In many developed countries, the intake of added sugar by children and adolescents exceeds the recommended levels. Excessive sugar intake is thought to have adverse health consequences such as obesity. The role of sugar in the biological pathogenesis of dental caries is well understood but little research is available on whether sugar intake is associated with oral bacterial profiles. The oral microbiota, i.e. bacteria and other microbes living on the mouths surfaces and, in the saliva, are involved in maintaining both oral and systemic health. Sugar consumption might affect the oral microbiota.
The aim of a recent doctoral dissertation by Sohvi Lommi, conducted at the University of Helsinki and the Folkhälsan Research Center, was to investigate the links between sugary products and excess weight, caries and salivary microbiota in Finnish children aged 9-12 years at baseline. The study was based on data collected in the Finnish Health in Teens (Fin-HIT) -study cohort. Here, the children’s consumption frequency of sugary products, so-called sweet treats, during the preceding month was examined. These sweet treats included chocolate, sweets, biscuits, sweet pastries, ice cream and sugary juices and soft drinks. The association of the combined consumption frequency of these sweet treats and the risk of excess weight, as well as the association of changes in consumption frequency with the risk of developing excess weight were investigated. In addition, the association of the consumption frequency of sweet treats with the risk of caries and the diversity, composition and functional potential of the salivary microbiota were studied.
The research is based on the large Fin-HIT cohort including over 11 000 children across Finland.
– The research is based on the large Fin-HIT cohort including over 11 000 children across Finland. We collected information on several aspects of their health behaviour and weight in two time points which allowed us to observe longitudinal associations during early adolescence. Sweet treat consumption was measured using an index that combined several different types of sugary foods and drinks. This provides a more holistic view on sugar consumption than through examination of nutrients or single food items alone. We lacked, however, information on portion sizes and relied only on consumption frequencies, thus, the dietary data was relatively crude by nature, Lommi explains.
Sohvi Lommi, researcher at the FHRC, just defended her doctoral dissertation.
Using a cross-sectional design, the results showed that the lowest intake frequency of sweet treats was associated with an increased risk of excess weight, while the highest frequency was associated with a reduced risk. Over two years of follow-up, it was found that increased frequency of sweet treat consumption was not associated with an increased risk of excess weight, on the contrary, and somewhat surprisingly, decreased frequency of consumption was associated with an increased risk of excess weight. Furthermore, the highest frequency of sweet treats was associated with an increased risk of caries and the lowest frequency with a reduced risk of caries in a cross-sectional design. No differences in salivary bacterial diversity were observed between the low and high frequency groups. However, differences were observed in the composition and functional potential of the microbiota. For example, the metabolic pathway related to nitrate metabolism was more active in children with a highest intake frequency of sweet treats compared to the low intake frequency group.
The result might seem surprising at first, but similar findings have actually been observed in several previous studies. The inverse association could be explained for example by reverse causation.
– The result might seem surprising at first, but similar findings have actually been observed in several previous studies. The inverse association could be explained for example by reverse causation. Parents of children with excess weight may restrict child’s consumption of high-sugar foods and drinks, or children themselves may engage in dieting behaviours and restrict their food consumption. Then again, sweet treats may have a satiating effect. Depending on the type of the treat, it may contain also fat, protein and fibre which can increase satiety. Further research using more comprehensive dietary data is warranted, says Lommi.
The results suggest that tackling obesity in school-age children should not focus solely on the consumption of sugary products. The whole diet and other lifestyle factors should be considered. On the other hand, limiting the frequency of consumption of sugary products seems to be beneficial for dental health. The results on salivary microbiota opens the door to more in-depth research on the effects of sugar consumption on oral microbiota and, subsequently, on health.
Lommis dissertation may be read i full here.
Simon Granroth, Science Communicator
