A study published in the September 2013 issue of JAMA Pediatrics indicates a causal relationship of breastfeeding duration with receptive language and verbal and nonverbal intelligence later in life.
Previous research suggests that there is a link between breastfeeding and health benefits in infancy, but the long-term effects of breastfeeding on cognitive development remain poorly understood.
A 2007 systematic review and meta-analysis, carried out by WHO on the long-term consequences of breastfeeding showed that breastfeeding was associated with an increase of intelligence tests at childhood and adolescence.
In a 1992 randomized trial in the UK, the mean IQ was higher in preterm children who were randomly allocated to receive breast milk than in those who received formula. Of note, in this study, a “dose-response relation between the proportion of mother’s milk in the diet and subsequent IQ” was observed.
In the JAMA Pediatrics study Mandy Belfort and colleagues, from the of Boston Children’s Hospital investigated participants in ‘Project Viva’, a prospective, longitudinal cohort study designed to examine prenatal factors in relation to pregnancy and child health.
The authors of this study found that longer duration of breastfeeding and greater exclusivity of breastfeeding were associated with better receptive language at age 3 years and with higher verbal and nonverbal IQ at age 7 years.
Thus, this study seems to support a causal relationship of breastfeeding in infancy with receptive language at age 3 and with verbal and nonverbal IQ at school age.
As per the authors, the study also support national and international recommendations to promote exclusive breastfeeding through age 6 months and continuation of breastfeeding through at least age 1 year.
Update: A 2015 systematic review and meta-analysis confirms that breastfeeding is related to improved performance in intelligence tests. In addition, a prospective, population-based birth cohort study of neonates launched in 1982 in Pelotas, Brazil, and published in Lancet, indicates that breastfeeding is associated with improved performance in intelligence tests 30 years later.
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