The research, in which the UPV/EHU–University of the Basque Country participated, associates a longer duration of breastfeeding with better cognitive development.
Various studies have associated the duration of breastfeeding with greater intellectual performance in children. Yet few studies have explored the potential protective effects of breastfeeding against behavioural problems such as symptoms of attention deficit disorder with hyperactivity (ADHD), and even less, against autistic spectrum disorders (ASD). A study, in which UPV/EHU researchers have participated, suggests that breastfeeding is positively associated with cognitive function.

The UPV/EHU lecturers Enrique Arranz and Manuel Sánchez de Miguel, and the Biodonostia researcher and UPV/EHU research collaborator seconded to the Faculty of Psychology Jesús Ibarluzea, participated in the study in which the association between the duration of breastfeeding and cognitive development, ADHD symptoms and autistic traits was examined using data from the INMA project. This project is a nationwide study, coordinated with other international studies and which analyses the effect of environmental contaminants on various aspects of child development. It is a longitudinal study which has been carried out from birth, starting in 2003 and going right up to adolescence with groups of children at different locations across Spain.

Specifically, data from a total of 1,346 children from the cohorts of Asturias, Gipuzkoa, Sabadell and Valencia were used for the research conducted now. The researchers explored whether the breastfeeding received up to four months, irrespective of whether it was of the predominant type (they received a supplement such as juices and water) or exclusive type (only breastfeeding without any additional supplementing), was linked to cognitive development, traits of the autistic spectrum or symptoms of ADHD, obtained in 2008, when the average age of the children was 4.9, the age at which the children were subjected to various tests.

In one of the conclusions the study associates, irrespective of socioeconomic factors, a longer duration of breastfeeding with greater cognitive development and a lower presence of traits of disorders in the autistic spectrum. In other words, breastfeeding has been regarded until now as having a positive effect on the child's cognitive development due to mother–baby interaction, which institutionalised children, for example, lack. Nevertheless, previous studies, thanks to the data analysis techniques existing today, had already made it possible to identify the variables separately, and to determine that the fatty acids of the type provided by breastfeeding activate the sensitivity of the neurological system to social stimuli. "What is new about this study points to the protective role against autistic traits, although it is not possible to establish the causal relationship because other factors intervene and further studies are needed," explained Jesús Ibarluzea.

To conclude, this study provides additional evidence of a positive association between breastfeeding and cognitive function aside from socio–environmental factors. It also points to a protective role against autistic traits. The results support the recommendations to extend the duration of breastfeeding in order to promote child development.

"The decision of the woman and her partner with respect to breastfeeding has to be, in any case, an informed, but free one. Breastfeeding is beneficial but it is not possible to deduce that it is essential and that not doing so is a sacrilege," said Prof Enrique Arranz.