Researchers have discovered that the longer a mother breastfeeds, the more intelligent their child will become later in life.
A study, published in the journal JAMA Pediatrics has provided evidence that breastfeeding in infancy leads to better cognitive development later in life, but it depends upon how long the infant is breastfed.
Researchers from Boston Children's Hospital say previous work has suggested that breast milk can boost an infant's brain as it contains docosahexaenoic acid (DHA), which helps cognitive development. They add that fish intake during lactation is a good source of DHA.
The study authors say: "Nutrients in breast milk, such as n-3 fatty acid DHA, may benefit the developing brain. A major determinant of breast milk DHA content is the mother's diet, and fish is a rich source of DHA.
"In pregnancy, greater maternal fish intake (particularly fish low in mercury contamination) is associated with better childhood cognitive outcomes, but the extent to which maternal fish intake during lactation accounts for the relationship between breastfeeding and cognition has not been reported."
Mental performance tested at 3-7 years of age
The researchers analyzed 1,312 mothers and children to see the relationship between breastfeeding duration and child cognition at ages 3 and 7 years.
Authors recommend breastfeeding until at least 12 months, and certainly past 6 months
Children were measured on whether they were breastfed milk only, received mixed feeds, weaned or were never breastfed. For 1,224 of the participants at age 3, the mean duration of any breastfeeding, including mixed feeds, was 6.4 months. The mean duration for breastfeeding only was 2.4 months.
Fish intake by mothers during lactation was also analyzed to see how this would affect associations of infant feeding and later cognition.
A series of cognitive tests were carried out, including:
- Peabody Picture Vocabulary Test at age 3
- Wide Range Assessment of Visual Motor Abilities at age 3 and 7
- Kaufman Brief Intelligence Test and Wide Range Assessment of Memory and Learning at age 7
The results showed that longer breastfeeding duration was linked with higher test scores in the Peabody Picture Vocabulary test at age 3, and higher intelligence on the Kaufman Brief Intelligence Test at age 7.
However, results showed that longer breastfeeding duration was not linked to any improvement in the Wide Range Assessment of Memory and Learning scores.
Children whose mothers had high fish intake during lactation (greater than or equal to 2 servings per week) had stronger results in the Wide Range Assessment of Visual Motor Abilities at age 3, compared with children of women who had lower fish intake (less that 2 servings per week).
The study authors conclude:
"Our results support a causal relationship of breastfeeding in infancy with receptive language at age 3 and with verbal and nonverbal IQ at school age.
These findings support national and international recommendations to promote exclusive breastfeeding through age 6 months and continuation of breastfeeding through at least age 1 year."
Dr. Dimitri Christakis, of the Seattle Children's Hospital Research Institute, has written an editorial in JAMA Pediatrics to accompany the researchers' study, calling for women to be given better opportunities to breastfeed for longer. Dr. Christakis says:
"Workplaces need to provide opportunities and spaces for mothers to use them.
Breastfeeding in public should be destigmatized. Clever social media campaigns and high-quality public service announcements might help with that."
The problem, Dr. Dimitri Christakis adds, "is not so much that most women do not initiate breastfeeding, it is that they do not sustain it."
He continues: "In the US about 70% of women overall initiate breastfeeding, although only 50% of African American women do. However, by six months, only 35% and 20%, respectively, are still breastfeeding."
It would, however, appear that breastfeeding is on the increase in the US. In an article covered by Medical News Today on 1 August 2013, the CDC suggested that within a 10-year period between 2000 and 2010, the number of babies who were first breastfed rose from 71% in 2000 to 77% in 2010.