Corrected: Clarification: An item in this story provided an inexact definition of children who are overweight. Researchers define overweight children as those who are above the 95th percentile in weight for children of the same height.
Three studies published in the latest issue of the journal Pediatrics offer insight into the effects of diet on children.
In one of the first studies to link hunger to a child’s behavioral problems in school, researchers found that habitually hungry children from low-income families are seven times more likely as those who aren’t hungry to misbehave in class, fight, be enrolled in special education, or have psychological problems.
According to the study published in the January issue, chronic food insufficiencies may have just as much influence on a poor child’s behavior as other factors as such living with a single parent or being exposed to violence.
For the study, researchers, led by Dr. Ronald E. Kleinman of the Harvard University Medical School, interviewed 328 parents and children living in the Pittsburgh area in 1993 and asked them about the availability of food in their homes and their children’s behavior in school.
Twenty-one percent of the parents of hungry children reported some “psychosocial dysfunction,” such as fighting, not listening to rules, or stealing. In contrast, only 3 percent of children who were not routinely hungry displayed similar behaviors.
Less than 1 percent of children in the United States suffer from malnutrition, meaning that they weigh less than 95 percent of children their height, according to the study. But hunger--defined as intermittent episodes of prolonged food insufficiency--is becoming more common, according to the authors.
“The data from this study reveal that hunger seems to have a unique impact on the psychosocial functioning of poor children,” the authors write.
Children who were breast-fed as babies tend to perform better in school and score higher on reading and math tests than children who were bottle-fed as infants, another of the studies says.
For the longitudinal study, a team of New Zealand researchers followed more than 1,000 children from birth to age 18. They gathered information on breast-feeding practices from birth to age 1 and tracked the children’s school performance on standardized reading and math tests and on school exit exams from ages 8 to 18. The researchers examined the children’s progress from 1977 to 1995.
Researchers L. John Horwood and David M. Fergusson from Christchurch School of Medicine found that children who were breast-fed for a minimum of three months to five months scored higher on standardized tests from ages 8 to 13 than children who were bottle-fed. Performance improved the longer children were breast-fed.
The authors say that the fatty acids in mothers’ milk, which are not present in store-bought formula, explain the differences in achievement.
Some critics, however, have said that because the breast-fed children in the study tended to have wealthier and better-educated mothers with higher IQs, factors other than breast-feeding might have contributed to the differences in performance.
But the authors note that even after taking into account a number of variables, such as education level, wealth, and age of the mother, breast-fed children still performed better academically.
A new federal study, meanwhile, shows that one in 10 preschool children from low-income households is overweight, a condition that has risen sharply in the past decade.
Researchers at the Centers for Disease Control and Prevention, who reviewed more than 15 million medical records of poor children younger than 5, found that the percentage of such children who were overweight rose 20 percent in the past decade, from 8.5 percent in 1983 to 10.2 percent in 1995.
The rise was greatest among 4-year-olds, climbing 30 percent during the same period. Increases in poor children who are overweight--defined as being in the 95th percentile in weight for their age group--showed up even among 2-year-olds.
Earlier research has shown that obesity among adolescents and adults has been increasing, but this is the first to note such a change in very young children, the study says. The CDC study shows parallel gains for boys and girls and for black, Hispanic, and white children.
It is unclear whether the sharp rise among the youngest children stems from increased television viewing, consumption of fattier foods, or decreasing physical activity, said Kelley S. Scanlon, an epidemiologist at the CDC and an author of the study.
But she suggested that parents of overweight children should serve more nutritious, low-fat foods and give their children more control over how much they consume.
“Young children should not be put on diets,” Ms. Scanlon said. “But they also shouldn’t be forced to clean their plates.”
