Infants who are given nutrient- or supplement-enriched formula milk do not later have higher academic scores as adolescents than those fed with standard formula, a study published online in the BMJ suggests.
One goal of modifying infant formula has been to make long-term cognitive outcomes similar to those for breast-fed infants, the authors noted. Rates for breastfeeding beyond 6 weeks are low in many parts of the world and more than 60% of babies worldwide under the age of 6 months are given formula to replace or supplement breast milk, the paper states.
So far, research has been inconclusive on benefits, though enhancements continue to be added and claims have been made as to their benefits on cognition in advertising. Long-term trials are difficult as researchers move on and participants are lost to follow-up.
In a new study, however, researchers led by Maximiliane L. Verfürden, MsC, with the University College of London’s Great Ormond Street Institute of Child Health, linked data from seven dormant, randomized, controlled infant formula trials to participants’ performance later as adolescents in the United Kingdom on mandatory national school math and English exams at ages 11 and 16 and found no difference in scores.
They followed 1,763 adolescents who had been participants in the formula trials, which were conducted between 1993 and 2001, and were able to link 91.2% (1,607) to academic records.
They found “no benefit of the infant formula modifications on cognitive outcomes.”
Three types of formula studied
In this study, the researchers discuss three widely available types of modified infant formulas that have been promoted as benefiting cognitive development: formula enriched with nutrients; formula supplemented with long-chain polyunsaturated fatty acids (LCPUFAs); and follow-on formula fortified with iron.
In one supplement group the academic results were worse than for those given standard formula. At age 11, children who had been given the LCPUFA-enhanced formula scored lower in both English and math.
“Given the potential associations between the source of LCPUFAs and adverse cognitive outcomes, long-term follow-up of trials testing infant formulas from other sources of LCPUFAs is recommended,” the authors wrote.
Nutrients can harm, editorialist says
Charlotte Wright, BM BCH, MSc, a pediatrician and epidemiologist with the Glasgow Royal Hospital for Children in Glasgow, who was not part of the study, coauthored an editorial that accompanied the article in the BMJ.
Dr. Wright and nutritionist Ada L. Gargia, PhD, at the University of Glasgow, wrote that nutrients in some formula enhancements can harm and that infant milk trials often have been poorly conducted.
The editorialists point to a large systematic review of formula milk trials published this year in the BMJ by Helfer et al. that found that most were funded by industry.
“Helfer and colleagues’ review found that 80% of studies were at high risk of bias, mainly because of selective reporting, with 92% of abstracts mentioning positive findings, despite only 42% of trials finding statistically significant differences in a stated primary outcome,” they wrote.
Dr. Wright, who runs a specialist feeding clinic for children, said in an interview that the study is valuable in that it has follow-up “to an age when adult cognition can be robustly assessed.”
She noted that the authors say additives that have been shown to be harmful are still routinely added.
“There is now evidence that adding LCPUFAs results in lower cognition and that giving extra iron to healthy children increases their risk of infection and may even slow their growth,” she said.
But advertisements to the contrary are quickly found in an Internet search, she said, even if no specific claims are made for them.
She gave an example of an advertisement for a commonly used enhanced formula, which reads: “Our formulation contains our highest levels of DHA (Omega 3 LCPs) and is enriched with iron to support normal cognitive development.”
The formula studies were done more than 20 years ago, but Dr. Wright said that does not downplay their relevance.
The basic formulation of the formulas hasn’t changed much, she said, and the additives are still present.
This work was supported by the Economic and Social Research Council UCL, Bloomsbury and East London Doctoral Training Partnership and a Great Ormond Street Hospital Charity Research grant. Full disclosures for all authors are available with the full text of the paper. Dr. Wright and Dr. Garcia declared no relevant financial relationships.