John2598
July 24th, 2009, 12:04 pm
This is a follow-up question to a previous question about IGF in fresh cheese and milk. In part your answer was this: "Insulin-like Growth Factor is a peptide hormone that is cleaved by the stomach's peptidases prior to absorption in the intestines. So, when you consume milk of any type, you're destroying any peptides that enter the stomach."
My question: I'm not sure I know how to put the above information in proper perspective. I've read in "Diet Evolution" that, "All mammals secrete IGF into their milk to make their offspring grow quickly." How does IGF provide rapid growth if it's destroyed in the stomach?
Greyclouds
July 24th, 2009, 12:57 pm
This is a follow-up question to a previous question about IGF in fresh cheese and milk. In part your answer was this: "Insulin-like Growth Factor is a peptide hormone that is cleaved by the stomach's peptidases prior to absorption in the intestines. So, when you consume milk of any type, you're destroying any peptides that enter the stomach."
My question: I'm not sure I know how to put the above information in proper perspective. I've read in "Diet Evolution" that, "All mammals secrete IGF into their milk to make their offspring grow quickly." How does IGF provide rapid growth if it's destroyed in the stomach?
This is an excellent question, and it has to do with the newly born infant's stomach/gut.
When an infant is born, the stomach mucosa and small intestinal mucosa are VERY poorly developed! This makes sense, especially when you consider the fact that the newborn NEVER used its stomach or intestines while in the womb!
It is believed that many proteins can pass through the very immature human gut, though the gut rapidly develops and will prevent such "leakage" at about 6 months post-partum.
For more information, see this pamphlet: http://www.igf-1-and-milk.com/PDF/American%20Cancer%20Society%20rbST.pdf
Other things that the infant derives from their mother's milk that will be eventually broken down by their mature stomach: Immune system antibodies. So, breast milk also provides these proteins that are a critical part of the infant's immune system! Like IGF, these proteins can pass through the IMMATURE stomach, but are blocked by a mature stomach!
The infant is biologically incomplete with respect to even a 2 year old human baby: the skull hasn't fully enclosed the brain, the heart still has a "hole" in the middle, and the digestive tract is completely immature with no nascent microbiota.