Breastfeeding from 1 to 8 months of age is associated with better cognitive abilities at 4 years old, study finds

A study of 4- to 5-year-old children in Spain found that participants who were breastfed as infants, for 1 to 8 months, tended to have better cognitive abilities compared to their peers who were not breastfed. These children had higher IQs, better working memory, nonverbal abilities, and cognitive proficiency. The effects persisted even after adjusting for the mother’s IQ and mother-infant attachment difficulties. The research was published in the International Journal of Early Childhood.

Human breast milk is the optimal food for infants, not only because it contains a variety of nutrients, but also because its composition changes and adapts to meet the infant’s growing needs. Typically, human infants are exclusively breastfed for the first six months of life. After this period, they are gradually introduced to solid foods. However, many infants continue breastfeeding along with solid food intake until they are one or two years old, depending on individual preferences and cultural norms.

Some mothers choose to breastfeed for longer periods, while others may stop sooner. Breastfeeding requires significant commitment from the mother, as she must be available whenever the baby is hungry, which can limit her ability to leave the baby in the care of others for extended periods. Some mothers may also face challenges such as insufficient milk production. Breastfeeding can sometimes lead to sore nipples or a painful condition known as mastitis.

For these reasons, and many others, some mothers opt to raise their babies using infant formula. However, numerous studies have linked breastfeeding to various positive outcomes later in life. Individuals who were breastfed as infants have been found to be more intelligent, exhibit better psychomotor development in infancy, and even achieve higher educational attainment, social status, and income in adulthood. However, other studies have not confirmed these associations.

Study author Susana Vargas‑Pérez sought to explore whether there is a link between breastfeeding and the cognitive abilities of children at 4 to 5 years of age. She analyzed data from the ECLIPSES and EPINED studies conducted in the region of Tarragona, Spain. Both studies followed infants from birth to 4-5 years of age, collecting data on breastfeeding practices, cognitive abilities, and other relevant factors.

Free daily newsletter

The data came from 613 children born in 2013 and 2014. Information about breastfeeding was provided by the parents when the children were 4 years old. At this time, the children also completed an assessment of cognitive abilities using the Wechsler Preschool and Primary Scale of Intelligence – fourth edition. The mothers were assessed for their own intelligence using the Matrix Reasoning subtest of the Wechsler Adult Intelligence Scale – IV, and mother-infant attachment difficulties were evaluated using the Parent Stress Index – Short Form.

The results showed that children who were breastfed for 1 to 8 months had slightly better scores on several indicators of cognitive abilities compared to those who were not breastfed. These children had higher overall IQ scores, better working memory, nonverbal cognitive abilities, and higher scores on the cognitive proficiency index.

In contrast, children breastfed for more than 8 months showed significant improvements in non-verbal reasoning and overall processing speed but did not outperform the 1 to 8-month group in all areas. This suggests that while longer breastfeeding may offer some benefits, the greatest gains in cognitive development may occur within the first 8 months.

After adjusting for factors such as maternal intelligence and mother-child attachment, the relationship between breastfeeding and improved cognitive outcomes remained strong. This finding suggests that breastfeeding itself plays a crucial role in enhancing cognitive development, beyond the influences of family environment or maternal intelligence.

“Our study emphasizes the numerous advantages of breastfeeding and underscores the importance of infants being breastfed through healthcare and health policies. Advocating breastfeeding for the first six months of life is crucial for enhancing lifelong well-being and cognitive development in children,” the study authors concluded.

The study provides insight into the connections between breastfeeding and cognitive abilities. However, it is important to note that the data on breastfeeding included both exclusive breastfeeding and mixed feeding (breastfeeding combined with formula), making it difficult to determine whether exclusive breastfeeding provides a stronger cognitive advantage than mixed feeding.

Another limitation lies in the generalizability of the findings. Although the study controlled for several variables, it was conducted in a specific region of Spain, meaning the results may not apply to all populations. Cultural, economic, and healthcare differences across regions and countries could affect both breastfeeding practices and child development outcomes.

The paper, “Effects of Breastfeeding on Cognitive Abilities at 4 Years Old: Cohort Study,” was authored by Susana Vargas‑Pérez, Carmen Hernández‑Martínez, Núria Voltas, Paula Morales‑Hidalgo, Josefa Canals, and Victoria Arija.