The Michigan study: the relationship between sugars intake and dental caries over three years

National policies to reduce consumption of sugars to about half of their current levels have been suggested to reduce caries, an approach which assumes that caries experience is directly related to amounts of sugars consumed. This paper uses data from the Michigan diet study to question whether such policies would be effective. The Michigan study (1982-1985) collected detailed dietary information and caries incidence over a three-year period on 499 children aged 10-15 years at baseline. Results showed that caries incidence was poorly related to sugars intake, whether measured as total daily amount, between-meal intake, sugars as a proportion of total energy, or frequency of consumption. Boys had an average daily consumption of 156 g of sugars from all sources, girls 127 g. Mean caries incidence was 2.9 DMFS over the three years. When children were divided into quartiles by amounts of sugars consumed, those in the highest quartile, compared to the lowest, had a relative risk of 1.22 of developing caries. This relative risk rose to 1.80 for proximal lesions. The risks were similar when consumption was restricted to between-meal sugars. If consumption of sugars were to be cut to half that of present levels in this population, fat consumption would be likely to rise from its present level fo 38 per cent of total energy to around 47 per cent. National policies to restrict consumption of sugars might therefore be not only expensive and ineffective, but could damage the public health by inadvertently leading to higher consumption of fats.