Total water intake guidelines are sufficient for optimal hydration in United States adults.

PURPOSE: Recent studies suggest that 24-h urine osmolality (UOsm) for optimal water intake should be maintained < 500 mmol·kg-1. The purpose of this study was to determine the total water intake (TWI) requirement for healthy adults to maintain optimal hydration as indicated by 24-h urine osmolality < 500 mmol·kg-1. METHODS: Twenty-four-hour UOsm was assessed in 49 men and 50 women residing in the United States (age: 41 ± 14 y, body mass index: 26.3 ± 5.2 kg·m-2). TWI was assessed from 7-day water turnover, using a dilution of deuterium oxide, corrected for metabolic water production. The diagnostic accuracy of TWI to identify UOsm < 500 mmol·kg-1 was evaluated using receiver operating characteristic (ROC) analysis in men and women separately. RESULTS: Twenty-four-hour UOsm was 482 ± 229 and 346 ± 182 mmol·kg-1 and TWI was 3.57 ± 1.10 L·d-1 and 3.20 ± 1.27 L·d-1 in men and women, respectively. ROC analysis for TWI detecting 24-h UOsm < 500 mmol·kg-1 in men yielded an area under the curve (AUC) of 77.4% with sensitivity, specificity, and threshold values of 83.3%, 64.5%, and 3.39 L·d-1, respectively. The AUC was 82.4% in women with sensitivity, specificity, and threshold values of 85.7%, 72.1%, and 2.61 L·d-1. CONCLUSION: Considering threshold values in men and women of 3.4 L·d-1 and 2.6 L·d-1, respectively, maintaining TWI in line with National Academy of Medicine guidelines of 3.7 L·d-1 in men and 2.7 L·d-1 in women should be sufficient for most individuals in the United States to maintain 24-h UOsm < 500 mmol·kg-1.

Validity and Reliability of a Water Frequency Questionnaire to Estimate Daily Total Water Intake in Adults.

The purpose of this investigation was to assess the validity and reliability of a seven-day water frequency questionnaire (TWI-FQ) to estimate daily total water intake (TWI) in comparison to a water turnover objective reference value via deuterium oxide (D2O). Data collection occurred over 3 weeks, with a wash-out period during week two. Healthy adults (n = 98; 52% female; 41 ± 14 y; BMI, 26.4 ± 5.5 kg·m-2) retrospectively self-reported consumption frequencies of 17 liquids and 35 foods with specified volumes/amounts for weeks one and three via TWI-FQ. Standard water content values were utilized to determine the volume of water consumed from each liquid and food for calculation of mean daily TWI for each week. Diet records were completed daily during week two to estimate metabolic water production. To assess validity of the TWI-FQ, participants consumed D2O at the start of each week and provided urine samples immediately before ingestion, the following day, and at the end of the week to calculate water turnover. Metabolic water was subtracted from water turnover to estimate TWI. TWI-FQ validity was assessed via Bland-Altman plot for multiple observations. Reliability was assessed via intraclass correlation and Pearson's correlation between weeks. TWI-FQ significantly underestimated D2O TWI by -350 ± 1,431 mL·d-1 (95% confidence interval (CI): -551, -149 mL·d-1). TWI-FQ TWI was significantly correlated (r = 0.707, P <0.01) and not different (198 ± 1,180 mL·d-1, 95% CI: -38, 435 mL·d-1) between weeks. TWI-FQ intraclass correlation = 0.706 was significant [95% CI: 0.591, 0.793; F (97, 98) = 5.799], indicating moderate test-retest reliability. While this tool would not be suitable for individual TWI assessment, the magnitude of bias may be acceptable for assessment at the sample-level.

Combining urine color and void number to assess hydration in adults and children.

BACKGROUND/OBJECTIVES: To test the diagnostic ability of two combined practical markers for elevated urine osmolality (underhydration) in free-living adults and children. SUBJECTS/METHODS: One hundred and one healthy adults (females n = 52, 40 ± 14 y, 1.70 ± 0.95 m, 76.7 ± 17.4 kg, 26.5 ± 5.5 kg/m2) and 210 children (females = 105, 1.49 ± 0.13 m, 43.4 ± 12.6 kg, 19.2 ± 3.2 kg m-2) collected urine for 24-h. Urine was analyzed for urine osmolality (UOsm), color (UC), while the number of voids (void) was also recorded. Receiver Operating Characteristic (ROC) analysis was performed for UC, void, and combination of UC and void, to determine markers' diagnostic ability for detecting underhydration based on elevated UOsm (UOsm ≥ 800 mmol kg-1). RESULTS: Linear regression analysis revealed that UC was significantly associated with UOsm in both adults (R2 = 0.38; P < 0.001) and children (R2 = 0.45; P < 0.001). Void was significantly associated with UOsm in both adults (R2 = 0.13; P < 0.001) and children (R2 = 0.15; P < 0.001). In adults, when UC > 3 and void <7 were combined, the overall diagnostic ability for underhydration was 97% with sensitivity and specificity of 100% and 88%, respectively. In children, UC > 3 and void <5 had an overall diagnostic ability for underhydration of 89% with sensitivity and specificity of 100% and 62%, respectively. CONCLUSIONS: Urine color alone and the combination of urine color with void number can a valid and simple field-measure to detect underhydration based on elevated urine osmolality.

Hydration for health hypothesis: a narrative review of supporting evidence.

PURPOSE: An increasing body of evidence suggests that excreting a generous volume of diluted urine is associated with short- and long-term beneficial health effects, especially for kidney and metabolic function. However, water intake and hydration remain under-investigated and optimal hydration is poorly and inconsistently defined. This review tests the hypothesis that optimal chronic water intake positively impacts various aspects of health and proposes an evidence-based definition of optimal hydration. METHODS: Search strategy included PubMed and Google Scholar using relevant keywords for each health outcome, complemented by manual search of article reference lists and the expertise of relevant practitioners for each area studied. RESULTS: The available literature suggest the effects of increased water intake on health may be direct, due to increased urine flow or urine dilution, or indirect, mediated by a reduction in osmotically -stimulated vasopressin (AVP). Urine flow affects the formation of kidney stones and recurrence of urinary tract infection, while increased circulating AVP is implicated in metabolic disease, chronic kidney disease, and autosomal dominant polycystic kidney disease. CONCLUSION: In order to ensure optimal hydration, it is proposed that optimal total water intake should approach 2.5 to 3.5 L day-1 to allow for the daily excretion of 2 to 3 L of dilute (< 500 mOsm kg-1) urine. Simple urinary markers of hydration such as urine color or void frequency may be used to monitor and adjust intake.

Adiposity, psychomotor and behaviour outcomes of children born after maternal bariatric surgery.

BACKGROUND: Bariatric surgery before pregnancy can result in improved maternal fertility. However, long-term data on the consequences at childhood age are currently lacking. METHODS: EFFECTOR is a prospective cohort study of children (aged 4 to 11 years) born to mothers who underwent bariatric surgery (BS) before pregnancy (n = 36), controls with overweight/obesity (OW/OB) matched on pre-pregnancy BMI (n = 36) and normal weight controls (NL) (n = 35). We performed prospective collection of anthropometric data, data on psychomotor development, school functioning and behaviour (Strengths and Difficulties Questionnaire (SDQ), Child Behaviour Checklist (CBCL)). RESULTS: The children born after bariatric surgery (BS) presented with the highest body-weight SDS (0.70 vs 0.14 in OW/OB and -0.09 in NL; P = .006) and BMI SDS (0.47 vs -0.02 in OW/OB and -0.42 in NL; P = .01). A higher excess in body fat percentage and waist circumference SDS were found in the BS group (5.7 vs 1.4 in OW/OB and -0.1 in NL; P < .001 and 0.61 vs 0.16 in OW/OB and -0.15 in NL; P = .04). The SDQ questionnaires revealed a higher amount of overall problems in the BS offspring (11.1 vs 7.5 in OW/OB and 8.1 in NL; P = .03), with a higher externalizing score at the CBCL (52.0 vs 44.2 in OW/OB and 47.0 in NL; P = .03). CONCLUSION: Maternal bariatric surgery does not appear to protect the offspring for childhood overweight and obesity. Parents reported more behaviour problems in these children, especially externally of nature.

Understanding Attitudes to Change to Healthier Hydration Habits: The Case of High Sugar: Low Water Drinkers in Mexico.

Adults consuming sugar-sweetened beverages (SSBs) are at increased risk of becoming overweight/obese and developing lifestyle-related diseases. Furthermore, a low water intake is associated with increased health risks, such as CKD. These issues are especially pressing in Mexico where SSB intake is high. The present research aimed to describe the attitudes of Mexican adults who are considered high sugar-low water drinkers (HS-LWDs). HS-LWDs were defined as adults aged 18-45 years, drinking at least 2 servings (500 mL) of SSB/day and maximum 3 servings (750 mL) of water/day. The study included 2.858 HS-LWD (58% males) living in the urban area of Mexico City. Data were collected using an online, self-administered questionnaire. Bayesian approach was applied to analyze attitudes in life and towards drinking. Results showed that social aspects, such as sharing with friends and family and self-image, were the dominant attitudes in life. The main reason to choose a beverage was to get sensations, resulting in 2 axes, one was pleasure oriented and one was health oriented. Getting sensations was also a main driver to drink linked to a moment, together with self-image. The Bayesian network analysis demonstrated 5 attitude profiles, based on the most important attitudes defining each profile: mood and pleasure, self-image and body image, sharing and restoring, pleasure and energy, and health and success. This study allowed describing HS-LWD attitudes, in life and towards drinking. It constitutes a first step in understanding this target group's attitudes and behavior, offering potential recommendations for tailored interventions to promote the adoption of healthier drinking habits.

Hydration in Children: What Do We Know and Why Does it Matter?

In children, maintaining adequate fluid intake and hydration is important for physiological reasons and for the adoption of healthy, sustainable drinking habits. In the Liq.In7 cross-sectional surveys involving 6,469 children (4-17 years) from 13 countries, 60% of children did not meet the European Food Safety Authority (EFSA) adequate intake for water from fluids. Beyond fluid quantity, the quality of what children drink is important for health. In these surveys, the contribution of sugar-sweetened beverages and fruit juices to total fluid intake (TFI) in children exceeded that of water in 6 out of 13 countries. To assess the adequacy of children's fluid intake, urinary biomarkers of hydration such as urine osmolality, urine specific gravity, and urine color may be used. To date, while there are no widely accepted specific threshold values for urine concentration to define adequate hydration in children, the available literature suggests that many children have highly concentrated urine, indicating insufficient fluid intake. This is worrisome since studies have demonstrated a relationship between low fluid intake or insufficient hydration and cognitive performance in children. Furthermore, results of the Liq.In7 surveys showed that at school - where children spend a significant amount of time and require optimal cognitive performance - children drink only 14% of their TFI. Consequently, it is pertinent to better understand the barriers to drinking water at school and encourage the promotion of water intake through multicomponent interventions that combine educational, environmental, and behavioral aspects to support adequate hydration as well as optimal cognition in children.

Correction to: Challenges in the assessment of total fluid intake in children and adolescents: a discussion paper.

In the original publication of the article, a mistake was introduced in affiliation of Dr. Michael Nelson.

Challenges in the assessment of total fluid intake in children and adolescents: a discussion paper.

PURPOSE: In recent years, evidence has emerged about the importance of healthy fluid intake in children for physical and mental performance and health, and in the prevention of obesity. Accurate data on water intake are needed to inform researchers and policymakers and for setting dietary reference values. However, to date, there are few published data on fluid or water intakes in children. This is due partly to the fact that drinking water is not always reported in dietary surveys. The aim of this paper is to review the current status of the literature and highlight the challenges of assessing total fluid intake in children and adolescents. RESULTS: From the dietary assessment literature it is apparent that children present unique challenges to assessing intake due to ongoing cognitive capacity development, limited literacy skills, difficulties in estimating portion sizes and multiple caregivers during any 1 day making it difficult to track intakes. As such, many issues should be considered when assessing total fluid intakes in children or adolescents. Various methods to assess fluid intakes exist, each with its own strengths and weaknesses; the ultimate choice of method depends on the research question and resources available. Based on the literature review, it is apparent that if the research focus is to assess only fluid intake, a fluid-specific method, such as a diary or record, appears to be a feasible approach to provide an accurate estimate of intakes.

Fluid intake patterns of children and adolescents: results of six Liq.In7 national cross-sectional surveys.

PURPOSE: This study aimed to identify and characterize patterns of fluid intake in children and adolescents from six countries: Argentina, Brazil, China, Indonesia, Mexico and Uruguay. METHODS: Data on fluid intake volume and type amongst children (4-9 years; N = 1400) and adolescents (10-17 years; N = 1781) were collected using the validated 7-day fluid-specific record (Liq.In7 record). To identify relatively distinct clusters of subjects based on eight fluid types (water, milk and its derivatives, hot beverages, sugar-sweetened beverages (SSB), 100% fruit juices, artificial/non-nutritive sweetened beverages, alcoholic beverages, other beverages), a cluster analysis (partitioning around k-medoids algorithm) was used. Clusters were then characterized according to their socio-demographics and lifestyle indicators. RESULTS: The six interpretable clusters identified were: low drinkers-SSB (n 523), low drinkers-water and milk (n 615), medium mixed drinkers (n 914), high drinkers-SSB (n 513), high drinkers-water (n 352) and very high drinkers-water (n 264). Country of residence was the dominant characteristic, followed by socioeconomic level, in all six patterns. CONCLUSIONS: This analysis showed that consumption of water and SSB were the primary drivers of the clusters. In addition to country, socio-demographic and lifestyle factors played a role in determining the characteristics of each cluster. This information highlights the need to target interventions in particular populations aimed at changing fluid intake behavior and improving health in children and adolescents.

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.

Background: Mean daily water intake from fluids (WATER-FL) has proven to be difficult to measure because of a range of nonvalidated data collection techniques. Few questionnaires have been validated to estimate WATER-FL against self-reported diaries or urinary hydration markers, which may limit their objectivity.Objectives: The goals of this investigation were 1) to assess the validity of a 7-d fluid record (7dFLR) to measure WATER-FL (WATER-FL-7dFLR) through comparison with WATER-FL as calculated by measuring deuterium oxide (D2O) disappearance (WATER-FL-D2O), and 2) to evaluate the reliability of the 7dFLR in measuring WATER-FL.Methods: Participants [n = 96; 51% female; mean ± SD age: 41 ± 14 y; mean ± SD body mass index (in kg/m2): 26.2 ± 5.1] completed body water turnover analysis over 3 consecutive weeks. They completed the 7dFLR and food diaries during weeks 2 and 4 of the observation. The records were entered into nutritional software to determine the water content of all foods and fluids consumed. WATER-FL-D2O was calculated from water turnover (via the D2O dilution method), minus water from food and metabolic water. The agreement between the 2 methods of determining WATER-FL were compared according to a Bland-Altman plot at week 2. The test-retest reliability of 7dFLR between weeks 2 and 4 was assessed via intraclass correlation (ICC).Results: The mean ± SD difference between WATER-FL-7dFLR and WATER-FL-D2O was -131 ± 845 mL/d. In addition, no bias was observed (F[1,94] = 0.484; R2 = 0.006; P = 0.488). When comparing WATER-FL-7dFLR from weeks 2 and 4, no significant difference (mean ± SD difference: 71 ± 75 mL/d; t[79] = 0.954; P = 0.343) and an ICC of 0.85 (95% CI: 0.77, 0.90) was observed.Conclusions: The main findings of this study were that the use of the 7dFLR is an effective and reliable method to estimate WATER-FL in adults. This style of questionnaire may be extremely helpful for collecting water intake data for large-scale epidemiologic studies.

Two Liters a Day Keep the Doctor Away? Considerations on the Pathophysiology of Suboptimal Fluid Intake in the Common Population.

Suboptimal fluid intake may require enhanced release of antidiuretic hormone (ADH) or vasopressin for the maintenance of adequate hydration. Enhanced copeptin levels (reflecting enhanced vasopressin levels) in 25% of the common population are associated with enhanced risk of metabolic syndrome with abdominal obesity, type 2 diabetes, hypertension, coronary artery disease, heart failure, vascular dementia, cognitive impairment, microalbuminuria, chronic kidney disease, inflammatory bowel disease, cancer, and premature mortality. Vasopressin stimulates the release of glucocorticoids which in turn up-regulate the serum- and glucocorticoid-inducible kinase 1 (SGK1). Moreover, dehydration upregulates the transcription factor NFAT5, which in turn stimulates SGK1 expression. SGK1 is activated by insulin, growth factors and oxidative stress via phosphatidylinositide-3-kinase, 3-phosphoinositide-dependent kinase PDK1 and mTOR. SGK1 is a powerful stimulator of Na+/K+-ATPase, carriers (e.g. the Na+,K+,2Cl- cotransporter NKCC, the NaCl cotransporter NCC, the Na+/H+ exchanger NHE3, and the Na+ coupled glucose transporter SGLT1), and ion channels (e.g. the epithelial Na+ channel ENaC, the Ca2+ release activated Ca2+ channel Orai1 with its stimulator STIM1, and diverse K+ channels). SGK1 further participates in the regulation of the transcription factors nuclear factor kappa-B NFκB, p53, cAMP responsive element binding protein (CREB), activator protein-1, and forkhead transcription factor FKHR-L1 (FOXO3a). Enhanced SGK1 activity fosters the development of hypertension, obesity, diabetes, thrombosis, stroke, inflammation including inflammatory bowel disease and autoimmune disease, cardiac fibrosis, proteinuria, renal failure as well as tumor growth. The present brief review makes the case that suboptimal fluid intake in the common population may enhance vasopressin and glucocorticoid levels thus up-regulating SGK1 expression and favouring the development of SGK1 related pathologies.

Pregnant and Breastfeeding Women: Drinking for Two?

The primary aim of this cross-sectional survey was to assess the total fluid intake (TFI; sum of drinking water and all other fluids) and the intake of water and all other types of beverages in a sample of pregnant and breastfeeding women representative of Java-Island, Indonesia. Therefore, 299 pregnant and 296 breastfeeding women completed a 7-day fluid-specific record. A secondary aim was to estimate the total water intake (TWI; sum of water from fluids and food moisture), and one 24-h recall was performed to determine water intake from food moisture. The median TFI of pregnant and breastfeeding women were 2,250 (1,800-2,800) and 2,360 (1,954-2,968) mL/day, respectively. The largest contributor to TFI was water (72 and 77% for pregnant/breastfeeding women, respectively). Pregnant women to the extent of 42% and 54% of breastfeeding women did not reach the adequate intake (AI) of water from fluids. In pregnant and breastfeeding women, the median water intake from foods was 592 and 613 mL/day, representing 21 and 20% of TWI. Concluding that a high proportion of the pregnant and breastfeeding subjects did not reach the AI of water from fluid, it seems important to put in place actions such as providing education materials and ensuring access to safe water. Moreover, future surveys should dedicate attention to the assessment of fluid intake and hydration status among pregnant and breastfeeding women in other countries.

Increasing water intake in pre-school children with unhealthy drinking habits: A year-long controlled longitudinal field experiment assessing the impact of information, water affordance, and social regulation.

OBJECTIVE: We investigated the effect of three interventions to increase the plain water consumption of children with unhealthy drinking habits, with an innovative approach combining the three layers of Installation Theory: embodied competences, affordances and social regulation. METHODS: 334 preschool children and their carers were allocated to three interventions: Control (control): no intervention, Information (info): online coaching sessions on water health benefits aiming at modifying embodied competences (knowledge), Information + Water Affordance (info + w): the same plus home delivery of small bottles of water. After three months, half of the info and info + w subjects were allocated to Social Regulation (+social) (on-line discussion forum) or no further intervention (-social). Intake of plain water and all other fluid types of the children were recorded by the carers 6 times over a year using an online 7-day fluid-specific dietary record. RESULTS: Over 1 year, all groups significantly increased daily water consumption by 3.0-7.8 times (+118 to +222 mL). Info + w + social and Info-social generated the highest increase in plain water intake after one year compared to baseline, by 7.8 times (+216 mL) and 6.7 times (+222 mL) respectively; both significantly exceeded the control (3.0 times, +118 mL), whilst the effect of info + w-social (5.0 times, +158 mL) and info + social (5.3 times, +198 mL) did not differ from that of control. All groups saw a decrease of sweetened beverages intake, again with info + w + social generating the largest decrease (-27%; -172 mL). No changes in other fluids or total fluid intake were observed. CONCLUSIONS: Sustainable increased water consumption can be achieved in children with unhealthy drinking habits by influencing representations, changing material affordances, and providing social regulation. Combining the three provided the strongest effect as predicted by Installation Theory.

Urine color as an indicator of urine concentration in pregnant and lactating women.

AIM: Urine concentration measured via osmolality (U OSM) and specific gravity (U SG) reflects the adequacy of daily fluid intake, which has important relationships to health in pregnant (PREG) and lactating (LACT) women. Urine color (U COL) may be a practical, surrogate marker for whole-body hydration status. PURPOSE: To determine whether U COL was a valid measure of urine concentration in PREG and LACT, and pair-matched non-pregnant, non-lactating control women (CON). METHODS: Eighteen PREG/LACT (age 31 ± 1 years, pre-pregnancy BMI 24.3 ± 5.9 kg m-2) and eighteen CON (age 29 ± 4 years, BMI 24.1 ± 3.7 kg m-2) collected 24-h and single-urine samples on specified daily voids at five time points (15 ± 2, 26 ± 1, and 37 ± 1 weeks gestation, 3 ± 1 and 9 ± 1 weeks postpartum during lactation; CON visits were separated by similar time intervals) for measurement of 24-h U OSM, U SG, and U COL and single-sample U OSM and U COL. RESULTS: Twenty-four-hour U COL was significantly correlated with 24-h U OSM (r = 0.6085-0.8390, P < 0.0001) and 24-h U SG (r = 0.6213-0.8985, P < 0.0001) in all groups. A 24-h U COL ≥ 4 (AUC = 0.6848-0.9513, P < 0.05) and single-sample U COL ≥ 4 (AUC = 0.9094-0.9216, P < 0.0001) indicated 24-h U OSM ≥ 500 mOsm kg-1 (representing inadequate fluid intake) in PREG, LACT, and CON. CONCLUSIONS: Urine color was a valid marker of urine concentration in all groups. Thus, PREG, LACT, and CON can utilize U COL to monitor their daily fluid balance. Women who present with a U COL ≥ 4 likely have a U OSM ≥ 500 mOsm kg-1 and should increase fluid consumption to improve overall hydration status.

Relationships between hydration biomarkers and total fluid intake in pregnant and lactating women.

INTRODUCTION: Previous research established significant relationships between total fluid intake (TFI) and urinary biomarkers of the hydration process in free-living males and females; however, the nature of this relationship is not known for pregnant (PREG) and lactating (LACT) women. PURPOSE: To determine the relationship between urinary and hematological hydration biomarkers with TFI in PREG and LACT. METHODS: Eighteen PREG/LACT (age: 31 ± 3 years, pre-pregnancy BMI: 24.26 ± 5.85 kg m-2) collected 24-h urine samples, recorded TFI, and provided a blood sample at 5 time points (15 ± 2, 26 ± 1, 37 ± 1 weeks gestation, 3 ± 1 and 9 ± 1 weeks postpartum during lactation); 18 pair-matched non-pregnant (NP), non-lactating (NL) women (age: 29 ± 4 years, BMI: 24.1 ± 3.7 kg m-2) provided samples at similar time intervals. Twenty-four-hour urine volume (U VOL), osmolality (U OSM), specific gravity (U SG), and color (U COL) were measured. Hematocrit, serum osmolality (S OSM), and serum total protein (S TP) were measured in blood. RESULTS: Significant relationships were present between TFI and urinary biomarkers in all women (P < 0.004); these relationships were not different between PREG and NP, and LACT and NL, except U VOL in PREG (P = 0.0017). No significant relationships between TFI and hematological biomarkers existed (P > 0.05). CONCLUSION: Urinary biomarkers of hydration, but not hematological biomarkers, have a strong relationship with TFI in PREG, LACT, NP, and NL women. These data suggest that urinary biomarkers of hydration reflect TFI during pregnancy and breast-feeding.

Fluid Intake of Pregnant and Breastfeeding Women in Indonesia: A Cross-Sectional Survey with a Seven-Day Fluid Specific Record.

During pregnancy and lactation, the adequate intake (AI) for total water intake is increased. This cross-sectional survey aimed to assess Total Fluid Intake (TFI; sum of drinking water and all other fluids) of 300 pregnant and 300 breastfeeding women in Indonesia. A seven-day fluid specific record was used to assess TFI. Mean TFI of pregnant and breastfeeding women were 2332 ± 746 mL/day and 2525 ± 843 mL/day, respectively. No significant difference in TFI between pregnancy trimesters was observed, while TFI of women breastfeeding for 12-24 months postpartum (2427 ± 955 mL/day) was lower than that of the two other groups (0-5 months: 2607 ± 754 mL/day; 6-11 months: 2538 ± 807 mL/day, respectively). Forty-two and 54% of the pregnant and breastfeeding subjects, respectively, did not reach the AI of water from fluids. These AI were actually known by only 14% and 23% of the pregnant and breastfeeding subjects. However, having the knowledge about the AI did not increase the odds of reaching the AI. Concluding that a high proportion of the pregnant and breastfeeding subjects did not reach the AI of water from fluid, it seems pertinent to further assess the fluid intake, as well as their hydration status, in other countries.

Drinking Water Intake Is Associated with Higher Diet Quality among French Adults.

This study aimed to examine the association between drinking water intake and diet quality, and to analyse the adherence of French men and women to the European Food Safety Authority 2010 Adequate Intake (EFSA AI). A representative sample of French adults (≥18) from the Individual and National Survey on Food Consumption (INCA2) was classified, by sex, into small, medium, and large drinking water consumers. Diet quality was assessed with several nutritional indices (mean adequacy ratio (MAR), mean excess ratio (MER), probability of adequate intakes (PANDiet), and solid energy density (SED)). Of the total sample, 72% of men and 46% of women were below the EFSA AI. This percentage of non-adherence decreased from the small to the large drinking water consumers (from 95% to 34% in men and from 81% to 9% in women). For both sexes, drinking water intake was associated with higher diet quality (greater MAR and PANDiet). This association remained significant independently of socio-economic status for women only. Low drinking water consumers did not compensate with other sources (beverages and food moisture) and a high drinking water intake was not a guarantee for reaching the EFSA AI, meaning that increasing consumption of water should be encouraged in France.

Contribution of Water from Food and Fluids to Total Water Intake: Analysis of a French and UK Population Surveys.

Little has been published on the contribution of food moisture (FM) to total water intake (TWI); therefore, the European Food Safety Authority assumed FM to contribute 20%-30% to TWI. The aim of the present analysis was to estimate and compare TWI, the percentage of water from FM and from fluids in population samples of France and UK. Data from 2 national nutrition surveys (Enquête Comportements et Consommations Alimentaires en France (CCAF) 2013 and the National Diet and Nutrition Survey (NDNS) 2008/2009-2011/2012) were analyzed for TWI and the contribution of water from FM and fluids. Children and adults TWI were significantly lower in France than in the UK. The contribution of water from foods was lower in the UK than in France (27% vs. 36%). As TWI increased, the proportion of water from fluids increased, suggesting that low drinkers did not compensate by increasing intake of water-rich foods. In addition, 80%-90% of the variance in TWI was explained by differences in water intake from fluids. More data on the contribution of FM to TWI is needed to develop more robust dietary recommendations on TWI and guidance on fluid intake for the general public.

Fluid Intake and Vasopressin: Connecting the Dots.

In the last decade, cross-sectional and multiple cohort studies have associated total fluid intake or water intake with the risk for chronic kidney disease (CKD) and even the risk of developing hyperglycemia. Urine biomarkers have also been linked to the risk of CKD and lithiasis, and these biomarkers respond quickly to variations in fluid intake. High circulating copeptin levels, a surrogate marker of arginine vasopressin, have been associated with metabolic syndrome, renal dysfunction and increased risk for diabetes mellitus, cardiovascular disease and death. The aim of this paper was to explore how the various findings on water intake, hydration and health are interconnected, to highlight current gaps in our understanding and to propose a model that links water intake, homeostatic mechanisms to maintain water balance and health outcomes. Since plasma copeptin and vasopressin have been demonstrated to be sensitive to changes in water intake, inversely associated with 24-hour urine volume, and associated with urine biomarkers and fluid intake, vasopressin is proposed as the central player in this theoretical physiological model.