If previous studies, which connected intelligence and breastfeeding, have come up with conflicting results, London researchers seem to have a better answer for this issue.

Their results appearing in the latest Proceedings of the National Academy of Sciences’ journal reveal that the presence of a FADS2 gene in newborn babies explains why breastfeeding is very important for raising children’s IQ. According to this study FADS2 gene is found in 90 percent of people.

This gene is involved in the way the body processes polyunsaturated fatty acids (PUFAS) in the diets. Pufas acids are very important to the development of child’s brain because they are in charge with the transmission of nerve messages and promote the growth of nerve fibers.

These acids present only in human breast milk seem to accumulate in the brain during the first month after the babies are born, researchers said. They are not present in the cow’s milk or the infant formula but manufacturers have begun to add them after this research.

The study made by researchers at the Institute of Psychiatry, Kings College London used data from two previous studies of breast-fed babies in Britain and New Zealand, which involved 3,200 children. The children were followed between the ages of five and thirteen years.

"We took cells from the children and then analysed DNA and then we compared how they scored on IQ tests and looked up if they were breastfed as babies. It was very straightforward," Professor Terrie Moffitt of the Institute of Psychiatry at kings College, who conducted the study, said.

Researchers said that breastfed babies scored 6.8 points extra in their IQ than children raised on milk-cow or formula. These should have a significant influence on the way women feed their newborn children and consider more on breastfeeding them.

"This shows for the majority of parents they can have a positive effect on their babies IQ by breastfeeding," Belinda Phipps of the National Childbirth Trust concluded.

Breastfeeding is known to have significant advantages for children besides contributing to their IQ level. It reduces infections, respiratory illnesses and diarrhea. Moreover, a study released by the American Heart Association this week reports that breastfeeding contributes to healthier blood cholesterol levels in adulthood.

"The argument about intelligence has been about nature versus nurture for at least a century. We're finding that nature and nurture work together," Dr. Moffitt said.

In conclusion, the intellectual development is highly influenced by both environmental and genetic factors.