Findings by the Swiss and US researchers point to a link between rapid weight gain after birth and a later risk of obesity and possible chronic disease outcomes.
Breastfeeding, compared with feeding traditional (high-protein) formulas, has been identified as a protective factor against obesity later in life.
The study states that lowering the protein content of infant formula so it is closer to that of mature breast milk may reduce the long-term risk of overweight or obesity in formula-fed infants.
The study notes that while the underlying biological mechanisms are not clear, one theory, known as the “early protein hypothesis,” attributes this possible protective relation to the protein content of feedings.
Formula-fed infants, it states, may be exposed to a high amount of protein that may increase their risk of negative health conditions later in life.
Protein for amino acids
The authors state that infant formula is generally higher in protein to ensure infants receive adequate amounts of amino acids for growth and development.
However, they continue to state that advances in protein technology have led to the development of a whey-predominant protein that is used to manufacture lower-protein infant formula (LPF) and LPF with additional active ingredients (probiotics, prebiotics, or both) (LPFA).
At 1.8 g protein/100 kcal, the protein-to-energy ratio of LPF and LPFA is closer to that of breast milk and represents the lowest regulatory permissible limit for protein in infant formula in the US and the EU.
The study assessed the effects of whey-predominant formulas with a protein content of 1.8 g/100 kcal on infant growth by comparing against WHO growth standards and breastfed infants.
A multicenter pooled analysis was conducted with the use of 1,882 participants from 11 randomized controlled trials of healthy term infants.
Models were generated to estimate weight-for-age z score (WAZ), as well as length-for-age, BMI-for-age, and head circumference-for-age z scores at four months of age.
This was carried out on three groups of infants: those fed LPF; ones given LPFA; and breastfed infants.
Estimates of WAZ were within ±0.5 SD of WHO growth standards for the LPF [0.07 (−0.16, 0.29)] and LPFA [0.22 (0.01, 0.43)] groups.
WAZ was higher in the LPF and LPFA groups than in the breastfed infants, which the authors say is likely because breastfed infants had a relatively low WAZ compared with WHO growth standards.
The authors concluded that whey-predominant infant formula with a lower protein content that more closely resembles that of breast milk supports healthy growth comparable to the WHO growth standards, and is closer to breastfed infants.
Source: The American Journal of Clinical Nutrition
Growth of infants consuming whey-predominant term infant formulas with a protein content of 1.8 g/100 kcal: a multicenter pooled analysis of individual participant data
Authors: Dominik D Alexander, Jian Yan, Lauren C Bylsma, Robert S Northington, Dominik Grathwohl, Philippe Steenhout, Peter Erdmann, Evelyn Spivey-Krobath, and Ferdinand Haschke
First published September 7, 2016