Children who were breastfed exclusively for at least three months had better intelligence scores later in life than those who received formula, according to the largest study on the subject.
Breastfed children received better results in verbal, non- verbal and overall intelligence tests and significantly higher academic ratings in reading and writing at the age of six than those who received formula, according to a study in the Archives of General Psychiatry.
The World Health Organization and the United Nations Children’s Fund promote breast-feeding, which they say is cheaper, more convenient and may be healthier and better for cognitive development. The study’s findings confirm results from other research that has suggested a positive effect of breast-feeding on intelligence.
“These results, based on the largest randomized trial ever conduced in the area of human lactation, provide strong evidence that prolonged and exclusive breast-feeding improves children’s cognitive development,” said study author Michael Kramer from the Montreal Children’s Hospital.
The researchers looked at 17,046 healthy infants who were breastfed at maternity hospitals in Belarus and followed up 13,889 of these at the age of 6.5 years. They studied IQ scores on the Wechsler Abbreviated Scales of Intelligence and teacher evaluations of performance in reading, writing and mathematics.
Children who were breastfed scored 7.5 points higher on verbal intelligence scores, 2.9 points higher on non-verbal intelligence scores and 5.9 points higher on tests measuring overall intelligence.
The study is limited by the fact that the researchers don’t know whether the positive effect on intelligence scores comes from breast-feeding or from characteristics of the mothers who are more likely to nurse. The researchers didn’t include the cognitive abilities of the parents.
Scientists also can’t tell whether the benefits of breast-feeding are because of some constituent of breast milk such as long-chain polyunsaturated fatty acids or if they are related to the physical and social interactions inherent in breast-feeding.
The number of mothers who start breast-feeding has increased substantially over the last 30 years, Kramer said. Much less progress has been made in increasing the exclusivity and duration of the practice, Kramer said.
“Because protection against infections in developed country settings doesn’t have the life-and-death implications for infants and child health that it does in less-developed settings, cognitive benefits may be among the most important advantages for breastfed infants in industrialized societies,” Kramer said.