Is there a relationship between IQ and having been breast-fed?

Note: This is a section of a longer article. To go to the start, click here.

Yes, but a very small one. Specifically, we found that the correlation between IQ and reporting having been breast-fed in early childhood is r = 0.12 (n = 499). After we statistically adjust IQ for the effects of gender, age and data source on IQ, this negative correlation corresponds to a difference of 4 IQ points, on average, between those that were breastfed (IQ = 101) and those that were not (IQ = 97).

What do the other studies say?

These results are generally in line with several other studies that found that breastfed children had higher IQ scores, even after controlling for various confounding factors (Mortensen et al., 2002; Kanazawa, 2015; Boutwell et al., 2018).

Takeaways

• People that report having not been breastfed in infancy seem to have slightly lower IQ that people that were breastfed

  
  

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