Nutrient intakes, vitamin–mineral supplementation, and intelligence in British schoolchildren

Michael Nelson, Donald J. Naismith, Victoria Burley, Sue Gatenby, Nicola Geddes
1990 British Journal of Nutrition  
~ Children (227), aged 7-12 years, weighed and recorded all food and drink consumed for seven consecutive days. Each child completed tests of verbal and non-verbal intelligence, and was then randomly allocated to one of two groups after matching for age, sex, IQ and height. In a double-blind trial lasting for 28 d, one group received a vitamiwmineral supplement daily and the other group a placebo. On re-testing, there were no significant differences in performance between the two groups.
more » ... more, there were no consistent correlations between test scores and micronutrient intakes based on the weighed records. Thus, we found no evidence that learning ability in a cross-section of British schoolchildren was limited by the quality of their diets. Diet: Intelligence : Vitamin-mineral supplementation : Schoolchildren Nutrient deficiencies, whether dietary or metabolic in origin, have long been known to cause learning disabilities and cognitive disorders (Passmore & Eastwood, 1986), and a number of studies have shown the benefits of dietary supplements on mental function in underfed children. It was reported, for example, that thiamin supplements improved test scores in 9-to 19-year-old children living in an orphanage in Virginia (Harrell, 1946) . Pollitt ef al. (1985) presented results on the positive effect of iron supplements on cognitive performance in Egyptian children with anaemia (mean age 9-5 years), while Walter et al. (1983) showed similar effects in infants aged 15 months in whom haemoglobin levels were normal but other biochemical indicators of Fe status were low. The benefits of a supplement (energy, protein, vitamins and minerals) on the cognitive competence of infants born into poverty in Bogota, Colombia were demonstrated by Waber et al. (1981), in a prospective study lasting 3-5 years. Likewise, Barrett & Frank (1987) showed that the provision of a broad-based supplement to Guatemalan children aged 6-8 years with mild to moderate protein+nergy malnutrition resulted in improved mental test scores. In all these studies, however, evidence of undernutrition, obtained principally from anthropometric or biochemical measurements, was unequivocal. In the last two studies mentioned, the authors concluded that the effect of deprivation was to decrease motivation and arousal rather than to limit cognitive development per se, and that the benefits of supplementation diminish with increasing age. A recent paper on the effect of vitamin and mineral supplementation in British schoolchildren purported to demonstrate that in 12to 13-year-old children with apparently normal growth and no clinical signs of nutrient deficiency, additional vitamins and minerals had a positive effect on performance in tests of non-verbal intelligence (Benton & Roberts, 1988) . This is a surprising and potentially important finding. While there is a significant proportion of British schoolchildren who fail to meet the recommended daily allowance (RDA) for one or more of the micronutrients (Department of Health and Social Security, at https://doi.
doi:10.1079/bjn19900005 pmid:2205292 fatcat:xbdphpcsz5azhousdp2bhonica