The study raises the question of whether better education is needed about the importance of introducing at least four food groups a day after six months until the age of 2.
"Much of the previous work in the area of dietary diversity has focused on developing nations, where access to healthy and sufficient complementary foods may be limited," says Jessica G. Woo, PhD, a researcher at Cincinnati Children's and lead author of the study.
"Our research raises some concern about infants in developed nations, particularly the United States, who may not be achieving sufficient dietary diversity by one year of age. It is important to note, however, that our analysis did not determine the impact of dietary diversity on growth or nutritional status of these infants."
Dr. Woo will present her study at 1 p.m. Pacific time Saturday, May 3, at the annual meeting of the Pediatric Academic Societies in Vancouver, Canada.
The researchers studied 365 breastfed infants in Cincinnati, Shanghai and Mexico City. Dietary diversity increased between 6 and 12 months, but less than 28 percent of highly breastfed Cincinnati infants received diverse diets between 6 and 12 months - considerably fewer infants than in Shanghai and Mexico City.
Previous studies have expressed concern that if the diet isn't diverse there might be implications for poor growth in environments where food is scarce. "In Cincinnati, scarcity isn't really the issue," says Dr. Woo. "I would have worried more about scarcity in Mexico City, where the study participants are lower income, but those children seem to be achieving a reasonably diverse diet even when breastfed heavily."