About 8% of schoolchildren in Denmark have underweight, but a new study shows that there is no cause for overarching concern for these children across several dietary and health measures. However, a researcher says that attention should be focused on some aspects, including their intake of vitamin B12, zinc and their bone health.
Underweight among children in Denmark may not be on most people’s minds in 2024, but about 8% of schoolchildren have underweight.
Underweight was a major health problem among children not very many generations ago, when underweight often meant malnourished. A new study concludes that few underweight children today are malnourished. It compared schoolchildren with underweight and schoolchildren with normal weight across several parameters related to diet and health.
Overall, children with underweight are as healthy as children with normal weight, although attention should be focused on some aspects.
“Previous studies found that 8% of schoolchildren in Denmark have underweight, but there is not as much focus on them as there is on children with overweight. That is why we conducted this study, examining whether children with underweight have poorer diet and nutritional status, cardiometabolic health and bone health than children with normal weight. We also investigated their school performance,” explains a researcher behind the study, Anne Aurup, PhD Fellow, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark.
The research has been published in the European Journal of Nutrition.
Data on 815 schoolchildren
The researchers included data on 815 children 8–11 years old who had participated in the Optimal Well-being, Development and Health for Danish Children through a Healthy New Nordic Diet (OPUS School Meal Study), and in that context had been measured and weighed.
Ten percent had underweight, and the researchers compared these children with the children with normal weight on numerous parameters. Underweight was defined as a low body-mass index adjusted for age and sex.
Ate less red meat and less protein
The results show no major points of concern about the health of the children with underweight.
The children with underweight ate slightly less red meat, which happens to be in accordance with the Danish Official Dietary Guidelines. They also ate slightly less protein and had lower intake of zinc and vitamin B12, which affect growth, metabolism and cognitive development and function. Vitamin B12 derives mostly from meat, so eating less red meat should mean lower intake of vitamin B12.
Children with underweight also ate slightly more sugar.
“However, our data do not show that the diet of children with underweight was healthier or unhealthier than that of children with normal weight,” says Anne Aurup.
No cardiometabolic difference
The researchers also measured the children’s cholesterol, insulin, blood pressure and heart rate as measures of cardiometabolic health and did not find great differences between children with underweight and children with normal weight. The children with underweight tended to have a slightly higher heart rate and less insulin in their blood.
According to Anne Aurup, this is probably more closely associated with the slightly lower weight and growth of the children rather than with cardiometabolic risk. This is in accordance with the fact that slightly fewer of the children with underweight had entered puberty.
“Determining what is healthy and unhealthy is difficult, but the children with underweight seem to grow a little more slowly. Then we can discuss whether this is good or bad,” notes Anne Aurup.
Slightly lower bone density
The researchers also examined the children’s bone health and found that children with underweight had lower bone density.
This is common among adults with underweight, and the reason is often that the mineralization of the bones have lower mineral density and are therefore slightly less strong when carrying around less weight.
“This is clearly one aspect that should be in focus in relation to developing healthy and strong bones in childhood and adolescence, since people must rely on the bones for the rest of adult life. This should be investigated more closely and monitored among children with underweight,” explains Anne Aurup.
Parents with more resources
The researchers found no difference in school performance across the weight groups, although children with underweight appeared to perform slightly better in tests of attention and reading skills.
The researchers also found that more children with underweight had homes with parents with higher educational attainment than in other weight groups.
“This is the opposite for children with overweight, with more parents with lower educational attainment, and that is interesting,” says Anne Aurup.
Mental health should also be investigated
Anne Aurup concludes that the results for the children with underweight should not be of concern, but attention should be focused on their bone health and the micronutrients zinc and vitamin B12.
This contrasts with the situation in low-income countries, where underweight is often associated with malnutrition and disease.
This was probably the case in Denmark 100 years ago, but today children with underweight do not seem to differ much from their peers with normal weight.
“So apart from the few focus points of zinc, vitamin B12 and bone density,” explains Anne Aurup, who adds that the conclusion is based on several studies.
She and colleagues are currently studying data on children from the Danish National Birth Cohort, examining measures of mental health and the risk of developing eating disorders and whether children with underweight differ from children with normal weight.
“We need this aspect to get the overall health picture. Although there do not seem to be major concerns about physical health, there may be more serious differences in mental health,” concludes Anne Aurup.
