Editorial

2 pages, 171 KiB

Open AccessEditorial

Water Intake, Body Water Regulation and Health

by Evan C. Johnson and William M. Adams

Nutrients 2020, 12(3), 702; https://doi.org/10.3390/nu12030702 - 06 Mar 2020

Cited by 6 | Viewed by 5864

The biological feedback provided by human water intake upon our physiology is grossly under-investigated [...] Full article

(This article belongs to the Special Issue Water Intake, Body Water Regulation and Health)

Research

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10 pages, 1280 KiB

Open AccessArticle

High Hydration Factor in Older Hispanic-American Adults: Possible Implications for Accurate Body Composition Estimates

by Rogelio González-Arellanes, Rene Urquidez-Romero, Alejandra Rodríguez-Tadeo, Julián Esparza-Romero, Rosa-Olivia Méndez-Estrada, Erik Ramírez-López, Alma-Elizabeth Robles-Sardin, Bertha-Isabel Pacheco-Moreno and Heliodoro Alemán-Mateo

Nutrients 2019, 11(12), 2897; https://doi.org/10.3390/nu11122897 - 29 Nov 2019

Cited by 8 | Viewed by 2959

Abstract

Age- and obesity-related body composition changes could influence the hydration factor (HF) and, as a result, body composition estimates derived from hydrometry. The aim of the present study was to compare the HF in older Hispanic-American adults to some published values. This cross-sectional [...] Read more.

Age- and obesity-related body composition changes could influence the hydration factor (HF) and, as a result, body composition estimates derived from hydrometry. The aim of the present study was to compare the HF in older Hispanic-American adults to some published values. This cross-sectional study included a sample of 412 subjects, men and women, aged ≥60 years from northern Mexico. HF values were calculated based on the ratio of total body water-using the deuterium dilution technique-to fat-free mass, derived from the four-compartment model. The mean HF value for the total sample (0.748 ± 0.034) was statistically (p ≤ 0.01) higher than the traditionally assumed value of 0.732 derived from chemical analysis, the “grand mean’’ value of 0.725 derived from in vivo methods, and the 0.734 value calculated for older French adults via the three-compartment model. The HF of the older women did not differ across the fat mass index categories, but in men the obese group was lower than the normal and excess fat groups. The hydration factor calculated for the total sample of older Hispanic-American people is higher than the HF values reported in the literature. Therefore, the indiscriminate use of these assumed values could produce inaccurate body composition estimates in older Hispanic-American people. Full article

(This article belongs to the Special Issue Water Intake, Body Water Regulation and Health)

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13 pages, 777 KiB

Open AccessArticle

The Utility of Thirst as a Measure of Hydration Status Following Exercise-Induced Dehydration

by William M. Adams, Lesley W. Vandermark, Luke N. Belval and Douglas J. Casa

Nutrients 2019, 11(11), 2689; https://doi.org/10.3390/nu11112689 - 07 Nov 2019

Cited by 16 | Viewed by 4961

Abstract

The purpose of this study was to examine the perception of thirst as a marker of hydration status following prolonged exercise in the heat. Twelve men (mean ± SD; age, 23 ± 4 y; body mass, 81.4 ± 9.9 kg; height, 182 ± [...] Read more.

The purpose of this study was to examine the perception of thirst as a marker of hydration status following prolonged exercise in the heat. Twelve men (mean ± SD; age, 23 ± 4 y; body mass, 81.4 ± 9.9 kg; height, 182 ± 9 cm; body fat, 14.3% ± 4.7%) completed two 180 min bouts of exercise on a motorized treadmill in a hot environment (35.2 ± 0.6 °C; RH, 30.0 ± 5.4%), followed by a 60 min recovery period. Participants completed a euhydrated (EUH) and hypohydrated (HYPO) trial. During recovery, participants were randomly assigned to either fluid replacement (EUH_FL and HYPO_FL; 10 min ad libitum consumption) or no fluid replacement (EUH_NF and HYPO_NF). Thirst was measured using both a nine-point scale and separate visual analog scales. The percent of body mass loss (%BML) was significantly greater immediately post exercise in HYPO (HYPO_FL, 3.0% ± 1.2%; HYPO_NF, 2.6% ± 0.6%) compared to EUH (EUH_FL, 0.2% ± 0.7%; EUH_NF, 0.6% ± 0.5%) trials (p < 0.001). Following recovery, there were no differences in %BML between HYPO_FL and HYPO_NF (p > 0.05) or between EUH_FL and EUH_NF (p > 0.05). Beginning at minute 5 during the recovery period, thirst perception was significantly greater in HYPO_NF than EUH_FL, EUH_NF, and HYPO_FL (p < 0.05). A 10 min, ad libitum consumption of fluid post exercise when hypohydrated (%BML > 2%), negated differences in perception of thirst between euhydrated and hypohydrated trials. These results represent a limitation in the utility of thirst in guiding hydration practices. Full article

(This article belongs to the Special Issue Water Intake, Body Water Regulation and Health)

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11 pages, 3862 KiB

Open AccessArticle

Unexplained Variance in Hydration Study

by Colleen X. Muñoz and Michael Wininger

Nutrients 2019, 11(8), 1828; https://doi.org/10.3390/nu11081828 - 07 Aug 2019

Cited by 2 | Viewed by 3246

Abstract

With the collection of water-intake data, the National Health and Nutrition Examination Survey (NHANES) is becoming an increasingly popular resource for large-scale inquiry into human hydration. However, are we leveraging this resource properly? We sought to identify the opportunities and limitations inherent in [...] Read more.

With the collection of water-intake data, the National Health and Nutrition Examination Survey (NHANES) is becoming an increasingly popular resource for large-scale inquiry into human hydration. However, are we leveraging this resource properly? We sought to identify the opportunities and limitations inherent in hydration-related inquiry within a commonly studied database of hydration and nutrition. We also sought to critically review models published from this dataset. We reproduced two models published from the NHANES dataset, assessing the goodness of fit through conventional means (proportion of variance, R²). We also assessed model sensitivity to parameter configuration. Models published from the NHANES dataset typically yielded a very low goodness of fit R² < 0.15. A reconfiguration of variables did not substantially improve model fit, and the goodness of fit of models published from the NHANES dataset may be low. Database-driven inquiry into human hydration requires the complete reporting of model diagnostics in order to fully contextualize findings. There are several emergent opportunities to potentially increase the proportion of explained variance in the NHANES dataset, including novel biomarkers, capturing situational variables (meteorology, for example), and consensus practices for adjustment of co-variates. Full article

(This article belongs to the Special Issue Water Intake, Body Water Regulation and Health)

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10 pages, 979 KiB

Open AccessArticle

Osmolality of Commercially Available Oral Rehydration Solutions: Impact of Brand, Storage Time, and Temperature

by Kurt J. Sollanek, Robert W. Kenefick and Samuel N. Cheuvront

Nutrients 2019, 11(7), 1485; https://doi.org/10.3390/nu11071485 - 29 Jun 2019

Cited by 6 | Viewed by 5236

Abstract

Oral rehydration solutions (ORS) are specifically formulated with an osmolality to optimize fluid absorption. However, it is unclear how many ORS products comply with current World Health Organization (WHO) osmolality guidelines and the osmotic shelf-life stability is not known. Therefore, the purpose of [...] Read more.

Oral rehydration solutions (ORS) are specifically formulated with an osmolality to optimize fluid absorption. However, it is unclear how many ORS products comply with current World Health Organization (WHO) osmolality guidelines and the osmotic shelf-life stability is not known. Therefore, the purpose of this investigation was to examine the within and between ORS product osmolality variation in both pre-mixed and reconstituted powders. Additionally, the osmotic stability was examined over time. The osmolality of five different pre-mixed solutions and six powdered ORS products were measured. Pre-mixed solutions were stored at room temperatures and elevated temperatures (31 °C) for two months to examine osmotic shelf stability. Results demonstrated that only one pre-mixed ORS product was in compliance with the current guidelines both before and after the prolonged storage. Five of the six powdered ORS products were in compliance with minimal inter-packet variation observed within the given formulations. This investigation demonstrates that many commercially available pre-mixed ORS products do not currently adhere to the WHO recommended osmolality guidelines. Additionally, due to the presence of particular sugars and possibly other ingredients, the shelf-life stability of osmolality for certain ORS products may be questioned. These findings should be carefully considered in the design of future ORS products. Full article

(This article belongs to the Special Issue Water Intake, Body Water Regulation and Health)

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Review

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25 pages, 1669 KiB

Open AccessReview

The Potential for Renal Injury Elicited by Physical Work in the Heat

by Zachary J. Schlader, David Hostler, Mark D. Parker, Riana R. Pryor, James W. Lohr, Blair D. Johnson and Christopher L. Chapman

Nutrients 2019, 11(9), 2087; https://doi.org/10.3390/nu11092087 - 04 Sep 2019

Cited by 52 | Viewed by 8465

Abstract

An epidemic of chronic kidney disease (CKD) is occurring in laborers who undertake physical work in hot conditions. Rodent data indicate that heat exposure causes kidney injury, and when this injury is regularly repeated it can elicit CKD. Studies in humans demonstrate that [...] Read more.

An epidemic of chronic kidney disease (CKD) is occurring in laborers who undertake physical work in hot conditions. Rodent data indicate that heat exposure causes kidney injury, and when this injury is regularly repeated it can elicit CKD. Studies in humans demonstrate that a single bout of exercise in the heat increases biomarkers of acute kidney injury (AKI). Elevations in AKI biomarkers in this context likely reflect an increased susceptibility of the kidneys to AKI. Data largely derived from animal models indicate that the mechanism(s) by which exercise in the heat may increase the risk of AKI is multifactorial. For instance, heat-related reductions in renal blood flow may provoke heterogenous intrarenal blood flow. This can promote localized ischemia, hypoxemia and ATP depletion in renal tubular cells, which could be exacerbated by increased sodium reabsorption. Heightened fructokinase pathway activity likely exacerbates ATP depletion occurring secondary to intrarenal fructose production and hyperuricemia. Collectively, these responses can promote inflammation and oxidative stress, thereby increasing the risk of AKI. Equivalent mechanistic evidence in humans is lacking. Such an understanding could inform the development of countermeasures to safeguard the renal health of laborers who regularly engage in physical work in hot environments. Full article

(This article belongs to the Special Issue Water Intake, Body Water Regulation and Health)

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24 pages, 326 KiB

Open AccessReview

Pediatric Thermoregulation: Considerations in the Face of Global Climate Change

by Caroline J. Smith

Nutrients 2019, 11(9), 2010; https://doi.org/10.3390/nu11092010 - 26 Aug 2019

Cited by 56 | Viewed by 8427

Abstract

Predicted global climate change, including rising average temperatures, increasing airborne pollution, and ultraviolet radiation exposure, presents multiple environmental stressors contributing to increased morbidity and mortality. Extreme temperatures and more frequent and severe heat events will increase the risk of heat-related illness and associated [...] Read more.

Predicted global climate change, including rising average temperatures, increasing airborne pollution, and ultraviolet radiation exposure, presents multiple environmental stressors contributing to increased morbidity and mortality. Extreme temperatures and more frequent and severe heat events will increase the risk of heat-related illness and associated complications in vulnerable populations, including infants and children. Historically, children have been viewed to possess inferior thermoregulatory capabilities, owing to lower sweat rates and higher core temperature responses compared to adults. Accumulating evidence counters this notion, with limited child–adult differences in thermoregulation evident during mild and moderate heat exposure, with increased risk of heat illness only at environmental extremes. In the context of predicted global climate change, extreme environmental temperatures will be encountered more frequently, placing children at increased risk. Thermoregulatory and overall physiological strain in high temperatures may be further exacerbated by exposure to/presence of physiological and environmental stressors including pollution, ultraviolet radiation, obesity, diabetes, associated comorbidities, and polypharmacy that are more commonly occurring at younger ages. The aim of this review is to revisit fundamental differences in child–adult thermoregulation in the face of these multifaceted climate challenges, address emerging concerns, and emphasize risk reduction strategies for the health and performance of children in the heat. Full article

(This article belongs to the Special Issue Water Intake, Body Water Regulation and Health)

19 pages, 306 KiB

Open AccessReview

Deuterium-Depleted Water Influence on the Isotope ²H/¹H Regulation in Body and Individual Adaptation

by Alexander Basov, Liliia Fedulova, Mikhail Baryshev and Stepan Dzhimak

Nutrients 2019, 11(8), 1903; https://doi.org/10.3390/nu11081903 - 15 Aug 2019

Cited by 40 | Viewed by 13920

Abstract

This review article presents data about the influence of deuterium-depleted water (DDW) on biological systems. It is known that the isotope abundances of natural and bottled waters are variable worldwide. That is why different drinking rations lead to changes of stable isotopes content [...] Read more.

This review article presents data about the influence of deuterium-depleted water (DDW) on biological systems. It is known that the isotope abundances of natural and bottled waters are variable worldwide. That is why different drinking rations lead to changes of stable isotopes content in body water fluxes in human and animal organisms. Also, intracellular water isotope ratios in living systems depends on metabolic activity and food consumption. We found the ²H/¹H gradient in human fluids (δ²H _saliva >> δ²H _{blood plasma} > δ²H_{breast milk}), which decreases significantly during DDW intake. Moreover, DDW induces several important biological effects in organism (antioxidant, metabolic detoxification, anticancer, rejuvenation, behavior, etc.). Changing the isotope ²H/¹H gradient from “²H _{blood plasma} > δ²H _{visceral organs}” to “δ²H _{blood plasma} << δ²H _{visceral organs}” via DDW drinking increases individual adaptation by isotopic shock. The other possible mechanisms of long-term adaptation is DDW influence on the growth rate of cells, enzyme activity and cellular energetics (e.g., stimulation of the mitochondrion activity). In addition, DDW reduces the number of single-stranded DNA breaks and modifies the miRNA profile. Full article

(This article belongs to the Special Issue Water Intake, Body Water Regulation and Health)

21 pages, 720 KiB

Open AccessFeature PaperReview

Hydration Status and Cardiovascular Function

by Joseph C. Watso and William B. Farquhar

Nutrients 2019, 11(8), 1866; https://doi.org/10.3390/nu11081866 - 11 Aug 2019

Cited by 63 | Viewed by 20324

Abstract

Hypohydration, defined as a state of low body water, increases thirst sensations, arginine vasopressin release, and elicits renin–angiotensin–aldosterone system activation to replenish intra- and extra-cellular fluid stores. Hypohydration impairs mental and physical performance, but new evidence suggests hypohydration may also have deleterious effects [...] Read more.

Hypohydration, defined as a state of low body water, increases thirst sensations, arginine vasopressin release, and elicits renin–angiotensin–aldosterone system activation to replenish intra- and extra-cellular fluid stores. Hypohydration impairs mental and physical performance, but new evidence suggests hypohydration may also have deleterious effects on cardiovascular health. This is alarming because cardiovascular disease is the leading cause of death in the United States. Observational studies have linked habitual low water intake with increased future risk for adverse cardiovascular events. While it is currently unclear how chronic reductions in water intake may predispose individuals to greater future risk for adverse cardiovascular events, there is evidence that acute hypohydration impairs vascular function and blood pressure (BP) regulation. Specifically, acute hypohydration may reduce endothelial function, increase sympathetic nervous system activity, and worsen orthostatic tolerance. Therefore, the purpose of this review is to present the currently available evidence linking acute hypohydration with altered vascular function and BP regulation. Full article

(This article belongs to the Special Issue Water Intake, Body Water Regulation and Health)

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14 pages, 2366 KiB

Open AccessReview

Of Mice and Men—The Physiology, Psychology, and Pathology of Overhydration

by Tamara Hew-Butler, Valerie Smith-Hale, Alyssa Pollard-McGrandy and Matthew VanSumeren

Nutrients 2019, 11(7), 1539; https://doi.org/10.3390/nu11071539 - 07 Jul 2019

Cited by 19 | Viewed by 21849

Abstract

The detrimental effects of dehydration, to both mental and physical health, are well-described. The potential adverse consequences of overhydration, however, are less understood. The difficulty for most humans to routinely ingest ≥2 liters (L)—or “eight glasses”—of water per day highlights the likely presence [...] Read more.

The detrimental effects of dehydration, to both mental and physical health, are well-described. The potential adverse consequences of overhydration, however, are less understood. The difficulty for most humans to routinely ingest ≥2 liters (L)—or “eight glasses”—of water per day highlights the likely presence of an inhibitory neural circuit which limits the deleterious consequences of overdrinking in mammals but can be consciously overridden in humans. This review summarizes the existing data obtained from both animal (mostly rodent) and human studies regarding the physiology, psychology, and pathology of overhydration. The physiology section will highlight the molecular strength and significance of aquaporin-2 (AQP2) water channel downregulation, in response to chronic anti-diuretic hormone suppression. Absence of the anti-diuretic hormone, arginine vasopressin (AVP), facilitates copious free water urinary excretion (polyuria) in equal volumes to polydipsia to maintain plasma tonicity within normal physiological limits. The psychology section will highlight reasons why humans and rodents may volitionally overdrink, likely in response to anxiety or social isolation whereas polydipsia triggers mesolimbic reward pathways. Lastly, the potential acute (water intoxication) and chronic (urinary bladder distension, ureter dilation and hydronephrosis) pathologies associated with overhydration will be examined largely from the perspective of human case reports and early animal trials. Full article

(This article belongs to the Special Issue Water Intake, Body Water Regulation and Health)

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25 pages, 2582 KiB

Open AccessReview

Water Intake, Water Balance, and the Elusive Daily Water Requirement

by Lawrence E. Armstrong and Evan C. Johnson

Nutrients 2018, 10(12), 1928; https://doi.org/10.3390/nu10121928 - 05 Dec 2018

Cited by 110 | Viewed by 40072

Abstract

Water is essential for metabolism, substrate transport across membranes, cellular homeostasis, temperature regulation, and circulatory function. Although nutritional and physiological research teams and professional organizations have described the daily total water intakes (TWI, L/24h) and Adequate Intakes (AI) of children, women, and men, [...] Read more.

Water is essential for metabolism, substrate transport across membranes, cellular homeostasis, temperature regulation, and circulatory function. Although nutritional and physiological research teams and professional organizations have described the daily total water intakes (TWI, L/24h) and Adequate Intakes (AI) of children, women, and men, there is no widespread consensus regarding the human water requirements of different demographic groups. These requirements remain undefined because of the dynamic complexity inherent in the human water regulatory network, which involves the central nervous system and several organ systems, as well as large inter-individual differences. The present review analyzes published evidence that is relevant to these issues and presents a novel approach to assessing the daily water requirements of individuals in all sex and life-stage groups, as an alternative to AI values based on survey data. This empirical method focuses on the intensity of a specific neuroendocrine response (e.g., plasma arginine vasopressin (AVP) concentration) employed by the brain to regulate total body water volume and concentration. We consider this autonomically-controlled neuroendocrine response to be an inherent hydration biomarker and one means by which the brain maintains good health and optimal function. We also propose that this individualized method defines the elusive state of euhydration (i.e., water balance) and distinguishes it from hypohydration. Using plasma AVP concentration to analyze multiple published data sets that included both men and women, we determined that a mild neuroendocrine defense of body water commences when TWI is ˂1.8 L/24h, that 19–71% of adults in various countries consume less than this TWI each day, and consuming less than the 24-h water AI may influence the risk of dysfunctional metabolism and chronic diseases. Full article

(This article belongs to the Special Issue Water Intake, Body Water Regulation and Health)

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