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 *********************************************** The LACTNET mailing list is powered by L-Soft's renowned LISTSERV(R) list management software together with L-Soft's LSMTP(TM) mailer for lightning fast mail delivery. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html