Do we really know vitamin and mineral requirements for infants and children?

Abstract

Infants and young children require vitamins and minerals not only to replace losses through metabolic turnover, but also to increase body reserves as they grow. For infants up to six months of age it is generally assumed that breast milk provides adequate intakes, and average breast milk composition provides the basis of reference intakes for this age group, and the basis for infant formula. It is questionable to what extent the micronutrient content of breast milk reflects the infant’s requirements as opposed to the mother’s nutritional status. For obvious ethical reasons there have been very few (if any) experiments to determine the micronutrient requirements of infants and children, although studies of intakes in areas where deficiency is common provide an estimate of minimum requirements in some cases. Different national and international authorities have approached the problem of estimating reference intakes for infants and young children in four main ways: linear interpolation between adequate intakes estimated from breast milk composition and the experimentally-determined requirements of young adults; extrapolation forwards from breast milk composition and backwards from the requirements of young adults on the basis of metabolic body weight (body weight0.75), corrected by growth factors; extrapolation backwards from the requirements of young adults on the basis of the energy density of the diet; and by factorial calculation. Despite this, there is considerable concordance between the figures published by different authorities as a result of rounding off to avoid spurious precision.