Infants raised on fortified formula milk showed no advantage in academic performance later on as adolescents, researchers found using data from England.

No significant differences in U.K. math exam scores were found in students at age 16 who, as infants, had participated in clinical trials comparing formulas enriched with long chain polyunsaturated fatty acids (LCPUFAs), iron, or nutrients, to standard formulas, Maximiliane Verfürden, PhD, of the University College London, and colleagues reported.

In fact, a slight reduction in academic performance was observed in children at age 11 years who had been randomized to take LCPUFA-supplemented formula, the study group reported in the The BMJ.

“Why LCPUFA supplemented infant formula might adversely affect academic performance is unclear,” the researchers wrote. In human breast milk, DHA levels are highly variable, so it is hard to pinpoint an optimal amount for formula milk, the study group said.

Docosahexaenoic acid (DHA) supplementation is mandatory in all infant formulas in England. This LCPUFA is thought to support neurodevelopment and visual acuity, but studies on DHA supplementation are not consistent.

In the U.S., DHA is an optional ingredient in infant formula.

“This study adds to mounting evidence that claims made for baby formula milks are often misleading,” commented Robert Boyle, MB ChB, PhD, of the Imperial College of London, in an email to MedPage Today.

Boyle and colleagues had published a systematic review in October that found that 80% of recently published studies on infant formulas were highly biased and only 14% were conducted independent of formula companies. “One of the weaknesses [in formula studies] is a lack of robust long-term outcome data,” Boyle said. “This new study addresses that issue, by evaluating a robust, objective outcome in a high proportion of trial participants at age 16 years.”

While previous long-term studies had high rates of attrition, this one did not due to the fact that no direct follow up was needed to obtain test scores for the participants in the initial clinical trials. This study had an 86% retention rate compared to 48% in previous long-term studies, Verfürden’s group reported.

“Current infant feeding policy has been made based on sparse evidence on the long-term effects on cognition, but we are moving in the right direction,” Verfürden told MedPage Today. “To our knowledge, our study contains the best available long-term data at this time, and it makes us more confident that long-term benefits on cognition for the studied nutritional modifications are unlikely.”

Iron supplementation in formula milk also showed no beneficial cognitive effect, the study group reported. Like DHA supplementation, iron supplementation is meant to support neurodevelopment, but past studies have found no clear cognitive benefit.

“Breast milk contains little iron, and the likely evolutionary reason for this is that iron in the gut facilitates the growth of pathogenic bacteria,” Charlotte Wright, MD, and Ada Garcia, PhD, both of the University of Glasgow, Scotland, wrote in a corresponding editorial.

“Given the lack of benefit associated with supplementary iron and its possible adverse effect on growth and now cognition, it is time to consider whether current regulations governing the composition of formula milks need review worldwide,” they said.

“The current international systems for regulating the composition of formula milks and associated health and nutrition claims are not serving the best interests of children and their carers and need reform,” Boyle agreed.

The present study pooled together seven randomized clinical trials conducted from 1993 and 2001. Data from 1,607 of the original 1,763 participants were linked to the National Pupil Database. In the six trials where participants were old enough to have taken their General Certificate of Secondary Education exams, 85.9% of participants had their math results available for analysis.

Verfürden and colleagues conceded that their analyses were powered only to detect large differences in performance between groups. They also pointed out that the original clinical trials happened 20 years ago, and the compositions of baby formulas may have changed since.

“Giving babies infant formula instead of breast milk has been shown convincingly and repeatedly to place babies at risk of harm,” Wright and Garcia nevertheless wrote.

Around the world, almost 60% of babies are fed formula milk in their first 6 months. The WHO estimates 820,000 lives could be saved every year if all children under age 2 years were optimally breastfed, given breastfeeding’s multiple health benefits.