IQ and Breastfeeding

CQ #37 - April 3, 2017

by Anne Eglash MD, IBCLC, FABM

Does breastfeeding increase IQ? Well up until last week, we have all been under the impression that breastfeeding does increase IQ. The World Health Organization reviewed the highest quality evidence in 2013 and determined that breastfed infants have a 2-3.5 IQ point advantage. The Lancet in 2016 published data showing an average of 3.5 IQ points higher for breastfed infants, based on 16 studies that controlled for maternal intelligence and home stimulation.

The effect of breastfeeding on intelligence makes sense. Formula feeding children lack breastmilk’s growth factors, fatty acids, and other components that are so important to brain development The healthier gut microbiome in breastfed infants has also been shown to play a role in brain development. Some studies have shown how the brains of breastfed infants appear healthier and more mature than brains of formula fed infants.

Well, the facts about breastfeeding, brain development, and IQ were upended last week when multiple media sources reported on an article published in the journal Pediatrics 2017. The authors demonstrated 5940 ‘ever’ breastfed children in Ireland had no IQ advantage in comparison to 3914 formula-fed children. They controlled for most significant confounders, including maternal education, race, ethnicity, age, depression, prematurity, tobacco use, and a few others. So why did this study not jive with what we have considered factual?

What do you think could have been factors in this study, leading to lack of evidence for the relationship between breastfeeding and IQ?

The Irish mothers’ breastmilk was missing nutrients.
The duration of breastfeeding was very low, less than 10% were breastfeeding at 6 months.
The formula-fed infants received more calories.
The breastfed infants may have been mostly ‘partially’ breastfed.

Click here to view the answer to this question.

Correct Answers: The answers are B and D Read the Abstract

Breastfeeding, Cognitive and Non-Cognitive Development in Early Childhood: A Population Study

Lisa-Christine Girard, Orla Doyle, Richard E. Tremblay

Pediatrics March 2017

BACKGROUND AND OBJECTIVES:
There is mixed evidence from correlational studies that breastfeeding impacts children’s development. Propensity score matching with large samples can be an effective tool to remove potential bias from observed confounders in correlational studies. The aim of this study was to investigate the impact of breastfeeding on children’s cognitive and noncognitive development at 3 and 5 years of age.

METHODS:
Participants included ∼8000 families from the Growing Up in Ireland longitudinal infant cohort, who were identified from the Child Benefit Register and randomly selected to participate. Parent and teacher reports and standardized assessments were used to collect information on children’s problem behaviors, expressive vocabulary, and cognitive abilities at age 3 and 5 years. Breastfeeding information was collected via maternal report. Propensity score matching was used to compare the average treatment effects on those who were breastfed.

RESULTS:
Before matching, breastfeeding was associated with better development on almost every outcome. After matching and adjustment for multiple testing, only 1 of the 13 outcomes remained statistically significant: children’s hyperactivity (difference score, –0.84; 95% confidence interval, –1.33 to –0.35) at age 3 years for children who were breastfed for at least 6 months. No statistically significant differences were observed postmatching on any outcome at age 5 years.

CONCLUSIONS:
Although 1 positive benefit of breastfeeding was found by using propensity score matching, the effect size was modest in practical terms. No support was found for statistically significant gains at age 5 years, suggesting that the earlier observed benefit from breastfeeding may not be maintained once children enter school.

IABLE Comment by Anne Eglash MD, IBCLC, FABM

We are in a time period where health news reporting needs to take into consideration its impact on public health recommendations.

Multiple media sources sensationalized this study which was done in Ireland where breastfeeding rates are among the lowest in the world. Besides the fact that the breastfeeding rates in this study were less than 10% at 6 months, the authors didn’t even report on the exact percent of partial vs full breastfeeding.

So essentially there may have been no significant difference in nutrition between ‘breastfed’ and artificially fed infants.

Breastfeeding reduces illness and death among mothers and children. We already have excellent research showing that breastfeeding is associated with a higher IQ, and that breastfed infants have measurably different brain development as compared to formula fed infants.

It is shameful that the media cannot identify poor quality research. The least they could have done is provide equal time to the rich factual information that already exists on brain development, IQ and breastfeeding.

What they have done instead is undermine public health recommendations around the world with essentially fake health news.

IQ and Breastfeeding

What do you think could have been factors in this study, leading to lack of evidence for the relationship between breastfeeding and IQ?

Correct Answers: The answers are B and D Read the Abstract

Breastfeeding, Cognitive and Non-Cognitive Development in Early Childhood: A Population Study

Pediatrics March 2017

IABLE Comment by Anne Eglash MD, IBCLC, FABM

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