Breastfeeding and IQ -the Latest Data

A recent study (JY Bernard et al J Pediatr 2017; 183: 43-50) takes a look at the relationship between breastfeeding, specific polyunsaturated fatty acid (PUFA) levels and intelligence quotient at age 5-6 years.

The authors used the French EDEN cohort with 1080 children.

Key findings:

  • Breastfed children had higher IQs by 4.5 points on Wechsler Scales –though this dropped to 1.3 (not significant) when adjusted for confounders
  • DHA was positively associated with higher IQ.  Children exposed to colostrum high in linoleic acid (LA)/ow in docosahexaenoic acid (DHA) had lower IQs than those exposed to colostrum high in DHA/low LA

The authors speculate that one reason that supplemental DHA has not been shown to be effective could be related to a high intake of LA.

Related article: CT Collins et al. NEJM 2017; 376: 1245-55.  In this study, the authors showed that enteral supplemental of DHA (60 mg/kg) did not result in a lower risk of physiological bronchopulmonary dysplasia in a randomized trial of 1273 born before 29 weeks gestation.

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With a new ballpark in town, there are a lot of firsts: first HR, first hit, etc. And now this


More on Breastfeeding and Intelligence

A recent prospective study with 30 year followup indicates that breastfeeding is associated with improved IQ and income.

A summary of the study from NBC/Today HealthAn excerpt:

Babies who are breastfed for at least a year grow up to be significantly more intelligent as adults and they earn more money, too, a new study shows….

Many experts have questioned whether it’s breastfeeding that makes babies grow up healthier and smarter, or something else that their mothers do — maybe spending more time with them. In other studies done in the U.S. and Europe, mothers who breastfeed longer tend to be more educated and affluent — and that clearly has an effect on their kids.

This study was different.

“What is unique about this study is the fact that, in the population we studied, breastfeeding was not more common among highly educated, high-income women, but was evenly distributed by social class,” Horta said.

Coverage of story from NY Times with link to original study: an excerpt:

The study, in the April issue of Lancet Global Health, began in 1982 with 5,914 newborns. The duration of breast-feeding and the age when the babies began eating solid foods was recorded. Thirty years later, researchers were able to interview and test 3,493 of the original group….

Still, the authors acknowledge that this is an observational study, and that many other unmeasured factors could have influenced their results.

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Cognitive Outcomes after Liver Transplantation

An important measure of liver transplantation (LT) is cognitive/academic outcomes. Previous studies have indicated increased intellectual deficits but were not optimally-designed.  A recent study (J Pediatr 2014; 165: 65-72) overcomes many of the limitations of previous studies.

Study design: Prospective, multicenter longitudinal cohort of neurocognitive functioning after pediatric liver transplantation.  144 participants, ≥2 years after liver transplantation -recruited through Studies of Pediatric Liver Transplantation (SPLIT).  Tested with multiple cognitive test at two separate time points.

Key findings:

  • At the time 2, 29% had full scale IQ (FSIQ) between 71-85 (compared to 14% expected); 7% had FSIQ <71 (compared with 2% expected)
  • 42% received special education.
  • Pretransplant markers of nutritional status and operative complications predicted intellectual outcome
  • Having a primary care provider with a college education was a protective factor.

One limitation of the study was that only 55% of those approached to participate were enrolled; however, the authors noted similar demographics between those who enrolled and those who did not.

What is the long-term neurological outcome in Tyrosinemia Type 1?

The answer to the blog post title: mild impaired cognitive function, according to a recent study (J Pediatr 2014; 164; 398-401).

Using a cross-sectional study, children (n=10) with tyrosinemia type 1 were compared with their unaffected siblings.  Intelligence was measured with Wechsler Scales. These children were treated with nitisinone (NTBC).  NTBC which was introduced in 1992 has markedly improved the survival of tyrosinemia by blocking the accumulation of toxic metabolites.  Liver dysfunction is controlled in >90% and the risk of liver cancer has been reduced as well.

Key results:

  • Average IQ score in tyrosinemia patients was lower than their siblings: 71 vs. 91 (P= .008).
  • In the five patients with repeated measurements, there was a gradual decline in IQ over time (240 months), from 96 to 69.


The authors do not know but speculate that cognitive impairment may have been overlooked previously due to the short life span of untreated patients.  While the lower IQ may be due to the treatment itself, “similarly low IQs in patients who stopped taking nitisone after undergoing liver transplantation argues against the acute toxicity of nitisinone.” Thus, elevated tyrosine/low phenylalanine levels, which occurs in patients on NTBC/restricted protein diet, may be related to cognitive impairment.