water glass

If you have been following this blog or if you are in any way concerned with the increasing rates of non-communicable chronic diseases associated with Western lifestyle, you are well aware of the detrimental cardiometabolic health consequences of drinking too many sugar-sweetened beverages (SSBs) such as soft drinks, fruits juices and sports and energy drinks, especially in children and adolescents. One simple and inexpensive way for them to decrease SSB consumption is to set up strategies aiming at increasing water consumption, hoping that SSB consumption will decrease concomitantly. But, on top of hoping that increasing water intake would decrease SSBs intake and ultimately improve daily energy balance, is there any evidence suggesting that children and adolescents should increase their water consumption simply because they don’t get enough of it in the first place?

A new study conducted by researchers at the Harvard T.H. Chan School of Public Health in Boston suggests that the majority of children and adolescents in the United States (54.5% of them to be more precise) are systematically inadequately hydrated. These conclusions published in the American Journal of Public Health are based on data from the nationwide National Health and Nutrition Examination Survey from 2009 to 2012 that was conducted in 4,134 children and adolescents aged 6 to 19 years (http://ajph.aphapublications.org/doi/abs/10.2105/AJPH.2015.302572?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub%3Dpubmed). Hydration status was based on the measurement of mean urine osmolality (which provides an estimation of the number of solute particles measurements). It was also found that inadequate hydration rates were 1.76 times higher in boys compared to girls and 1.42 times higher among non-Hispanic Blacks than non-Hispanic Whites. Family income did not however predict hydration levels. Interestingly, among all beverages that may or may not predict hydration levels, only water was identified as an independent predictor. SSBs, milk, 100% juice, diet beverages, unsweetened tea or coffee or even moisture from food did not predict hydration status in these children and adolescents. Investigating water consumption habits on a typical day, the authors noticed that nearly 1 out of 4 participant did not consume any water at all. It is important to note however that these results are based on only one urine sample collected at a random time during the day and that more precise results would have been obtained if the investigators had collected 24-hour hydration status. Whether a more comprehensive assessment of urine osmolality would have yielded different results is unsure.

The authors noted that studies have directly link poor hydration status with several health consequences including reduced cognitive function, headaches and increased irritability. Moreover, poor hydration is associated with impaired physical performance. Healthy hydration is a key component of healthy lifestyle habits and the results of this study underscore the importance of encouraging kids to drink water more often. Facilitating the access to clean water in schools, public spaces, sports facilities and at home should be at the center our strategy to built a healthier environment.