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Waterlogged?

BMJ 2011; 343 doi: https://doi.org/10.1136/bmj.d4280 (Published 12 July 2011) Cite this as: BMJ 2011;343:d4280

Rapid Response:

Response to BMJ article by Dr Margaret McCartney (McCartney M Waterlogged ? BMJ 2011;343:d4280 doi: 10.1136/bmj.d4280

The 'Water is Cool in School' campaign
(http://www.wateriscoolinschool.org.uk) was initiated by national charity
ERIC ( Education and Resources for improving Childhood continence) and
the Royal College of Paediatrics and Child Health in 2000 to champion the
right of children to free access to adequate drinking water in school.

Children are more susceptible than adults to dehydration because of
their higher total body water content and surface area, as well as
increased activity levels. Also, they do not have the same control over
their school or home environment as adults in choosing when to drink.
There is evidence that children in the UK do not drink enough water during
the school day, with potential effects on cognition, bladder and bowel
function, obesity and dental caries.

A study in Southampton showed that 81% of children in prohibited
water-access schools and 80% of children in limited water-access schools
consumed below the minimum recommended amount of total fluid, versus 46.5%
in the free water-access schools. In total, 34.6% of children did not use
the toilets at all during the school day. There was no difference between
water access and toilet visits. 1

The association of inadequate fluid intake and bladder and bowel
problems in children is well established. It is a vital cornerstone of
treatment that these children are able to regularly drink and toilet (NICE
clinical guidelines 99 and 111).

When discussing claims of improved cognition in children with
drinking (Nursing Times 2003) by the coordinator of the "Water is Cool in
School campaign", 2 Dr McCartney highlights the referenced article by
Rogers and colleagues. 3 They found a detrimental effect of water intake
in adults who were not thirsty, as opposed to those who were thirsty, and
dismissed findings from the BBC and Leeds metropolitan University School
of Health Sciences as they had not been published in a peer reviewed
journal. An up-to-date literature search reveals two observational studies
from Israel 4 and Italy 5 demonstrating better cognitive performance in
children who were better hydrated and three interventional studies from
the UK demonstrating positive effects of drinking on cognition in six- to
nine-year olds. 6,7,8

For physiological, climatic and cultural reasons the definition of
"normal" or "adequate" drinking has not yet been defined and all we can go
by is population norms. There are two large studies from the United States
9 and Germany 10 suggesting that eight age-appropriate cups of fluid/day
is a conservative estimate. As water is a healthy drink it is not
unreasonable to recommend this.

Whilst there is no evidence-based study demonstrating the positive
effects of the "Water is Cool in School campaign", it is certainly the
impression of experts in the field as well as common sense, that this
campaign has been beneficial for the health and well-being of children. It
is a mistake to confuse promotion of excessive drinking in children with
adequate access and adequate drinking. It would be a real pity to see a
backlash against this and a return to previous poor patterns.

Dr. Anne Wright

Consultant Paediatrician, Evelina Children's Hospital, St Thomas' London

Chairman of ERIC Clinical Advisory Committee

nne.Wright@gstt.nhs.uk

1. Kaushik A et al A study of the association between children's
access to drinking water in primary schools and their fluid intake: can
water be 'cool' in school? Child: care, health and development 33 ( 4):
409-415, 2007

2. Brander N Drinking water in schools 99 (01):50, 2003

3. Rogers P et al A drink of water can improve or impair mental
performance depending on small differences in thirst Appetite 36, 57-58,
2001

4. Bar-David, Y., Urkin, J., & Kozminsky, E. (2005). The effect of
voluntary dehydration on cognitive functions of elementary school
children. Acta Paediatrica, 94, 1667-1673

5. Fadda, R., Rappinett, G., Grathwohl, D., Parisi, M., Fanari, R., &
Schmitt, J. A. J. (2008). The benefits of drinking supplementary water at
school on cognitive performance in children. 41st Annual Meeting of the
International Society for Developmental Psychobiology

6. Caroline J. Edmonds *, Ben Jeffes Does having a drink help you think?
6-7-Year-old children show improvements in cognitive performance from
baseline to test after having a drink of water Appetite 53 (2009) 469-472

7. Caroline J. Edmonds *, Denise Burford Should children drink more
water?
The effects of drinking water on cognition in children Appetite 52 (2009)
776-779

8. David Benton *, Naomi Burgess The effect of the consumption of
water on the memory and attention of children Appetite 53 (2009) 143-
146

9. Food and Nutrition Board, Institute of Medicine. Dietary
Reference Intakes for Water, Potassium, Sodium,Chloride, and Sulfate.
Washington, DC: National Academies Press; 2004. Available
at:http://www.nap.edu/books/0309091691/html.

10. Sichert-Hellert W, Kersting M, Manz F. Fifteen year
trends in water intake in German children and adolescents: Results of the
DONALD study. Acta Paediatr.2001;90:732-737

Competing interests: Chairperson of ERIC clinical advisory committee (not reimbursed/voluntary charity work)

20 July 2011
Anne J. Wright
Consultant Paediatrician
Evelina Children's Hospital, ERIC clinical advisory committee