Background: Aim of this study is to evaluate the incidence of diarrhea in children fed with a nucleotide-supplemented formula (Similac FormulaPlus) in comparison with formula without nucleotide supplementation.
Methods: We investigated the effects of a nucleotide-supplemented formula on the incidence of diarrheal episodes in 3315 infants with a multicenter study conduced by 386 pediatricians since March 1998 until October 1999. The study population has been divided into 4 groups based on the type of feeding; group 1 (n = 958) = exclusively nucleotide-supplemented formula, group 2 (n = 824) = exclusively formula without nucleotide supplementation, group 3 (n = 920) = mixed breast-feeding and nucleotide-supplemented formula, group 4 (n = 613) = mixed breastfeeding and formula without nucleotide supplementation. At the beginning of the study the 4 groups did not differ for body weight, length and mass index. The infants were enrolled since the first month up to the end of the third month of life and they were followed-up to the end of the sixth month of life. During the period of observation the growth of lenght, weight and mass index was similar among the 4 groups.
Results: Monthly incidence of diarrhea was computed and the comparison between group 1 and group 2 using the summary odds-ratio of Mantel-Haenszel showed that in group 1 the incidence of diarrhea was significantly lower than un group 2 (RR = 0.567); CI 95% = 0.440-0.732); similar results were obtained comparing the incidence of diarrhea between group 3 and group 4, having the former a RR = 0.630 (CI 95% = 0.476-0.834).
Conclusions: The conclusion drawn is that the supplementation with nucleotide of the formula milk decreases the risk of diarrheal episodes during the first six month of life in healthy infants. Such a positive effect is present both in exclusively nucleotide-supplemented formula and in mixed breast-feeding and nucleotide-supplemented formula fed infants. Interpretation of these results is that nucleotides, much more present in human milk than in formula milk, improve the immune defense of the infants stimulating particularly the cell-mediated immunity.