French children start their school day with a hydration deficit

Ann Nutr Metab. 2012;60(4):257-63. doi: 10.1159/000337939. Epub 2012 Jun 1.

Abstract

Background and aims: Fluid requirements of children vary as a function of gender and age. To our knowledge, there is very little literature on the hydration status of French children. We assessed the morning hydration status in a large sample of 529 French schoolchildren aged 9-11 years.

Methods: Recruited children completed a questionnaire on fluid and food intake at breakfast and collected a urine sample the very same day after breakfast. Breakfast food and fluid nutritional composition was analyzed and urine osmolality was measured using a cryoscopic osmometer.

Results: More than a third of the children had a urine osmolality between 801 and 1,000 mosm/kg while 22.7% had a urine osmolality over 1,000 mosm/kg. This was more frequent in boys than in girls (p < 0.001). A majority of children (73.5%) drank less than 400 ml at breakfast. Total water intake at breakfast was significantly and inversely correlated with high osmolality values.

Conclusions: Almost two thirds of the children in this large cohort had evidence of a hydration deficit when they went to school in the morning, despite breakfast intake. Children's fluid intake at breakfast does not suffice to maintain an adequate hydration status for the whole morning.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Child
  • Child Nutritional Physiological Phenomena*
  • Cohort Studies
  • Drinking Water
  • Drinking*
  • Energy Intake
  • European Continental Ancestry Group
  • Female
  • France / epidemiology
  • Humans
  • Linear Models
  • Logistic Models
  • Male
  • Malnutrition / epidemiology*
  • Malnutrition / physiopathology
  • Nutrition Assessment
  • Nutritional Requirements
  • Osmolar Concentration
  • Schools
  • Urine / chemistry

Substances

  • Drinking Water