The beneficial effects of breastfeeding are many. Children who are breastfed are at less risk of developing ear infections, colds, asthma, obesity, diabetes, and even leukemia.1 Breastfeeding has also been linked to improved brain development and lower risk for attention-deficit hyperactivity disorder (ADHD) and other behavioral problems. Because ADHD and other behavioral problems are also linked to the child’s IQ—which is, itself, also affected by breastfeeding—a group of researchers sought to determine whether or not the link between breastfeeding and behavioral development is simply the effect of the child’s IQ.

In a study published in Nutrition Journal, researchers studied almost 900 Korean children aged eight to 11 years.2 As expected, they found an association between breastfeeding and the risk of developing ADHD. When they adjusted the results to account for differences in both the child’s and mother’s IQ, they still found an association, although it was a weakened link. Also as expected, the researchers found a link between a lack of breastfeeding and lower IQ. When they adjusted the results to account for mother’s IQ and a diagnosis of ADHD, they still found an association, although also somewhat weakened.

What all this means is that breastfeeding is linked to a decreased risk of developing ADHD and also to increased IQ level. It also means that higher IQ may have a mild protective effect on the development of ADHD, and having ADHD may contribute to a somewhat lowered IQ whether or not the child was breastfed. This study is a good example of how interconnected are the various factors that contribute to our well-being. Our environment—lifestyle, diet, and habits—affects how our genes—our potential—will be played out, and almost none of it is black and white or written in stone.

ADHD affects eight to 12 percent of school-aged children.3 While ADHD tends to run in families, associated factors like lack of breastfeeding, exposure to tobacco smoke, and alcohol exposure during pregnancy also play a role. Learning how to minimize ADHD risk by optimizing these lifestyle factors can go a long way toward curbing the current trend of increased ADHD incidence.


  1. Ip S, Chung M, Raman G, et al., “Breastfeeding and maternal and infant health outcomes in developed countries.” Evid Rep Technol Assess (Full Rep). 2007 Apr;(153):1-186.
  2. Park S, Kin BN, Kim JW, et al., “Protective effect of breastfeeding with regard to children’s behavioral and cognitive problems.” Nutr J. 2014 Nov 29;13(1):111.
  3. Biederman J and Fafaone SV, et al., “Attention-deficit hyperactivity disorder.” Lancet. 2005 Jul 16-22;366(9481):237-48.