Breast milk is still cited as the best milk for infants despite a new formula that appears to deliver some promising results.

Researchers from the Center for Pediatric Research divided more than 300 infants into three groups and fed them either breast milk, standard formula or formula containing nucleotides, the building blocks of genes.The study showed that nucleotides, which occur naturally in breast milk, boosted the power of immunizations in infants against certain diseases.

The babies on the formula containing added nucleotides produced more antibodies after they were vaccinated for diphtheria and Haemophilus influenzae type b (Hib), an infection that causes meningitis, than the babies fed standard formula.

But the babies that were breast-fed did best, said Dr. Larry Pickering, lead author of the study and director of the center, a joint program of Eastern Virginia Medical School and Children's Hospital of the King's Daughters.

The nucleotide study was funded in part by NIH and the Ross Products division of Abbott Laboratories, which makes Similac infant formula. Similac was used in the study.