Micronutrient undernutrition in British schoolchildren.

There are few studies in children, particularly in the UK, aimed at examining relationships between the intake of specific micronutrients and currently accepted biochemical/functional indices of status. Consequently, the normal range of values for biochemical indices of status in this age-group, and the functional significance of low biochemical status, is unknown. Hence, dietary requirements have not been adequately established. As pointed out in the Committee on Medical Aspects of Food Policy (COMA) report (Department of Health, 1991), there is insufficient information on nutrient requirements for all age-groups to establish dietary reference values (DRV) with any great confidence, but there is a particular problem in relation to children over the age of 1 year. For the vitamins A, C, BIZ, riboflavin and folate, and the trace minerals Zn, Cu, and Se, DRV for children have been interpolated between values for infants and adults, or extrapolated from adult values with a factor for body weight or growth increment included in the calculation. The COMA Panel (Department of Health, 1991) found very little evidence from which to determine thiamin requirements of children. Values for vitamin Bg (1-18 years) are set at the adult level, whilst those for Fe vary, but no rationale for the calculation of these values is presented in the text. Despite the uncertainty with which DRV for children have been set, it is ‘very improbable that an individual consuming the reference nutrient intake (RNI) will be consuming insufficient amounts of that nutrient’ (Department of Health, 1991). As the proportion of a population having intakes below the RNI increases, there is an increasing risk of deficiency in that population. In the absence of any other standard, the RNI is commonly used in many studies as a bench mark by which the adequacy of nutrient intake is judged. In the first section of the present paper, therefore, the micronutrient intakes of British schoolchildren are examined in relation to the current UK reference values. This is followed by presentation of available information on the incidence of low biochemical indices of micronutrient status in children and consideration of the value of intake data for prediction of micronutrient status in this age-group. A number of studies have been performed on the micronutrient intake and status of adolescents and younger children in other countries, but despite the paucity of UK data we have resisted the temptation to make use of these results and have largely confined the discussion to the UK situation.