Hydration Deficit After Breakfast Intake Among British Schoolchildren

Abstract

Nutrition surveys of British schoolchildren have not assessed hydration. This cross‐sectional study aimed to measure children's morning hydration status and to relate this to breakfast water intake. We recruited a convenience sample of 452 schoolchildren aged 9 to 11 years through primary schools in South Yorkshire. Children collected a sample of urine at home within 30min of usual breakfast for measurement of urinary osmolality. Dietary intake at breakfast was estimated using a diary method where children or parents recorded all foods and drinks consumed. A mild hydration deficit was common, with 60% of children having urinary osmolality over 800 mOsmol/kg. There was a greater prevalence of elevated osmolality in boys compared to girls (68.4% versus 53.5 %). Furthermore, 18.6 % of children recorded urinary osmolality over 1000 mOsmol/kg. We could not find any association between breakfast water intake and urine osmolality either in univariate or multivariate analysis. This lack of association may arise because of children's imprecise dietary recording and misclassification of water intake.The study was sponsored by Nestlé Waters.