Research has shown that breastfed babies are healthier than babies given formula and have fewer allergies and infections. And, says Michael Kramer, they're also smarter. "We found that the children in the experimental group had about three to five IQ points higher than those in the control group and that their teachers rated them slightly higher in academic subjects of reading, writing, math."

The McGill University professor of pediatrics and epidemiology led a team of researchers who analyzed the effect of breastfeeding on cognitive development. They studied 14,000 children from birth to age 6-and-a-half in the eastern European country of Belarus, where breastfeeding had not been encouraged. "In Belarus and all the former Soviet countries, the maternity hospital practices were like they were in American [hospitals] 30 years ago," Kramer says. "That was a good place to actually implement the intervention because we were able to create a difference between the experimental and controlled sites."

The experimental group adopted the UNICEF/ World Health Organization's "Baby Friendly Initiative" that promotes universal breastfeeding for infants.

Kramer says, while the gain in IQ is modest, it is a gift any mother can give to her child. "It is a comparable difference to what you find between a first born child and a subsequently born child, or a child that was read to or played with a lot by his mother and parents versus a kid who is parked in front of a television."

Kramer says his team plans to continue their work with the same children. Next they will look at risk factors for cardiovascular disease and diabetes because some studies suggest that breastfeeding may lead to a reduction in those diseases later in life. The study is published in the May issue of Archives of General Psychiatry.