Kathleen wrote:

"A mom wishes to know if mixing formula with breastmilk will inactivate some
of the consituents of breastmilk."

I believe the answer is yes:

"The effect of nutritional additives on anti-infective factors in human
milk."  Quan R et al.  Clin Pediatr (Phila) 1994 Jun; 33(6): 325-8.

The abstract for this article can be found at:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_ui
ds=8200164&dopt=Abstract

It states, in part:

"Significant decreases (41% to 74%) in lysozyme activity were seen with the
addition of all formulas; breast-milk fortifier reduced activity by 19%,
while no differences were seen with Moducal, sterile water, or Poly-Vi-Sol.
No differences were seen in total IgA content, but some decreases were seen
in specific IgA to E. coli serotypes 04 and 06. E. coli growth was
determined after 3 1/2 hours of incubation at 37 degrees C after mixing. All
cow-milk formulas enhanced E. coli growth; soy formulas and other additives
preserved inhibition of bacterial growth. Nutritional additives can impair
anti-infective properties of human milk, and such interplay should be
considered in the decision on the feeding regimen of premature infants."

On a similar topic, see:

 Pediatrics 1997 Aug;100(2 Pt 1):240-3

"The effects of nutrient fortification and varying storage conditions on
host defense properties of human milk."

Jocson MA, Mason EO, Schanler RJ.

viewable at:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_ui
ds=9240806&dopt=Abstract

Barb Strange

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