European Congress on Obesity

European Congress on Obesity


Zemdegs J. Hydration in children: From fluid intake to cognitive performance. Presented at: European and International Congress on Obesity Annual Meeting; Sept. 1-4, 2020; (virtual meeting).

Disclosures: Zemdegs reports no relevant financial disclosures.
September 03, 2020
3 min read

Increased water intake may boost cognition among children


Zemdegs J. Hydration in children: From fluid intake to cognitive performance. Presented at: European and International Congress on Obesity Annual Meeting; Sept. 1-4, 2020; (virtual meeting).

Disclosures: Zemdegs reports no relevant financial disclosures.
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Water intake among children falls far below European guideline recommendations, and data suggest drinking more water can lower sugary drink consumption and even improve cognition, according to a speaker.

Data from the international Liq.in7 database, a cross-sectional survey of 6,469 children and their caregivers based on 7-day fluid intake diaries, suggests that 60% of children do not meet recommended water intake guidelines, Juliane Zemdegs, RD, PhD, a hydration scientist with Hydration for Health, said during an online presentation at the European and International Congress on Obesity virtual meeting.

Study data shows children's consumption of water vs. sugary drinks.

According to the European Food Safety Authority, a child aged 4 to 8 years should consume five 250 mL glasses of water per day; a girl or boy aged 9 to 13 years should consume at least six or seven 250 mL glasses of water per day, respectively. Data from the most recent survey show that 24% of children aged 4 to 17 years drink less than one serving of water per day, and 55% of children drink more than one serving of sugar-sweetened beverages per day.

“Here is my first message for you: Kids do not drink enough water,” Zemdegs said. “What is remarkable is, in six of the 13 countries we analyzed, children drink on average more [sugar-sweetened beverages] than water. In countries where you have a high [sugar-sweetened beverage] intake, you also have low water intake.”

Water and cognition

Water is essential for physical and mental health, Zemdegs said; several studies show water intake is associated with cognition.

In a three-intervention crossover study published in September 2019 in The Journal of Nutrition, researchers investigated the effects of water intake on urinary markers of hydration and cognition among 75 children aged 9 to 11 years (43 boys). Participants maintained their usual water intake or consumed high (2.5 L/day) or low (0.5 L/day) amounts of water for 4 days before coming to a lab to complete cognitive testing. Primary outcomes were performance on cognitive tasks requiring inhibition, working memory and cognitive flexibility assessed using a modified flanker, go/no-go and color-shape switch tasks, respectively.

During the high water intake intervention, researchers found that children exhibited 34% lower working memory during the switch task relative to the low intervention. No significant changes in cognition were observed for the flanker and go/no-go tasks.

Zemdegs said higher urine concentration was associated with lower accuracy on the switch task, noting that children's cognitive flexibility selectively benefits from greater habitual hydration and water intake.

“Water and hydration impacts kids’ cognition,” Zemdegs said. “One important question is whether kids are well hydrated and drinking enough water at school, when they need cognition to be at the best level so they can learn and pay attention.”

Creating ‘moments of hydration’

Despite spending approximately half of waking hours at school, children do not drink water there, with only 14% of total fluid intake occurring at school, Zemdegs said. Parent surveys show children prefer other beverages, do not realize they should drink more water or water is not available.

“Education is part of behavior change,” Zemdegs said. “We must tell kids why it is important to drink water and make it fun to improve water intake.”

Zemdegs said simple steps can improve water intake among children:

  • Create “moments of hydration” — Parents and caregivers should encourage children to drink water regularly before school, during lunch and dinner, during class or while outside, Zemdegs said.
  • “Drink as I do” — Survey data show that children with parents who often consume carbonated sugar-sweetened beverages were 300% more likely to drink such beverages themselves, Zemdegs said, whereas 87% of children consumed water when parents were drinking plain water often.
  • Make water accessible — Children, particularly young children, rely on adults to offer them water and make water easily accessible, Zemdegs said.

“Water and [sugar-sweetened beverages] both have an impact on health,” Zemdegs said. “Water has a positive impact on cognition, and kids may not drink enough at school and might not be well hydrated at school. What can we do to change it? First, know the barriers and why they do not drink enough. Make hydration fun and relevant, create moments of hydration, get parents involved and increase availability.”