THE EFFECT OF NUTRITIONAL ADDITIVES ON ANTIINFECTIVE FACTORS IN HUMAN-MILK

It has become a common practice to supplement human milk with a variet y of additives to improve the nutritive content of the feeding for the premature infant. Twenty-two freshly frozen human milk samples were m easured for lysozyme activity, total IgA, and specific IgA to Escheric hia coli serotypes 01, 04, and 06. One mL aliquots were mixed with the following: 1 mL of Similac, Similac Special Care, Enfamil, Enfamil Pr emature Formula, and sterile water; 33 mL of Poly-Vi-Sol, 33 mg of Mod ucal, and 38 mg of breast-milk fortifier, and then reanalyzed. Signifi cant decreases (41% to 74%) in lysozyme activity were seen with the ad dition of all formulas; breast-milk fortifier reduced activity by 19%, while no differences were seen with Moducal, sterile water, or Poly-V i-Sol. No differences were seen in total IgA content, but some decreas es were seen in specific IgA to E. coli serotypes 04 and 06. E. coli g rowth was determined after 3 1/2 hours of incubation at 37 degrees C a fter mixing. All cow-milk formulas enhanced E. coli growth; soy formul as and other additives preserved inhibition of bacterial growth. Nutri tional additives can impair anti-infective properties of human milk, a nd such interplay should be considered in the decision on the feeding regimen of premature infants.