Both in the scientific community and in the general population, a large number of benefits are attributed to breastfeeding compared to bottle feeding. In addition to the improvement of the immune system or the rate of physical growth, demonstrated by science, it is sometimes also said that breastfeeding increases the intelligence of babies
The research currently available does not allow us to definitively state that breast milk consumption has a direct relationship with IQ. However, and although there are contradictory data in this regard, the probability that there is a small but significant causal relationship between these two variables is high.
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), there appears to be a relationship between breastfeeding and better performance on tests that measure IQ.
The average of the differences, affirm the authors of this research, would be worth approximately 3.44 IQ points This is a relatively small difference but with high statistical significance and 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 taken into account that they tried to control the mother’s IQ, a variable that could interfere, but not the family socioeconomic level, which is potentially key.
Another interesting finding from this meta-analysis is that breastfeeding is not only associated with an increase in IQ, but It could also influence overall academic performance and on income level during adulthood. These effects may be due directly to breastfeeding, but also to unidentified mediating variables.
Horta and her collaborators suggest that the link between breastfeeding and increased IQ does not have to 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 is assumed that breastfeeding increases intelligence directly, 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 little ones, such as long-chain polyunsaturated fatty acids. Its consumption could enhance the development of the brain and white matter in particular, according to Isaacs and collaborators (2011).
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, this is a small increase and It has practically disappeared by the time it reaches 5 years of age
This research team found that babies who were systematically breastfed by their mothers during the first 6 months after birth showed an improvement in cognitive functions, although it was not maintained in the medium term. Therefore, in adulthood this increase in IQ would predictably be non-existent.
According to these authors, the effects found in other studies would be due to insufficient control of variables. The educational and socioeconomic levels of the parents stand out in particular which in turn are associated with better health, including a lower likelihood of tobacco use.
Different research has found relationships between early consumption of breast milk and 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 keep in mind that many of the studies on the effects of breastfeeding on the body could be biased in a similar way to those we have mentioned when describing the relationship of this food with intelligence.
Lastly, it is worth mentioning the relevance of the attachment bond between mother and baby This can have a great influence on the child’s development, especially from a psychological point of view. Breastfeeding enhances this intimate relationship, but of course there are many other elements that can do so.
Horta, BL, Loret de Mola, C. & Victora, CG (2015). Breastfeeding and intelligence: a systematic review and meta-analysis. Acta Paediatrica, 104: 14–19.
Isaacs, EB, Fischl, BR, Quinn, BT, Chong, WK, Gadian, DG & 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.
Victora, CG, Horta, BL, Loret de Mola, C., Quevedo, L., Tavares Pinheiro, R., Gigante, DP, Gonçalves, H. & Barros, FC (2015). Association between breastfeeding and intelligence, educational attainment, and income at 30 years of age: a prospective birth cohort study from Brazil. The Lancet: Global Health, 3(4): 199-205.
