The researchers suggest the findings may be relevant for obesity prevention among the younger generation. Childhood obesity is rising fast in many developed nations, such as the UK where it is already three times higher than it was just over 10 years ago, according to think-tank the International Obesity Task Force.
The team from the University of Tennessee assessed the height, weight and dietary intake of 52 children (25 bodys and 27 girls) from 2 months to age eight in a prospective longitudinal study. Body fat was measured by dual energy x-ray absorptiometry.
The researchers report in the December issue of the Journal of the American Dietetic Association (vol 103, no 12) that dietary calcium and polyunsaturated fat intake were negatively related to per cent of body fat. Total dietary fat or saturated fat, female gender, sedentary activity (hours/day), father's BMI, and mothers' percent body fat were all factors involved in outcome.
A study published earlier this year on more than 300 mixed ethnicity girls, aged nine to 14, found that those who consume more calcium tend to weigh less and have lower body fat than those with low calcium consumption.
But it is thought that girls avoid dairy products as they are associated with high fat content. Milk and other dairy products were the main sources of dietary calcium in the study, with milk alone accounting for 50 percent of the total calcium intake. In the current study, average body fat percentage of girls was already much higher than boys at age eight -26.2±7.9 compared to 22.7±6.7 for boys.
Lead author Dr Jean Skinner said that children should be encouraged to regularly eat calcium-rich foods, such as lowfat milk and yoghurt, increase physical activity and also restrict intake of carbonated soft drinks and other low-nutrient beverages. The results showed that intake of carbonated beverages and other sweetened drinks were negatively related to calcium intake.
This study is an extension of earlier research published by the same group, and one of the first to directly examine the relationship between dietary calcium intake and body fatness in children. Results suggest that dietary calcium may play a role in preventing childhood obesity.
"Even a slight decrease in body fat during childhood may reduce the risk of obesity in later childhood, adolescence and adulthood," said Dr Skinner.
Some critics have suggested that the link between calcium intake and lower body fat merely reflect a tendency towards healthy eating by those consuming more calcium.