Can cows milk protein pass into human breast milk?
The old and traditional way of (scientific) thinking that proteins are broken down in our intestines into individual amino acids which are then passed into the blood stream seems not to be true anymore. I recall the current hype about gluten intolerance and the leaky gut syndrome, causing all sorts of problems by allowing substances passing the otherwise selective gut barrier and triggering various responses in the body. The gut permeability has been a subject of an extensive research recently. Also the micro-RNA concept, which I encountered a couple of years ago in connection with the GMO produce and its risks, sounded strange, but not impossible. However, reading such information that the cows milk protein could make its way into human breast milk and sucked unchanged by the baby, was new to me.
Nonetheless, back in 2012 the scientists were still not decided whether it is true or not. They hypothesize that the beta-lactoglobulin, relatively complex protein in cows milk comprised of 162 amino acids, could be passed from food into the mother’s breast milk and cause allergic reaction in breastfed children who have predisposition for this allergy. In order to avoid that, those mothers are advised to stay off dairy products while breastfeeding their allergic child. However, avoiding dairy it is not recommended for pregnant or breastfeeding mothers without the allergic child, exactly for the reason to reduce the risk such allergy in future.
If the mother cannot breastfeed (for whatever reason).
If you thought, or were advised, to switch from the usual to soy formula, beware also. About 30-50% infants with dairy allergy are also allergic to soy protein. There are infant formulas called Extensively hydrolyzed formula, in which the proteins have already been partially digested into smaller chains of amino acids, hence unlikely triggering immune response.
Note: This article was just informational and was not intended to promote infant formula whatsoever.
Breast is best.