Lower Protein Intake Supports Normal Growth of Full-Term Infants Fed Formula: A Randomized Controlled Trial
What this study found
IF1 (1.0 g/dL protein, 26% alpha-lactalbumin) supported growth within WHO standards and yielded weight gain similar to exclusive breastfeeding (IF1 25.8 g/day vs HM 27.0 g/day; p=0.646); IF2 (1.3 g/dL) and IF3 (1.5 g/dL) produced higher weight gain than HM (32.3 g/day and 31.5 g/day; p=0.007 and p=0.001). At 4 months, adjusted WAZ for IF1 was similar to HM and significantly lower than IF2 and IF3 (p=0.031 and p=0.014); LAZ, WLZ, HCAZ showed no meaningful differences after adjustment. This indicates that a very-low-protein formula with ~26% alpha-lactalbumin can support normal growth akin to…
- Study & population
- Single-blind randomized controlled trial at six medical centers in Querétaro, Mexico; 308 healthy full-term singleton infants enrolled (birth ≥37 weeks, weight 2500–4000 g, second Apgar >8, age ≤40 days at entry); IF groups: IF1 (n=30), IF2 (n=24), IF3 (n=42); control breastfed HM group (n=212); anthropometrics and WHOMulticenterGrowthReference scores…
- Intervention
- Three infant formulas fed from 1 month to 4 months: IF1 (total protein 1.0 g/dL; enriched with bovine alpha-lactalbumin to 26% of total protein), IF2 (1.3 g/dL; enriched with bovine alpha-lactalbumin to 26%), IF3 (1.5 g/dL; alpha-lactalbumin 11%).
- Key limitation
- Short intervention window (1–4 months) limits assessment of long-term growth and metabolic outcomes; metabolic profiling not performed; high dropout rate (~53%), though statistical power remained adequate; some baseline differences in anthropometrics.
View source
Open PDFOriginal abstract
Infant formulas have been conventionally prepared with an excess of total protein in order to provide sufficient amounts of essential amino acids to the rapidly growing infant. However, this practice leads to higher than necessary protein intake during early infant development, inducing accelerated growth patterns correlated with the development of chronic diseases later in life. This study was aimed at assessing the safety of an infant formula enriched with bovine alpha-lactalbumin containing a total protein concentration very close to that of human milk, and determining its efficacy in the support of healthy infant growth from the first month to the fourth month of age. Healthy full-term infants ≤40 days of age were randomized in this controlled single blind trial to one of the following infant formulas: IF 1 (containing 1.0 g protein/dL; n = 30), IF 2 (containing 1.3 g protein/dL; n = 24), and IF 3 (containing 1.5 g protein/dL; n = 42). A control group consisting of exclusively breastfed infants (HM; n = 212) was included in the study. Anthropometric measurements and Z-scores were evaluated at baseline, at 1 month of age, and at 4 months of age. Weight gain (g/day) was similar in the IF 1 and the HM groups (p = 0.644), and it was significantly greater in the IF 2 and IF 3 groups than in the HM group. Growth patterns in both breastfed or IF-fed infants were in accordance with the World Health Organization (WHO) growth standards. At four months of age, the mean weight-for-age Z-score (WAZ) adjusted for initial value in the IF 1 group was similar to that of the HM group and significantly lower than that of the IF 2 and IF 3 groups (p = 0.031 and p = 0.014 for IF 2 and IF 3, respectively). Length-for-age (LAZ) adjusted for initial value was similar among all groups at four months of age. From 1 to 4 months of life, IF 1 containing 1.0 g protein/dL promotes growth and weight gain similar to those observed in exclusively breastfed infants. As this is a first approach to studying an IF containing total protein in a level below that recommended by international committees on nutrition, further investigations are needed to support these findings evaluating infant’s metabolic profile and growth in the long term.