Although low water intake triggers adverse health outcomes, available literature indicates that most children do not meet the water intake guidelines and are underhydrated based on elevated hydration biomarkers. The present review examined children′s water intake habits and hydration status from 32 observational studies (n = 36813).

It searched PubMed, Web of Science, and CINAHL to identify relevant articles. The study compared total water/fluid intake from 25 countries with water intake recommendations and assessed underhydration (urine osmolality greater than 800 mmol kg−1). It estimated the risk of bias using customized categories following the review guideline for observational studies.

The study observed-

• Among 32 studies, only 11 reported both water intake and hydration status.
• 12 out of 24 studies documented mean/median water/fluid intake below the guidelines
• 4 out of 13 studies assessing hydration status indicated underhydration based on urine osmolality (greater than 800 mmol kg−1).
• Among the 19 countries reporting a comparison of water/fluid intake with guidelines, 60 ± 24% of children (range 10–98%) failed to meet them.

These findings imply that children need to consume more water to be adequately hydrated.

Suh H, Kavouras SA. Water intake and hydration state in children. Eur J Nutr. 2019;58:475–496. https://doi.org/10.1007/s00394-018-1869-9