Z-score of weight for age of infants with atopic dermatitis and cow's milk allergy fed with a rice-hydrolysate formula during the first two years of life

Background: Recently, rice-based formulas have been widely used in hypoallergenic diets, but data on nutritional values are scarce. Aim: To evaluate the growth of infants fed with a rice-based hydrolysate formula, compared to those infants fed with a soy formula or an extensively hydrolysed casein formula, in the first 2 y of life. Methods: A total of 88 infants were enrolled between March 2002 and March 2004. Fifty-eight infants with atopic dermatitis (AD) and cow's milk allergy (CMA), confirmed by open challenge, were enrolled as study group: 15 were fed with a rice-based hydrolysate formula (RHF), 17 with a soy-based formula (SF) and 26 with an extensively hydrolysed casein formula (eHCF). Thirty infants with AD without cow's milk allergy were recruited as a control group (CG) and fed with a free diet. Weight was recorded on enrolment and at 3-monthly intervals in the first year of life, and at 6-monthly intervals in the second year. Infants were weighed naked, before feeding, by means of an electronic integrating scale. The z-scores of weight for age were calculated. Statistics: One-way analysis of variance and Student's t-test were used for statistical comparison. Significance was set at p<0.05. Results: No significant differences between the RHF, SF and eHCF groups were observed for the z-score of weight for age during the first 2 y of life, but a significantly lower difference was seen in the RHF group compared to the control group in the intervals 9 mo-1 y (p = 0.025) and 1-1.5 y (p = 0.020) of age. In contrast, the SF and eHCF groups were comparable to the control group, but the eHCF group was significantly lower (p = 0) in the first trimester of life. Conclusion: Even if our findings show no significant difference between RHF and control, low weight observed in infants fed with RHF raises doubts about the nutritional adequacy of rice-hydrolysate formulas.