Researchers from Australia's University of Adelaide studied the eating habits of more than 7,000 children at six months, 15 months and two years, and tested their intelligence quotient at the age of eight.

Children breastfed at six months and fed a healthy diet, such as plenty of cheese, fruits and vegetables, had an IQ up to two points higher at age eight than youngsters fed poor diets in their first two years of life, Dr. Lisa Smithers said in a release Tuesday.

Smithers said researchers also found some negative impact on IQ from ready-prepared baby foods given at six months, but some positive associations when given at 24 months.

"Diet supplies the nutrients needed for the development of brain tissues in the first two years of life," Smithers said.

The study was published online in the European Journal of Epidemiology.