Objective: To assess growth, tolerance, and biochemical measures of protein status in term infants fed an experimental formula with reduced total protein concentration and enriched in bovine alpha-lactalbumin prepared from an alpha-lactalbumin dominant bovine whey.
Methods: Healthy, term, exclusively formula-fed infants < or =14 days postnatal age, between 10th and 90th percentiles in weight and length for age were studied in this randomized, masked, multicenter study. Infants received ad libitum feedings of either experimental or control formula for 12 weeks. Adverse events and acceptability of formulas were assessed every 2 weeks. Weight, length, and head circumference were measured at baseline and every 4 weeks. Serum creatinine, albumin, and blood urea nitrogen were assessed at baseline and study completion. Anthropometric measures were compared to Centers for Disease Control reference ranges using Z scores.
Results: One hundred ninety-three infants were enrolled. One hundred thirty-four completed the protocol. Seventy-two received experimental formula, and 62 received control formula. The mean baseline body weight was higher in infants fed experimental formula (P = 0.042), so baseline weight was used as a covariate in statistical analyses. There were no differences between groups in gains in weight, length, or head circumference during the study. Mean serum albumin and blood urea nitrogen (BUN) levels were similar at study initiation. At study completion, serum albumin levels were the same in both groups, whereas BUN was significantly higher in infants fed control formula (P = 0.0016). More infants fed control (n = 20) than experimental (n = 15) formula discontinued the study because of adverse events. There were no differences in the adverse event profiles of the groups completing the study. Most of the adverse events were mild and resolved without treatment or sequelae. Acceptability and tolerance of the experimental formula was greater than the control formula, except at 2 weeks. Unacceptable ratings ranged from 0% to 10% (mean, 4.1%) in the experimental formula group and from 1.6% to 14.1% (mean, 7.0%) in the control formula group.
Conclusions: Growth and serum albumin were comparable in infants fed experimental and control formulas for the first 12 weeks of life, suggesting adequate protein nutrition from the alpha-lactalbumin-rich formula, despite its lower total protein content. Growth and adverse events data support the safety of the experimental formula. Fewer discontinuations and unsatisfactory ratings among infants fed the experimental formula suggest that it is better tolerated than control formula.