Hydration and health: a developing scientific field

Summary

On 26 April, Danone Nutricia Research presented a satellite symposium in conjunction with the American Society of Nutrition’s scientific sessions at the 2014 Experimental Biology (EB) congress in San Diego, California. This event was an opportunity to assess and explore the research advances, issues and new challenges in hydration science.

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Every year, the Experimental Biology congress brings together scientists and researchers in the fields of anatomy, physiology, biochemistry, pathology, nutrition and pharmacology to discuss new advances in the field of biological science. The 2014 edition, one of the largest to date, took place from 26 to 30 April in San Diego. A satellite symposium organised by Danone Nutricia Research, entitled “Hydration and Health: Assessing the gaps of the science”, brought together leading scientists from various fields. The aim was to share the latest advances on the links between hydration and health. Here are the main insights shared that day.

Hydration, chronic kidney diseases and cognitive functions

Dr Erica Perrier, from Danone Nutricia Research, gave a talk entitled “From state to process: defining and assessing hydration.” She described how the human body is remarkably able to adapt to conserve body water when faced with low water consumption, but added that, in the long term, an inadequate daily fluid intake can affect health. “Recent and mounting evidence points to a link between insufficient fluid intake volume and chronic disease. Low daily water intake, low daily urine volume, and elevated urine concentration are associated with a higher risk for various chronic diseases of the kidneys, urinary tract, and metabolism,” she said. Thus, the hydration process (that is, chronic adequate water consumption) is likely to be more important for long-term health than the acute hydration state (the total body water measured at a given point in time).  One of the key challenges in this area is therefore to define hydration biomarkers for evaluating the hydration process to assess whether water intake is adequate for health.

« recent research indicates that moderate levels of dehydration, approximately 1.5% loss of body weight, adversely alter mood, produce symptoms such as headache and can result in degradation of certain aspects of cognitive performance, especially vigilance. »

Then Dr Richard J. Johnson, Professor at the University of Colorado, addressed the role of water intake in chronic kidney diseases (CKD). He described two potential mechanisms involved in dehydration and water balance that may help understand the causes of the on-going CKD epidemic among agricultural workers in Central America. Dr Johnson argued that « To date the identification of a specific toxin, pesticide or heavy metal has been elusive, and the single most important risk factor is recurrent dehydration ». Further, he showed that there is increasing evidence linking impaired kidney function and chronic kidney disease to an imbalance between water intake and loss.

Dehydration also has an impact on cognitive functions, as Dr Harris R. Lieberman explained. He spoke about the challenges in assessing the effects of dehydration on cognitive state and functions. Several studies have shown a relationship between relatively high levels of dehydration and impaired cognitive performance but only recent research shows that cognitive function and mood may be impaired in the moderate levels of dehydration which can occur more frequently in daily life. He said that « recent research indicates that moderate levels of dehydration, approximately 1.5% loss of body weight, adversely alter mood, produce symptoms such as headache and can result in degradation of certain aspects of cognitive performance, especially vigilance. »

Hydration assessment, a major challenge for the future

Dr Isabelle Guelinckx, from Danone Nutricia Research, furthered the discussion on the importance of hydration assessment in her talk “Assessing fluid intake in daily life: levers for behaviour change.” While the relationship between low fluid intake and impaired cognitive function in the short term and risk of chronic disease in the long term is increasingly documented, the general population still lacks the means to apply these findings to daily life. She mentioned that « Few food surveys report on total water intake or fluid intake. Consequently the proportion of individuals not meeting the dietary reference intake is not assessed. An inadequate water intake is nevertheless a concern as reported by recent publications. In the United Kingdom for instance, a fluid intake survey showed that 30% of adults and 50% of children did not meet the European adequate intake for total water. » It is therefore important to define an appropriate fluid intake assessment methodology in order to accurately document individuals’ fluid intake behaviour. This is a key first step in defining sustainable behaviour changes for a healthier life.

To close a very dynamic session, Dr Lawrence E. Armstrong, Professor at the University of Connecticut and Chair of the session, outlined the main perspectives and future directions for hydration research, describing the obstacles to the study of long-term health and performance outcomes and presenting future directions for research regarding the effects of dehydration on health.

With this symposium, Danone Nutricia Research furthered its commitment to participating in the advancement of hydration science, with the constant aim of finding ways to improve health through hydration. Next steps: a symposium at the European Congress on Obesity in Sofia (Bulgaria) on 29 May and the 6th annual Hydration for Health Scientific Conference, to be held in Evian (France) on 2 July. Stay tuned!

Photo ©  Shutterstock / Sezer66