Does breastfeeding increase the intelligence of babies?

Both in the scientific community and in the general population, a large number of benefits are attributed to breastfeeding compared to the use of a bottle. In addition to the improvement of the immune system or the rate of physical growth, demonstrated by science, sometimes it is also said that breastfeeding increases the intelligence of babies.

The currently available research does not allow us to definitively affirm that the consumption of breast milk is directly related to the IQ. However, and although there are conflicting data in this regard, the probability that there is a small but significant causal relationship between these two variables is high.

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Relationship between breastfeeding and intelligence

According to a meta-analysis of 17 studies on this topic carried out by Horta, Loret de Mola and Victora (2015), it seems there is a relationship between breastfeeding and better performance on tests that measure the ratio intellectual.

The mean of the differences, affirm the authors of this investigation, would have a value of approximately 3.44 IQ points. This is a relatively small difference but with high statistical significance and which is maintained in later stages of development.

However, these researchers highlight the fact that the heterogeneity between studies is high, which makes it difficult to draw definitive conclusions. Even so, it should be borne in mind that they tried to control for the mother's IQ, a variable that could interfere, but not for the potentially key family socioeconomic level.

Another interesting finding from this meta-analysis is that breastfeeding is not only associated with an increase in IQ, but also it could also influence overall academic performance and in income level during adulthood. These effects may be due directly to breastfeeding, but also to unidentified mediating variables.

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What are these effects due to?

Horta and colleagues suggest that the link between breastfeeding and increased IQ need not be due to breast milk itself but could be determined by other factors, in particular the greater interaction between the child and his mother, which would lead to an increase in the stimulation that the baby receives.

In the event that the hypothesis that breastfeeding directly increases intelligence is assumed, this causal relationship could be attributed to two main facts: and strengthening the bond between baby and mother and the nutritional richness of breast milk.

This food contains very beneficial nutrients for children, such as long-chain polyunsaturated fatty acids. Its consumption could enhance the development of the brain and white matter in particular, according to Isaacs et al. (2011).

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Evidence against this hypothesis

A longitudinal study carried out with a sample of more than 8 thousand families in Ireland (Girard et al., 2017) found a statistically significant relationship between breastfeeding and IQ in the early stages of life; however, it is a small increase and has practically disappeared by the age of 5 years.

This research team found that babies who were consistently breastfed by their mothers for first 6 months after birth showed an improvement in cognitive functions, although it was not maintained in the middle term. Therefore, in adulthood this increase in IQ would be predictably non-existent.

According to these authors, the effects found in other studies are due to insufficient control of variables. Particularly noteworthy are the educational and socioeconomic levels of the parents, which in turn are associated with better health, including a lower probability of tobacco use.

Other benefits of breastfeeding

Different investigations have found relationships between early consumption of breast milk and a better functioning of the immune system. This would help prevent a wide variety of diseases, from infections to diabetes and even sudden infant death syndrome.

In fact, the World Health Organization states that the risk of death in the first month of life is six times lower in babies who are breastfed compared to those who are exclusively bottle-fed.

In any case, it is important to note that many of the studies on the effects of breastfeeding on the organism could be biased in a similar way to those that we have mentioned when describing the relationship of this food with the intelligence.

Finally it is worth mentioning the relevance of the attachment bond between mother and baby. This can have a great influence on the development of the child, especially from a psychological point of view. Breastfeeding enhances this intimate relationship, but of course there are many other elements that can do it.

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Bibliographic references:

• Girard, L. C., Doyle, O. & Tremblay, R. AND. (2017). Breastfeeding, cognitive and noncognitive development in early childhood: a population study. Pediatrics, 139(4).

• Horta, b. L., Loret de Mola, C. & Victoria, C. g. (2015). Breastfeeding and intelligence: a systematic review and meta-analysis. Acta Pediatrica, 104: 14–19.

• Isaacs, E. B., Fischl, B. R., Quinn, B. T., Chong, W. K., Gadian, D. g. & Lucas, A. (2010). Impact of breast milk on intelligence quotient, brain size, and white matter development. Pediatric Research, 67(4): 357-62.

• Lucas, A., Morley, R., Cole, T. J., Lister, G. & Leeson-Payne, C. (1992). Breast milk and subsequent intelligence quotient in children born preterm. The Lancet, 339(8788): 261-264.

• Victory, c. G., Horta, B. L., Loret de Mola, C., Quevedo, L., Tavares Pinheiro, R., Gigante, D. P., Gonçalves, H. & Barros, F. c. (2015). Association between breastfeeding and intelligence, educational attention, and income at 30 years of age: a prospective birth cohort study from Brazil. The Lancet: Global Health, 3(4): 199-205.