-I levels in milk from rbGH-treated cows are increased from 4 ng/ml to 6 ng/ml, all of the IGF-I in milk is absorbed into the body, and absorbed IGF-I is confined to the vascular compartment).”
- C. Xian. Degradation of IGF-1 in the adult rat gastrointestinal tract is limited by a specific antiserum or the dietary protein casein. Journal of endocrinology. Vol 146: No. 2 (Aug 1st 1995) pg 215
- W. Thornburg et al. Gastrointestinal absorption of epidermal growth factor in suckling rats. American Journal of Physiology. Vol 246: (1984) pgs G80-G85