The immunological, physical and neurological benefits of breastfeeding in infancy are now clear, but to what extent these benefits persist into later childhood and improve cognitive performance remains unclear. Researchers have therefore studied the association between the duration of breastfeeding and cognitive performance in children aged 9 to 10 years. Their results suggest clear cognitive benefits of breastfeeding, even if it only lasts a few months.
It is now known that breastfeeding is particularly beneficial, both for the health of the mother (reduction of the risk of breast cancer) and that of the child (better protection against infections). A team of researchers from the Del Monte Institute for Neuroscience at the University of Rochester Medical Center this time looked at the effects of breastfeeding on children’s cognitive performance.
They analyzed thousands of cognitive tests, carried out by American children of nine and ten years, as part of the study on the cognitive development of the adolescent brain (ABCD Study). By comparing the results of children who were breastfed for a longer or shorter period and children who were not breastfed, they demonstrated a significant positive impact of breastfeeding on cognitive abilities. A finding that could motivate more mothers to breastfeed their children.
Better capacities, regardless of the duration of breastfeeding
The analytical sample included more than 9,000 children. The test results not only revealed a clear difference between breastfed and non-breastfed children, but they also showed that the longer a child breastfed, the higher their score. ” The strongest association [entre allaitement et capacités cognitives] involved children who have been breastfed for more than 12 months », Specifies Daniel Adan Lopez, lead author of the study. The scores for children who were breastfed for 7 to 12 months were slightly lower and those for children who were breastfed for one to six months were even lower. But the researchers point out that all scores for children who were breastfed, no matter how long, remained higher than scores for children who had not been breastfed at all.
The team was particularly interested in the impact of the duration of breastfeeding on the following major cognitive components: general capacity (measure of overall intellect), executive function and memory. Previous observational studies have reported a positive association between breastfeeding and improvements in general capacity; however, these results were relatively inconsistent. While some analyzes suggested that breastfed children were ahead in their cognitive development compared to other children or had higher IQ scores, other studies did not find a significant link between breastfeeding and numeracy performance. and in reading.
Executive function encompasses a wide range of behaviors, such as planning, organizing, impulse control and goal-seeking. Again, the few studies that have examined the relationship between executive function and breastfeeding have come to mixed conclusions. Some succeeded in making a clear connection, others did not. The development of executive function begins in early childhood and continues into adulthood; it can in particular be affected by socio-economic difficulties. Finally, memory includes systems for encoding, storing and retrieving information. In children and adolescents, the ability to remember past events improves throughout adolescence. But the few studies examining the effects of breastfeeding on memory have found no association.
Lopez and his team therefore set out to examine in turn the association between the duration of breastfeeding and the different components of cognition, assuming that longer periods of breastfeeding would be strongly associated with scores. higher for all neurocognitive components later in childhood.
No impact on executive function and memory
General ability was assessed via a list sorting working memory test, an oral reading recognition test, a picture vocabulary test, a matrix reasoning test, and a mental rotation task. The executive function included the Flanker test (response inhibition test), a dimensional change-based sorting test, and a model comparison processing speed test. Finally, the memory capacity was evaluated via the Rey Auditory Verbal Learning Test (RAVLT), and an image sequence storage test.
To carry out their analyzes, the researchers also took into account all the co-variables: ethnic origin, household income, educational level and marital status of the mother. Possible smoking during pregnancy was also considered. The goal is to reduce the existing imbalance between children to consider only whether or not they have been breastfed.
Finally, the fitted linear regression model revealed a strong association between duration of breastfeeding and general fitness. The performance gap was greatest between children who had breastfed for more than 12 months and those who had never been breastfed; the association was also strong for breastfeeding lasting 7 to 12 months. However, there was no evidence that the duration of breastfeeding had any impact on executive function and memory. Scores on these cognitive tasks were admittedly lower in breastfed infants (regardless of duration) compared to non-breastfed infants, but the differences are far too small to be significant.
In conclusion, this study identified a strong association between the duration of breastfeeding and general fitness scores. She thus supports the recommendation to breastfeed her child for at least a year or more to benefit from all the cognitive advantages. According to the report of the Directorate of Research, Studies, Evaluation and Statistics published in May 2020, in France, 13.1% of children breastfed for more than 12 months.