As the name states, MSPI (milk-soy protein intolerance) is an intolerance to proteins found in certain foods – namely dairy and soy.
When embarking on an elimination diets, Moms are generally advised that it is safe to eat foods that contain soy oil and soy lecithin – two fats derived from soya beans. This makes going on the elimination diet easier, since many prepared foods contain these products. In principle, these fats are highly refined and do not contain any of the offending proteins that would irritate a MSPI child’s GI tract. In practice however, this is not always the case. Many MSPI Moms find that they need to eliminate soy lecithin and oil from their diet in order to resolve their child’s issues. The dietician following us at the Montreal Children’s Hospital, made it clear that this was far from a rare occurance. Our pediatrician even told us of a Mom who resolved her child’s intestinal bleeding only after eliminating her chewing gum, which contained soy lecithin.
My feeling on the subject is that it likely has to do with the quality of the ingredients used in prepared foods. If the lecithin or oil is not sufficiently refined, traces of offending protein will remain. Even a fragment of undigested protein in Mom’s breastmilk can be enough to irrate a sensitive child.
What does this mean for a new Mom going on an elimination diet? The general recommendation seems to be that soy oil and soy lecithin can remain in her diet initially. If the child’s MSPI symptoms are not resolved after two weeks or so (the time it takes for offending proteins to be completely removed from breastmilk), then eliminate soy oil and soy lecithin.
Soy lecithin has also proved problematic for parents who are formula feeding their MSPI child. It appears as though both Nutramigen and Alimentum contain soy lecithin, which means that some sensitive children will have to be fed Neocate.
See also : Soy Allergy (Wikipedia)