The study that appears in Archives of General Psychiatry tracked nearly 14,000 children born between June 1996 and December 1997 in Belarus. Half of the infants and mothers were assigned to an experimental program designed to promote breast-feeding, while the remaining infants and mothers received regular pediatric and follow-up medical care.
Six-year-olds whose mothers were part of a program that encouraged them to breast-feed had verbal IQs that were an average of 7.5 points higher than those of children in a control group, according to the study.
The longer an infant was exclusively fed breast milk, the greater the IQ improvement, said the lead scientist in the study. "Long and exclusive breast-feeding makes kids smarter," said lead researcher Dr. Michael S. Kramer of McGill University and the Montreal Children's Hospital.
The results support smaller previous studies that found children and adults who were breast fed tended to have higher IQs than whose who were not.
Kramer, a professor of pediatrics at McGill University in Montreal, said the IQ improvements could have a significant effect on society. "If we can increase IQ by 3 to 4 points in the whole population, we can have fewer children at the low end and more Einsteins at the high end," he added.
The breast-feeding program included increased counseling and instruction when women visited doctors or clinics. Researchers added that more research was needed to determine whether the benefits were related to a component of breast milk or other factors.
The World Health Organization and the American Academy of Pediatrics recommend that infants receive only breast milk during the first six months of life. Breast milk is also more easily digestible than formula, giving fewer gastric problems.
