The Humulin insulin we use is from E. coli bacteria.
http://www.littletree.com.au/dna.htm
This is ironic because there is anecdotal and statistical correlation between babies fed cows milk and insulin dependent diabetes.
My mother and grandmother had what was then called juvenile diabetes. Grandmother was adopted. My mothers older siblings, my aunt and uncle were not diabetic.They were breast fed. My Mom was bottle fed.
…Studies comparing diabetes with the general population have shown a statistical correlation between young children drinking milk and the later onset of insulin-dependent diabetes. Further studies are needed, but researchers speculate that the early introduction of cow's milk may cause an immune reaction in the body. By some biochemical quirk, the protein in cow's milk (bovine serum albumin) is similar to the natural proteins in the pancreas, the organ that manufactures insulin. Researchers theorize that some people produce antibodies in reaction to cow's milk protein that attach themselves to the insulin- producing cells in the pancreas, eventually destroying them and leading to diabetes. In one statistical study, insulin-dependent children had elevated levels of anti-bovine serum albumin antibodies, but the control children only had a small amount of these antibodies in their blood.
It's prudent to delay the introduction of cow's milk to breastfed infants and children in the following situations:
• a strong family history of milk allergies
• a strong family history of Type I (insulin-dependent or juvenile onset) diabetes
• any indications the child may have milk allergies …
http://www.askdrsears.com/html/3/T032100.asp