for mice with unlimited access to water, what is the ratio of urine osmolarity to blood osmolarity?

While associations exist between water, hydration, and disease hazard, inquiry quantifying the dose-response effect of water on health is express. Thus, the water intake necessary to maintain optimal hydration from a physiological and health standpoint remains unclear. The aim of this analysis was to derive a 24 h urine osmolality (U_Osm) threshold that would provide an index of "optimal hydration," sufficient to compensate h2o losses and also be biologically significant relative to the gamble of affliction. Ninety-five adults (31.5 ± iv.3 years, 23.2 ± two.7 kg·one thousand⁻²) nerveless 24 h urine, provided morning claret samples, and completed nutrient and fluid intake diaries over iii consecutive weekdays. A U_Osm threshold was derived using three approaches, taking into account European dietary reference values for water; total fluid intake, and urine volumes associated with reduced gamble for lithiasis and chronic kidney disease and plasma vasopressin concentration. The amass of these approaches advise that a 24 h urine osmolality ≤500 mOsm·kg⁻¹ may be a uncomplicated indicator of optimal hydration, representing a full daily fluid intake adequate to compensate for daily losses, ensure urinary output sufficient to reduce the risk of urolithiasis and renal function turn down, and avoid elevated plasma vasopressin concentrations mediating the increased antidiuretic endeavour.

1. Introduction

Hydration is a dynamic residuum between water intake and loss, and trunk water balance is maintained through both behavioral and physiological responses. Water gains come virtually entirely from fluids and h2o in food, equally metabolic h2o accounts for only a minor fraction of daily h2o gain. Adequate intakes representing in fact population median consumption have been reported [ane, two]; however, the intake necessary to maintain optimal hydration from a physiological and health standpoint is all the same unknown. This is in function considering although h2o is essential to sustain life and normal physiological functions, inquiry quantifying the dose-response effect of h2o on health is very limited. Relationships betwixt water and wellness outcomes are difficult to assess. Trunk h2o needs are highly private and depend upon body composition and body size, nutrition-related osmotic load, physical activity and fitness level, and other factors such as climate, environment, and disease. Moreover, accurately measuring water intake is difficult, especially over long periods of fourth dimension, and relatively piffling research has focused on boilerplate adults with mostly sedentary lifestyles and occupations [3].

Despite the challenges to linking h2o intake to health, the bachelor testify suggests that bereft water intake is linked to some long-term health issues. Specifically, recent studies linking h2o intake and disease advise a relationship between water, hydration, and recurrent kidney stone disease (urolithiasis) [4–6], chronic kidney disease [seven–9], blood glucose regulation [10], and cardiovascular events [xi]. Collectively, these observations provide preliminary evidence that daily h2o intake in a higher place the minimum which is physiologically necessary to maintain full body h2o may confer additional benefits above simply maintaining total trunk water. Information technology can therefore be argued that truly adequate h2o intake is one which replaces daily losses, maintains total body water, and provides relative hazard reduction for the development of various long-term pathologies linked to low water intake. However, considering big interindividual differences in h2o needs, there is a need for a quantitative measurement, a physiological index or biomarker that would allow individuals to assess the capability of their daily water intake.

The physiological regulation of h2o rest is dynamic and complex, and biomarkers in plasma and urine have been unremarkably used to assess hydration. Plasma osmolality is a biomarker sensitive to acute dehydration [12, 13], but it is maintained within a narrow range across a wide spectrum of daily fluid intake volumes [2, 14]. Pocket-sized increases in plasma osmolality, sensed by osmoreceptors located primarily in the brain, trigger a release of the hormone arginine vasopressin (AVP) from the pituitary gland. The increase in plasma AVP increases h2o reabsorption in the kidney, reducing the volume of water lost via urine, increasing urine concentration, and protecting plasma osmolality. Thus, the measurement of plasma osmolality represents the issue (i.e., the successful maintenance of total body h2o and plasma osmolality), merely non the process (i.e., antidiuresis via the urine concentrating mechanism) involved in maintaining trunk water balance.

It is precisely this mechanism, the continuous adjustment of urine flow to maintain plasma osmolality, which allows biomarkers of urine concentration to be responsive to differences in fluid intake volume [14–eighteen]. Urinary output and, more specifically, urine concentration are the end consequence reflecting the antidiuretic activeness required to maintain water residual in response to varying levels of water intake and loss. Armstrong and colleagues debate that 24 hour urine osmolality (U_Osm) is an excellent indicator of 24 h hydration considering it "represents the sum of all behavioral and neuroendocrine responses which influence renal concentration or dilution throughout a twenty-four hour period" (article under review). It can therefore be argued that 24 h U_Osm is the biomarker most suitable to determine appropriate fluid intake for the individual, because information technology reflects the net sum of water gains, losses, and neuroendocrine regulatory responses. This urinary variable integrates differences in torso size, physical activity, and dietary solute load that are hard to normalize in population-based recommendations. Thus, it seems plausible that a desirable 24 h U_Osm threshold may be established. The aim of this analysis was to derive a 24 h U_Osm threshold that represents "optimal hydration"—that is, a daily fluid intake sufficient to compensate all losses and maintain a urinary output which may assistance to reduce the risk of chronic affliction.

ii. Methods

2.1. Participants and Procedure

The study was approved by the appropriate ethics commission (Comité de Protection des Personnes CPP XI in Saint-Germain-en-Laye, France) and all participants provided written informed consent. Ninety-five healthy, community-dwelling French adults (historic period: 31.five ± 4.3 years, BMI: 23.2 ± 2.vii kg·m^−two, 52% females) collected 24 h urine samples, provided fasting (morning) blood samples, and completed food and fluid intake diaries over 3 sequent weekdays. Participants collected 3 sequent 24 hour urine samples, which were checked for abyss [xiv]. Urine samples were weighed on a precision scale, osmolality was analyzed using the freezing point depression method (Messtechnik, Inc.), and specific gravity (U_sg) was measured using a hand-held digital refractometer (PEN-Urine SG, ATAGO Inc.). Urine volume (U_Vol) was calculated to the nearest mL from urine mass and U_sg. Plasma AVP (P_AVP) concentration was assessed from morning blood samples. All food and fluid consumption was recorded using a custom online food and fluid e-diary (Neometis-24WQ-Waters; MXS, French republic). Details of the study protocol, food and fluid records, urine collections, and biochemical analyses have been described elsewhere [14].

2.2. Analytical Approach

To date, the adequacy of water intake has been evaluated relative to dietary guidelines, or disease risk, or biomarkers of hydration. This analysis attempted to reconcile these 3 approaches into a combined, quantitative biomarker representing adequate intake for optimal hydration. To determine a threshold for 24 h U_Osm representing adequate intake, three strategies were used. U_Osm was assessed relative to dietary reference values, disease risk, and neuroendocrine control of water remainder to determine whether these 3 approaches converged about a mutual, biologically-significant 24 h U_Osm threshold. Specifically, urine osmolality was examined in relation to (1) existing European water intake dietary reference values [i]; (2) contempo publications linking fluid intake and urine volume to lithiasis [4] and chronic kidney disease [7]; and (3) P_AVP concentration. Statistical methods varied as a function of each approach, and included the apply of ANOVA and receiver-operating feature (ROC) analysis to decide optimal U_Osm cutting-offs. For each strategy, the statistical methodology is presented in more than detail. Moreover, due to the unique analytical approach of this study, in which three strategies are evaluated sequentially in guild to get in at a common conclusion, a cursory discussion relevant to each strategy will exist presented straight after each analysis. A general conclusion will follow.

3. Results

3.1. Fluid Intake and Urine Output

The mean ± SD (10th percentile to 90th percentile) for fluid intake and urine output were total daily fluid intake (TFI) 1.six ± 0.9 L·d⁻¹ (0.48 to 3.0  L·d⁻¹); 24 h U_Vol, 1.five ± 0.8 L (0.half dozen to 2.5 50); 24 h U_Osm, 609 ± 274 mOsm·kg⁻ⁱ (277 to 999 mOsm·kg⁻¹). At that place were moderate to stiff correlations between each pair of variables (Figure 1).

3.ii. Strategy 1: Determine the Optimal 24 h U_Osm Value to Distinguish Daily Fluid Intake Volume that Satisfies the Dietary Reference Intake for H2o

European Food Safety Authority (EFSA) acceptable intake for total water assumes that, on average, 70–80% of TWI is obtained through fluid consumption. Thus, the reference values for TFI can be approximated equally 2.0 and 1.6 L·d⁻¹ for adult men and women, respectively. In order to decide the 24 h U_Osm cut-off that would best discriminate betwixt subjects who met or exceeded and those who did not encounter the EFSA reference values for fluid intake, a binary variable was constructed based on participants' 24 h TFI (Yeah: meets or exceeds the sex-specific reference value for intake; No: does not meet reference value). Logistic regression of 24 h U_Osm confronting this binary effect was performed, and a ROC analysis was used to determine the optimal U_Osm cutoff value. No aligning was made to favor either sensitivity or specificity. The optimal 24 h U_Osm for distinguishing between those who met or exceeded and those who did not run into EFSA TFI reference values was 544 mOsm·kg⁻¹ (area under the curve = 0.895; Figure 2).

In establishing daily reference values for TWI, the EFSA panel relied in part on a calculation of the theoretical amount of urine required to excrete 24 h solute at a "desirable urine osmolarity" of 500 mOsm·L⁻¹ [1]. The cutting-off determined using the ROC analysis (544 mOsm·kg⁻¹) is consistent with this EFSA calculation. The similarity between the experimentally-derived cutoff in this sample and the EFSA theoretical calculation is remarkable, considering that the EFSA calculations relied on average dietary solute ingestion from diverse European dietary population surveys. In our sample, 24-hr urine from European participants in normal daily living weather condition, consuming their normal daily nutrient and fluids, provides experimental support for a 24 h U_Osm threshold approaching 500 mOsm·kg⁻¹ as a way to evaluate whether full fluid intake meets European reference values.

3.3. Strategy 2: Consider 24 h U_Osm and Relative Gamble for Disorders of the Kidneys and Urinary Tract

3.3.1. Urolithiasis

The relationship betwixt fluid intake, urine book, and kidney stones has been widely reported [11, 19–22]; still, few studies take evaluated the risk of stone formation relative to specific volumes of fluid intake or urine output. In a prospective test of data from the Nurses' Health Study (NHS), Curhan et al. [4] determined that the multivariate-adjusted odds-ratio (OR) for kidney stones was lower when TFI exceeded 1850 mL·d^−ane in a sample of young women. Using the female person participants in our sample ( women providing 147 fluid records and corresponding 24 h urine collections), logistic regression and ROC analysis with a binary outcome of FI greater than or less than 1850 mL·d⁻¹ showed the optimal 24 h U_Osm cutoff for distinguishing those who met the fluid intake threshold for reduction in stone run a risk to exist 525 mOsm·kg⁻¹ (AUC = 0.92; sensitivity 0.95; specificity 0.77). This provides a second, independent support for a 24 h 60 minutes U_Osm threshold budgeted 500 mOsm·kg^−ane as an indicator of adequate total fluid intake.

A threshold of 500 mOsm·kg⁻¹ is also supported past data from the only prospective, randomized controlled trial of increased water intake to prevent stone recurrence [23]. Borghi et al. reported that in a population of stone-formers, increasing 24 h U_Vol above 2 L·d⁻¹ (U_Vol, 2.i–ii.vi L) resulted in a 50% lower stone recurrence rate over v years. In our written report sample, 79% of urine collections were accurately classified as being higher up or below two L·d⁻ⁱ based upon a U_Osm cutoff of 500 mOsm·kg^−one (98% sensitivity, 74% specificity). Moreover, the optimal cut point for distinguishing 24 h U_Vol to a higher place or below 2 L·d⁻¹ likewise approached 500 mOsm·kg⁻¹ (448 mOsm·kg⁻¹; 98% sensitivity, 82% specificity).

This analysis of 24 h U_Osm relative to rock disease take a chance, performed independently of the assay relative to EFSA intake guidelines, is especially interesting because that both methods converge on approximately 500 mOsm·kg⁻ⁱ as a desirable 24 h U_Osm (Table i). The communication to stone-formers to increase their urine volume is common in clinical practice, and several studies have confirmed the importance of loftier fluid intake and urine output on secondary stone prevention. The underlying principle of these recommendations is to dilute urinary solute concentration and prevent supersaturation and crystallization. While not sufficient on its own, urine dilution is a key component in the therapeutic strategy for preventing recurrence in renal stone formers. Since the goal is to prevent supersaturation by diluting urine, at that place is a rationale for taking into account full urine osmolyte content and concentration. Targeting a 500 mOsm·kg⁻¹ urine osmolality threshold rather than a "universal" optimal urine volume (2 L/day is a mutual recommendation) represents an advantage: it takes into account individual metabolic constraints and provides a uncomplicated style to assess by simply checking urine color or specific gravity. In this sense, a 24 h U_Osm target outperforms both h2o intake and urine book-based recommendations, as it is the only measure capable of accounting for differences in intake, loss, and dietary solute load, which will influence the minimum water requirement. Thus, establishing a U_Osm target of ≤500 mOsm·kg⁻¹ as a physiological index of hydration appears relevant both for tracking adequate intake in the general population, likewise as for specific patient groups such every bit stone formers.

Reference	Description	Criterion value	UOsm cutoff value derived from ROC analyses	Sensitivity	Specificity
EFSA [1]	Dietary reference value for full fluid intake (estimated to exist 80% of total h2o intake)	TFI ≥ 2.0 L·d−i (men) or ≥ 1.6 L·d−1 (women)	544 mOsm·kg−1	0.86	0.80
Curhan et al. [4]	Multivariate-adjusted odds-ratio (OR) for kidney stones in women with college TFI	TFI ≥ 1850 mL·d−one	525 mOsm·kg−1	0.95	0.77
Borghi et al. [23]	In recurrent stone formers, increasing 24 h UVol resulted in a fifty% lower stone recurrence rate over 5 years	24 h UVol ≥ ii.0 L·d−i	448 mOsm·kg−i	0.98	0.82

three.three.2. Chronic Kidney Illness

Recent studies have reported that depression 24 h urine volume and depression daily fluid intake are associated with a higher risk of chronic kidney disease [7, 9]. Clark and colleagues assessed the rate of annual eGFR decline in 2148 adults over 7 years and found an changed, graded, dose-response human relationship between 24 h U_Vol and annual renal turn down. Balmy to moderate renal decline was slowest in people with the highest U_Vol (≥3 L·d⁻¹: multivariate-adjusted OR [95% CI]: 0.66 [0.46–0.94]; ii.0–ii.9 L·d^−ane: OR 0.84 [0.67–1.05]) and fastest in those with everyman U_Vol (<1 L·d⁻¹: OR i.33 [1.01–1.75]), compared to the reference urine volume. Using the dataset described above and the 4 U_Vol categories described past Clark et al., ANOVA revealed that 24 h U_Osm was significantly different between categories of U_Vol (F 3,281 = 148; ). Hateful [95% CI] 24 h U_Osm was 872 837,906; 564 533,594; 312 265,359; and 290 200,380 mOsm·kg⁻ⁱ in the respective urine volume categories (<1.0; 1.0–1.9; 2.0–2.9; ≥3.0 Fifty/day). Figure 3 illustrates that when 24 h urine book was less than ane L·d⁻ⁱ, corresponding to Clark's highest category of relative risk, 96% of U_Osm values were >500 mOsm·kg⁻¹. In dissimilarity, when 24 h urine volume was ≥2 L·d⁻¹L, 100% of U_Osm values were ≤500 mOsm·kg⁻¹.

(a)

(b)

Clear-cut thresholds for biological variables rarely exist, and individual differences in water metabolism are no exception. The two independent approaches described above, using intake reference values and disease gamble, practice not result in identical U_Osm cutoffs. Yet, the fact that all approaches converged effectually approximately 500 mOsm·kg^−ane is quite remarkable. The optimal U_Osm cutoff to determine which adults met or exceeded intake guidelines [1, 2] was 544 mOsm·kg⁻¹; the cutoff for women who met the fluid intake volume for kidney stone risk reduction [4] was 525 mOsm·kg⁻¹; and the cutoff for adults who increased their urine volume for secondary stone prevention [23] was 448 mOsm·kg⁻¹. Moreover, the urine book associated with adventure reduction for chronic kidney disease farther supports a desirable 24 h U_Osm of less than 500 mOsm·kg⁻¹. Thus, it appears that a 24 h U_Osm threshold of ≤ 500 mOsm·kg⁻¹ is suggestive of a daily fluid intake that is acceptable to (a) satisfy European intake reference values and (b) play a function in the prevention of pathologies of the kidneys and urinary tract.

3.iv. Strategy three: Assess P_AVP Concentration in Relation to U_Osm

AVP is the major actor in a cascade of hormones that regulate the permeability and absorption of h2o in the kidneys, maintaining total body h2o homeostasis across a wide range of fluid intake volumes. P_AVP concentration is thus a straight reflection of antidiuretic effort to preserve full torso water in response to insufficient intake or increased water loss. Of the 285 records of daily fluid intake and urine osmolality, 283 had associated P_AVP measures. Mean P_AVP concentration was compared across 3 U_Osm categories: ≤500 mOsm·kg⁻¹, corresponding to the threshold for intake adequacy proposed in this paper; >800 mOsm·kg⁻¹, respective to an indication of mild dehydration [24]; and 501–800 mOsm·kg⁻ⁱ. ANOVA revealed significant differences in P_AVP between the three U_Osm categories [F (2,720) = 34.01; ]. P_AVP concentration beyond each ascending category of U_Osm was (mean [95% CI]) 1.76 [1.59,ane.93]; 2.39 [two.11,2.67]; and iii.two [2.86,3.54] pg·mL⁻¹, respectively, representing a mean increase of 0.6 to 0.8 pg·mL⁻¹ between U_Osm categories.

While comparative data are limited, the mean P_AVP when U_Osm ≤ 500 mOsm·kg⁻¹ was very like to baseline AVP concentrations reported in previous studies (Effigy 4). The hateful AVP concentration when U_Osm was between 501 and 800 mOsm·kg^−ane was similar to P_AVP previously reported in female subjects afterwards 12 hours of fluid deprivation [25], and the mean P_AVP when U_Osm was greater than 800 mOsm·kg⁻ⁱ was similar to values previously reported during 24 hours of fluid deprivation [26]. This reveals that the antidiuretic efforts of the kidney are increased even when 24 h urine osmolality is below 800 mOsm·kg⁻¹ and suggests that even moderately high U_Osm (501–800 mOsm·kg^−ane) is indicative of increased antidiuretic effort to maintain full body water.

Osmotic stimulation of AVP is quite sensitive, and changes of less than 1% in plasma osmolality are capable of triggering the release of AVP. It has been reported that an increase of 1 mOsm·kg⁻ⁱ in plasma produces a change of between 0.4 and 0.viii pg·mL⁻ⁱ in circulating AVP [27]. Similarly, the renal response to increased circulating AVP is as sensitive, with maximal urine concentration occurring when plasma AVP concentration approaches 4 to v pg·mL⁻¹. While the differences in plasma AVP observed between U_Osm thresholds are quantitatively small, they are clinically significant in terms of their impact on the renal urine concentrating mechanism: small, initial increases from baseline levels of plasma AVP have a much greater relative effect to decrease urine period than do further increases budgeted 5 pg·mL^−ane [27]. Thus, even without a significant reduction in total torso h2o, insufficient fluid intake appears to mimic the hormonal contour and urine concentration seen in fluid restriction and dehydration.

iv. Discussion

Daily water needs are highly private due to differences including trunk size, climate and environment, daily activities, metabolism, and dietary solute load. Withal, given that h2o intake recommendations are constructed to satisfy the general needs of a population, it is difficult for individuals to considerately assess whether they are drinking enough to meet their specific needs. The nowadays study aimed to determine a 24 hour U_Osm alphabetize which would reverberate an acceptable daily fluid intake for optimal hydration, using three approaches: (1) comparisons with intake recommendations from EFSA [1]; (two) associations between intake, urinary output, and diseases of the kidneys and urinary tract; and (3) associations between U_Osm and AVP. Together, the first and 2nd approaches propose that a 24 60 minutes U_Osm of less than or equal to 500 mOsm·kg⁻¹ (which will be referred to, for simplicity, equally U500) represents an intake that is adequate to compensate for daily losses and ensure a urinary output sufficient to reduce the risk of urolithiasis and pass up in renal role. Moreover, U500 was supported by the third approach, which revealed that 24 h urine osmolality of >500 mOsm·kg⁻¹ was associated with elevated plasma AVP concentrations suggestive of antidiuretic effort.

Previous work to establish a U_Osm threshold has focused on the detection of dehydration, rather than on the adequacy of intake for health. A 24-hour U_Osm threshold of approximately 800 mOsm·kg^−one to find dehydration has been supported both in children and adults. Manz and Wentz [28] defined 830 mOsm·kg^−one every bit the lower jump for hypohydration in children, based on a calculation of the mean maximal urine concentrating chapters, minus 2 standard deviations, thereby covering the "minimum maximal urine concentrating chapters" of 98% of the population described (i.e., European children and adolescents consuming a poly peptide-rich western nutrition). A nearly identical criterion value for balmy dehydration (831 mOsm·kg⁻¹; 91% sensitivity, 91% specificity) was reported in a sample of adults [13]. For acute dehydration, a threshold of ~800 mOsm·kg⁻ⁱ appears to be reasonable. However, drinking just enough to maintain a 24 h U_Osm below 800 mOsm·kg⁻¹ may non be sufficient to ensure optimal hydration, if i considers not only dehydration only also the chance for health touch on. Growing evidence suggests that a truly adequate intake requires drinking more than strictly physiologically necessary.

The body's ability to preserve plasma osmolality and total torso water despite differences in water intake is due to the sensitive regulation of urine concentration past the kidneys, largely modulated through the release of the antidiuretic hormone, AVP. Although low water intake tin can be compensated by loftier antidiuretic activity and a low urine output, the risk for some chronic diseases appears to be associated with low water intake [8–x, twenty]; low-volume, highly-concentrated urine output [seven, 22, 23]; and expression of the hormone AVP [29–31]. Acting upon V2 receptors expressed in the kidney, AVP appears to contribute to the progression of chronic kidney affliction and refuse in glomerular filtration rate [29, thirty] and may be involved in the progression of autosomal ascendant polycystic kidney disease (ADPKD) [32]. Moreover, this hormone is also associated with vascular function [31] and regulation of blood glucose [10, 33]. The activity of AVP on V1 receptors, expressed in vascular smooth muscle cells and mediating vasoconstriction, as well suggests that AVP may exist involved in the regulation of claret pressure and that its chronic hyperexpression may be linked to hypertension, though more than work is needed to empathize its long-term effects. An observational written report of normotensive and hypertensive patients [31] revealed higher plasma AVP in hypertensive subjects than in normotensive subjects and besides demonstrated a linear relationship between AVP, systolic, and diastolic blood pressure. Notably, the AVP concentration reported in hypertensive subjects is consistent with the AVP concentration measured in subjects with U_Osm > 500 mOsm·kg⁻¹.

There is insufficient prove to define a range for "salubrious" plasma AVP concentration. However, indirect evidence for the benefits of lowering plasma AVP can be seen in treatment advances in ADPKD. Tolvaptan, an AVP-V2 receptor inhibitor, has been demonstrated to be effective in slowing the rate of cyst growth and kidney function turn down [34]. A logical adjacent step that must be evaluated is whether reducing plasma AVP via increased water intake, instead of via pharmacological blockade, is every bit effective. While preliminary evidence in rats suggests that water intake is indeed constructive in slowing the progression of the disease [34], a threshold for a "good for you" plasma AVP concentration remains to exist established.

There are limitations to the analytical approach presented in a higher place. The associations between fluid intake, U_Osm, chronic disease, and AVP are derived mostly from cross-sectional and accomplice studies. Prospective, randomized controlled studies and farther piece of work to confirm or refine this index are sorely needed. However, the strength of the present analysis is that several approaches independently betoken towards a like value of U500 as an index representative of adequate intake. A major reward is that the method can be applied to a variety of populations and situations. Urine osmolality reflects the net sum of all fluid-electrolyte regulation; therefore, information technology intrinsically takes into account differences in diet-related osmotic load, total daily h2o consumption, climate, body size, sweat loss and water gained via metabolism in those who practice strenuously. Thus, for the private, U500 may reverberate a daily water intake that is sufficient not only to encounter the physiological water requirement, but likewise to ensure adequate urinary excretion and downregulate AVP secretion, both of which may reduce the risk of chronic renal and metabolic disease.

5. Conclusion

Excreting a low volume of concentrated urine appears to have costs that are both straight (i.e., faster decline in GFR and incidence of kidney stone recurrence) and indirect (i.e., association betwixt increased circulating AVP and glycemic command, diabetes, hypertension, and ADPKD). Thus, maintaining dilute urine may have some benefits; however, today, the precise dose-response relationship between h2o intake, U_Osm, and disease risk is not sufficiently clear. Growing evidence suggests that a daily fluid intake higher up that which is physiologically necessary for water residual is desirable. Maintaining a sufficiently low 24 h U_Osm (i.e., via increased full daily fluid intake) reduces the antidiuretic endeavor of the kidneys and is therefore an easy and cost-effective style to reduce the negative effects observed in association with increased AVP concentration. Maintaining a 24 h U_Osm below 500 mOsm·kg⁻¹ may thus be considered every bit a elementary index of optimal hydration.

Conflict of Interests

Erica T. Perrier, Inmaculada Buendia-Jimenez, Mariacristina Vecchio, and Alexis Klein are employees of Danone Research, France. Lawrence E. Armstrong and Ivan Tack are occasional consultants for Danone Enquiry but did not receive any compensation related to this study. All authors have read and approved the final paper.

Copyright

Copyright © 2015 Erica T. Perrier et al. This is an open access commodity distributed under the Artistic Commons Attribution License, which permits unrestricted apply, distribution, and reproduction in whatsoever medium, provided the original work is properly cited.

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Source: https://www.hindawi.com/journals/dm/2015/231063/

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