- A Swedish study finds that one-year-olds who were fed formula with lower-than-normal protein and energy content, yet higher-than-normal levels of milk fat globules, perform better on a cognitive development test.
- Although some have criticized the study for not measuring maternal IQ or socioeconomic status, other research on individual components of milk fat globules have suggested a role for them in brain development.
- If follow-up work with additional control variables backs the findings of this Swedish study, one of the key challenges in infant formula design will be met.
‘Breast is best’ makes theoretical sense because breast milk is the only foodstuff to have evolved specifically to meet the nutritional needs of human infants, as Bruce German, Professor of Food Science and Technology at UC Davis, is fond of saying. There are many reasons why the act of breastfeeding itself may be beneficial. But in purely compositional terms, scientists designing infant formulas rightly seek to mimic the real thing. Recently, a team of Swedish researchers ran a study in which they assigned some infants a novel formula with less energy and protein than normal infant formula, and with a higher concentration of fat globule membranes derived from cow’s milk.
At first blush, the results1 reported in The American Journal of Clinical Nutrition are impressive: when these infants reached 12 months of age, their IQ scores were statistically indistinguishable from infants who had consumed breast milk instead, but significantly higher than infants fed normal formula. The mean cognitive scores on the Bayley Scales of Infant and Toddler Development (Third Edition) were 105.8 for infants fed the novel formula, 106.4 for breastfed infants, and 101.8 for those on normal formula. So the researchers appear to have hit upon a magic recipe that responds to a long-term challenge in the field—“to create an infant formula that will optimize the neurodevelopmental outcomes of formula-fed infants to be comparable to those reported in breastfed infants,” as an editorial2 in the same journal put it. The study is the first proper clinical trial to report such a large effect on the Bayley Scales for any kind of infant formula supplementation.
However, the same editorial pours cold water on the study’s findings. Firstly, the editorial’s authors, Frank Greer of University of Wisconsin School of Medicine and Public Health, Madison, and Ronald Kleinman of Harvard Medical School, Boston, point out that the study controlled neither for maternal IQ nor socioeconomic status, two confounding factors that, in theory, should have been accounted for by the randomized design, but nonetheless could be crucial in interpreting the results. Second, they argue that is it “biologically implausible” for milk fat globule membranes to account for such a sizable effect, given the plethora of other bioactive molecules in breast milk that are absent from formula.
But the findings need not be entirely discounted. There are reasons to believe that milk fat globule membranes in the diet are important contributors to the neurological development of infants. These membranes contain three layers of particular fats and proteins, which overall are found in much lower concentrations in normal formula than in breast milk. And some have been specifically linked to neurological development, such as sialic acid, which has been shown to be present in higher concentrations in the frontal cortices of infants who consumed breast milk compared with infants who drank normal formula.3
The study researchers, Niklas Timby and colleagues at Umeå University, Umeå, Sweden, point to the most obvious way forward when they conclude that “a long-term follow-up on cognitive function with a new assessment close to school age would be desirable to find out if the difference between the formula groups persists.” If feasible, an even longer follow-up would be desirable. One trial looking at the effects of normal formula versus breast milk on IQ involving about 13,000 Belarusians followed these children into their teens, and had teachers evaluate reading and writing skills as well as IQ testing.4 Because of its length and sample size, it provides perhaps the most persuasive evidence that breast milk contributes to neurological development in ways that normal formula does not.
A follow-up to the Swedish study should also consider socioeconomic effects and maternal IQ. If such a study does find similar results to those reported in the original trial, the upshot will be a huge step forward in infant formula design—not to mention an important benefit for infants without access to breastmilk.
1. Timby N, Domellöf E, Hernell O, Lönnerdal B, Domellöf M (2014). Neurodevelopment, nutrition, and growth until 12 months of age in infants fed a low-energy, low-protein formula supplemented with bovine milk fat globule membranes: a randomized controlled trial. Am J Clin Nutr 99: 860-868.
2. Greer, FR, Kleinman RE (2014). An infant formula with decreased weight gain and higher IQ: are we there yet? Am J Clin Nutr 99: 757–758.
3. Wang B, McVeagh P, Petocz P, Brand-Miller J (2003). Brain ganglioside and glycoprotein sialic acid in breastfed compared with formula-fed infants. Am J Clin Nutr 78: 1024-1029.
4. Petherick, A. (2010). Development: Mother’s milk: A rich opportunity. Nature 468: S5-S7.
Professional science writer & editor