Hydration in Europe

From SEFYMEN

Water is an essential macronutrient whose importance is often overlooked.

Maintaining adequate hydration is crucial for ensuring optimal physical and mental health, both in children and adults.

Many adults and children in Europe do not hydrate sufficiently to meet EFSA recommendations for adequate water intake and may be at risk of metabolic disease, such as obesity and type‑2 diabetes.

The type of liquids consumed as part of a healthy diet must be taken into account, and water should be promoted as the healthiest choice, given that it comes from nature and contains no calories.

Increasing water consumption would result in improved health, with additional associated cost‑benefit advantages.

Water – the “forgotten” nutrient

Water is a fundamental macronutrient that is often omitted from dietary recommendations and guidelines.

It is the dominant component of our bodies and changes throughout the lifespan.

At birth, about 80 % of body weight is water. This proportion gradually declines during childhood, stabilising in adulthood at around 60–65 %. From that point onward, as age progresses, total body water (TBW) slowly falls to about 55 % in the elderly.

The proportion of total body water varies according to a range of factors, including body‑fat percentage, muscle‑mass composition and sex; for example, young adult males have a higher TBW percentage than women of the same age and weight.

Recommendations for adequate water intake

The European Food Safety Authority (EFSA) was one of the first organisations to recognise water as a nutrient and to issue recommendations on adequate intake (AI) (1).

Thirst is often regarded as the best indicator of water needs and the recommendations as unnecessary. However, fluid intake may satisfy thirst without fully hydrating the body’s cells. Moreover, thirst is not a reliable indicator of under‑hydration or dehydration in children or the elderly.

Guidelines are essential to inform the public about how to maintain a healthy hydration status.

It is important to recognise that water is obtained not only from drinks but also from foods. EFSA estimated that, in Europe, foods provide roughly 20 % of the recommended water intake (TWI).

This estimate was based on data that were available at the time, however, more recent evidence suggests that this may be an underestimate (2–4).

The EFSA recommendations for adequate water intake, regarding total water intake (TWI), and the calculated fluid intake are presented in Table 1.

The intake data available to the research team were limited and derived from population surveys that used a variety of assessment tools which had not been validated for assessing water and/or fluid intake (5).

Given that several studies on European populations have now been published (4,6–8), some of which used a validated fluid‑recording diary (9–11), it is timely to review the existing intake recommendations.

Furthermore, it is important that the general dietary guidelines applicable in Europe include water and fluids.

Assessing water and/or fluid intake is a significant challenge (6) and, as a result, it can be difficult for the public to self‑assess their intake.

The easiest way to determine whether one is well hydrated is to monitor the colour of urine. Light‑coloured, more “dilute” urine indicates adequate hydration, whereas dark urine is excreted when the body is dehydrated. Valid urine‑colour charts are available for adults, children and pregnant women (12–14).

European standards for water/fluid consumption

Water and fluid intakes across Europe vary greatly (8,15) and, based on the reported intakes, range from, for example, 559 mL per day in adult Irish people to around 2 500 mL per day in Sweden (8).

A substantial number of adults in Europe do not consume enough fluids to meet the EFSA recommendations for adequate water intake.

Again, this finding shows considerable variability; for instance, 26 % of German adults consume less than the recommended amount, compared with almost 70 % in France and 65 % in Poland among the corresponding populations (11).

The reports also showed that a significant proportion of children in Europe do not meet these specific recommendations (16).

There is growing evidence linking low fluid intake with an increased risk of metabolic disease (17). The proportion of people consuming inadequate amounts of water has been reported to reach 90 % in France (10).

It is also important to consider the types of fluids consumed, especially sugary drinks (SSB). Numerous studies have shown that children and adolescents in Europe consume substantial amounts of sugar‑sweetened beverages (SSB) (18). A recent Spanish

A study reported that 40 % of children (aged 4‑9) and 50 % of adolescents (aged 10‑17) consumed at least one portion of sugar‑sweetened beverages (SSB) per day (19).

Hydration and health

The importance of water and fluid intake and of hydration, for both physical and mental health, is being increasingly recognised.

It is no longer just about satisfying thirst, but about optimising health, with a reduction in health risks associated with low fluid intake.

There is a body of research showing that low fluid intake, or its associated biomarkers, are linked to an increased risk of metabolic diseases (17,20,21), including obesity, type‑2 diabetes, cardiovascular disease and mortality.

With continually rising obesity rates and the related non‑communicable diseases in Europe, it is vital to consider the role that healthy hydration can play in curbing these conditions.

Adequate hydration is also important for cognitive function. Ensuring sufficient hydration has been shown to improve cognition in children (22,23) and adults (24) and to enhance mood (25,26).

Ensuring adequate hydration will bring many benefits to children and adults, in school and work performance respectively, as well as mental wellbeing.

Conclusion

Water is an essential macronutrient and adequate intake is important for maintaining optimal physical and mental health.

Intake merely to satisfy thirst may not result in sufficient cellular hydration; therefore it is important that people ensure they drink enough fluids to meet the recommended adequate intake levels.

Many people in Europe do not consume enough fluids to meet European recommendations and as a result may be at increased risk of metabolic diseases.

Furthermore, high levels of consumption of sugar‑sweetened beverages (SSB) can contribute to the increased prevalence of obesity, type‑2 diabetes and cardiovascular disease.

Hence, it is crucial to recognise the role of proper hydration and to implement appropriate policies and programmes.

Water is the healthiest choice, being natural and calorie‑free.

Increasing water consumption would lead to overall health improvement with accompanying cost benefits.

Table 1. EFSA recommendations for adequate daily total water intake and calculated fluid intake based on 20 % of water consumed via foods.

Age and developmental stages			Total adequate water intake (L/day)	Fluid intake (≈ 80%) (L/day)
Children	1–2 years		1.1 – 1.2	0.9 – 1.0
	2–3 years		1.3	1.0
	4–8 years		1.6	1.3
	9–13 years	Boys	2.1	1.7
		Girls	1.9	1.5
	> 14 years		As for adults	As for adults
Adults	Men		2.5	2.0
	Women		2.0	1.6
Elderly			As for adults	As for adults

References

1. EFSA. Scientific Opinion on Dietary Reference Values for water. EFSA J. 2010;8(3):2–3.
2. Guelinckx I, Tavoularis G, König J, et al. Contribution of water from food and fluids to total water intake: Analysis of a French and UK population surveys. Nutrients. 2016;8:630.
3. O’Connor L, Walton J, Flynn a. Water intakes and dietary sources of a nationally representative sample of Irish adults. J Hum Nutr Diet. 2013;27:550-556.
4. Nissensohn M, Sánchez-Villegas A, Ortega RM, et al. Beverage Consumption Habits and Association with Total Water and Energy Intakes in the Spanish Population: Findings of the ANIBES Study. Nutrients. 2016;8(4):232.
5. Gandy J. Water intake: validity of population assessment and recommendations. Eur J Nutr [Internet]. 2015;54(2):11–6.
6. Gandy J, Le Bellego L, König J, et al. Recording of fluid, beverage and water intakes at the population level in Europe. Br J Nutr [Internet]. 2016;116(04):677–82.
7. Vieux F, Maillot M, Constant F, Drewnowski A. Water and beverage consumption patterns among 4 to 13-year-old children in the United Kingdom. BMC Public Health. 2017;17(1):479.
8. Elmadfa I, Meyer AL. Patterns of drinking and eating across the European Union: implications for hydration status. Nutr Rev. 2015;73:141–7.
9. Johnson EC, Péronnet F, Jansen LT, et al. Validation testing demonstrates efficacy of a 7-day fluid record to estimate daily water intake in adult men and women when compared with total body water turnover measurement. J Nutr. 2017;147(10):2001–7.
10. Iglesia I, Guelinckx I, De Miguel-Etayo PM, et al. Total fluid intake of children and adolescents: cross-sectional surveys in 13 countries worldwide. Eur J Nutr. 2015;54:57-67.
11. Ferreira-Pêgo C, Guelinckx I, Moreno LA et al. Total fluid intake and its determinants: cross-sectional surveys among adults in 13 countries worldwide. Eur J Nutr. 2015;54(2):35–43.
12. Armstrong L, Maresh C, Castellani J, et al. Urinary indices of hydration status. Int J Sport Nutr. 1994;4(3):265–79.
13. Guelinckx I, Fremont-Marquis AS, Eon E, et al. Assessing Hydration in Children: From Science to Practice. Ann Nutr Metab. 2015;66(3):5–9.
14. McKenzie AL, Armstrong LE. Monitoring Body Water Balance in Pregnant and Nursing Women: The Validity of Urine Color. Ann Nutr Metab. 2017;70(Suppl1):18–22.
15. Vergne S. Methodological Aspects of Fluid Intake Records and Surveys. Nutr Today. 2012;47(4):S7–10.
16. Vieux F, Maillot M, Constant F, Drewnowski A. Water and beverage consumption among children aged 4-13 years in France: analyses of INCA 2 (Étude Individuelle Nationale des Consommations Alimentaires 2006-2007) data. Public Health Nutr. 2016;19(1):2305–14.
17. Perrier ET, Armstrong LE, Bottin JH, et al. Hydration for health hypothesis: a narrative review of supporting evidence. Eur J Nutr. 2020;60:1167-1180.
18. Guelinckx I, Iglesia I, Bottin JH, et al. Intake of water and beverages of children and adolescents in 13 countries. Eur J Nutr. 2015;64:69-79.
19. Iglesia-Altaba I, Miguel-Berges ML, et al. Are Spanish children drinking enough and healthily? An update of the Liq.In7 cross-sectional survey in children and adolescents. Nutr Hosp. 2021;34(1):15–8.
20. Vanhaecke T, Dolci A, Fulgoni VL, Lieberman HR. Associations between urinary hydration markers and metabolic dysfunction: a cross-sectional analysis of NHANES data, 2008–2010. Eur J Nutr]. 2021;2008–10.
21. Stookey JD, Kavouras SΑ, Suh H, Lang F. Underhydration Is Associated with Obesity, Chronic Diseases, and Death Within 3 to 6 Years in the U.S. Population Aged 51-70 Years. Nutrients. 2020;12(4):905.
22. Edmonds CJ, Burford D. Should children drink more water?. The effects of drinking water on cognition in children. Appetite. 2009;52(3):776–9.
23. Khan NA, Westfall DR, Jones AR, et al. A 4-d Water Intake Intervention Increases Hydration and Cognitive Flexibility among Preadolescent Children. J Nutr. 2019;149(12):2255–64.
24. Wittbrodt MT, Millard-Stafford M. Dehydration Impairs Cognitive Performance: A Meta-analysis. Med Sci Sports Exerc. 2018;50(11):2360–8.
25. Pross N, Demazières A, Girard N, et al. Effects of changes in water intake on mood of high and low drinkers. PLoS One. 2014;9(4).
26. Suh H, Lieberman HR, Jansen LT, Colburn AT, Adams JD, Seal AD, et al. Cellular dehydration acutely degrades mood mainly in women: a counterbalanced, crossover trial. Br J Nutr. 2020;125:1092-1100. 1–9.