High Water Intake Research Articles

Psychosis-related polydipsia and chronic hyponatremia – A case report

IntroductionPsychogenic polydipsia has an estimated prevalence of 6–20% in psychiatric population. Although first described in the 1930s, there are few studies addressing this problem and its management. The high water intake can lead to severe hyponatremia with a mortality rate high enough to merit clinical concern.AimsReport a case of a schizophrenic patient with psychogenic polydipsia and hyponatremia.MethodsRetrospective review of the clinical file and literature research on this topic.ResultsA 41-year-old man with a long-term schizophrenia presented to the emergency room (ER) with exacerbation of psychotic symptoms. In the prior 24 months, he had stopped medication and began excessive water intake (5 to 10 L/day). He presented with auditory hallucinations, passivity phenomena and persecutory and other delusional thoughts that justified this behavior – “The water will end; I have to stock it, like camels do”. Presently he had an asymptomatic hyponatremia (128 mg/dL), but 6 months before he had been admitted in the ER with vomiting, altered state of consciousness and convulsions secondary to severe hyponatremia (108 mg/dL). During the present hospitalization, organic causes of hyponatremia were excluded and he was started on behavioral measures and antipsychotics. The psychotic symptoms improved and there was no need for water restriction after the first week, with restored natremia values on discharge.ConclusionsWith this case report we intended to raise awareness on this potentially fatal condition that despite its prevalence has no defined diagnostic criteria, nor established controlled trials concerning the effectiveness of treatments.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Water intake and beverage consumption of pre-schoolers from six European countries and associations with socio-economic status: the ToyBox-study.

To study the quantity and quality of water intake from beverages among pre-schoolers and investigate associations with gender and socio-economic status (SES). Kindergarten-based cross-sectional survey within the large-scale European ToyBox-study. A standardized protocol was used and parents/caregivers filled in sociodemographic data and a semi-quantitative FFQ. Kindergartens in six European countries (Belgium, Bulgaria, Germany, Greece, Poland and Spain). European pre-schoolers (aged 3·5-5·5 years) and their parents/caregivers (n 7051). Mean water intake was 1051 ml/d; plain water, 547 ml/d; plain milk, 241 ml/d; other fruit juice, 104 ml/d; pure fruit juice, 59 ml/d; soft drinks, 55 ml/d; tea, 45 ml/d; sugared and chocolate milk, 37 ml/d; smoothies, 15 ml/d; and light soft drinks, 6 ml/d. Boys had a higher water intake than girls due to a higher consumption of plain water, but more importantly to the consumption of beverages of less quality. Lower-SES pre-schoolers scored better on quantity than high-SES pre-schoolers, but as a consequence of consumption of sugared beverages. Nevertheless, the associations differed by country. The water intake from beverages did not meet the European Food Safety Authority standard of 1280 ml/d; especially in Western European countries water intake from beverages was low. The most important water sources were plain water, milk and fruit juices. Interventions aiming at a proper and sufficient water intake should focus on both quantity and quality. Messages about water and water sources should be clear for everyone and interventions should be sufficiently tailored.

Evaluation of Polyuria: The Roles of Solute Loading and Water Diuresis

Polyuria, defined as daily urine output in excess of 3.0 to 3.5L/d, can occur due to solute or water diuresis. Solute-induced polyuria can be seen in hospitalized patients after a high solute load from exogenous protein administration or following relief of urinary obstruction. Similar clinical scenarios are rarely encountered in the outpatient setting. We describe a case of polyuria due to high solute ingestion and excessive water intake leading to a mixed picture of solute and water diuresis. Restriction of the daily solute load and water intake resulted in complete resolution of polyuria. Determination of the daily excreted urinary osmoles may yield important clues to the cause of polyuria and should be included in the routine workup of polyuria.

Digestive parameters and energy assimilation of Cape porcupine on economically important crops

To better understand how Cape porcupines are able to successfully occupy many agricultural lands, we studied their digestive parameters and energy assimilation when fed three economically important agricultural crops (potatoes [Solanum tuberosum], sweet potatoes [Ipomoea batatas] and butternut [Juglans cinerea]). Daily food intake, daily gross energy intake, daily faecal energy loss, daily energy assimilated, daily water intake and apparent assimilation efficiency were calculated for each porcupine and for each diet trial. Cape porcupines maintained body mass on all three experimental diets and energy intake ranged from 3 002.36 kJ kg−1 d−1 (potato) to 4 499.00 kJ kg−1 d−1 (sweet potato). The moisture content in each experimental diet was relatively high (>60%) and preformed water intake of winter acclimated Cape porcupines ranged from 60 ml kg−1 d−1 (potato) to 100 ml kg−1 d−1 (sweet potato). Assimilation efficiencies were high (>85%) on all three diets. Cape porcupines ingested c. 1.5–2.7 kg of each crop daily, translating to potentially large economic impacts on farmers. Knowledge and understanding of Cape porcupine food intake and dietary requirements give insight to their potential impact on commercial crops. This may aid in developing management and conservation strategies needed to manage this human–wildlife conflict.

A Water and Education Provision Intervention Modifies the Diet in Overweight Mexican Women in a Randomized Controlled Trial1–3

There is minimal information on the impact of replacing sugar-sweetened beverage (SSB) consumption with water on diet quality from randomized controlled trials. We evaluated the effect of a water intake intervention on diet quality in overweight Mexican women. Women with a body mass index ≥25 and <39, 18-45 y old, and a self-reported high intake of SSBs (≥250 kcal/d) were randomly allocated to either the water and education provision (WEP) group (n = 120) or the education provision (EP) only group (n = 120). Each group received monthly nutrition counseling, and the WEP group received biweekly water deliveries for 9 mo. Three 24-h recalls, anthropometry, and demographic information were collected at baseline, and 3, 6, and 9 mo. Energy, macronutrient, sugar, SSB, fruit and vegetable, salty snack, cake and cookie, and fast food intakes were assessed in study completers (n = 189) classified by intervention assignment and by actual water intake at every time point (low <1200 vs. high ≥1200 mL/d). The WEP group reported greater decreases in SSB intake than the EP group (from 20.9% to 10.3% of energy/d vs. from 20.1% to 17.8%). Thirty-eight percent of the EP group and 84.3% of the WEP group reported attaining a water intake ≥1200 mL/d. Reductions in energy intake and food groups were similar across intervention groups. However, the high actual water intake group reported greater increases vs. the lower intake group in intake of fruits and vegetables (117 vs. 47 g/d), as well as larger reductions in salty snacks (4.6 vs. 0.7 g/d) and cakes and cookies (31.7 vs. 14.7 g/d). Other than SSBs, improvements in food group intake did not differ by intervention group in overweight Mexican women. However, post hoc analyses suggested that achieving a high actual water intake was associated with additional beneficial changes in food group intake. This trial was registered at clinicaltrials.gov as NCT01245010.

Is surgery necessary for 'mild' or 'asymptomatic' hyperparathyroidism?

A large majority of the currently diagnosed patients with hyperparathyroidism (PHPT) are mild or asymptomatic, mainly women after menopause. Following the debate held at the 16th European Congress of Endocrinology in Wroclaw (Poland) from May 3-7, 2014, arguments are here presented by a surgeon and a medical practitioner considering these situations rather have to profit from surgery, or simply from survey. For the trained endocrine surgeon, it is evident that parathyroidectomy confirms the diagnosis and undoubtedly reduces the discomfort felt by certain patients, prevents all risks of complications, removes patients and medical teams from the monitoring and represents a real individual financial benefit. On the other hand, the medical practitioner considers that mild or asymptomatic PHPT is commonly stable, and very rare are the subjects at risk of complications, particularly of fractures; prevention of vascular and metabolic disorders, nephrolithiasis and bone rarefaction justify regular physical exercise, a safe alimentation, a sufficient calcium and high water intake, the correction of the frequent deficit in vitamin D; finally has also to be considered the impossibility to refer to specialized (endocrine) surgeons, the enormous cohort of subjects more than 50 years with 'mild' or 'asymptomatic' PHPT. The surgeon and the medical practitioner agree to consider that in patients with 'mild' or 'asymptomatic' disease, there is no place for medical treatments, in particular calcimimetics and bisphophonates. Both agree that further studies are needed to clarify the long-term prognosis of operated and non-operated PHPT in term of fractures, cardiovascular risk and mortality. Individual and collective cost/benefit ratios of surgery or survey are also still imperfectly evaluated.

Nephron-specific deletion of the prorenin receptor causes a urine concentration defect.

The prorenin receptor (PRR), a recently discovered component of the renin-angiotensin system, is expressed in the nephron in general and the collecting duct in particular. However, the physiological significance of nephron PRR remains unclear, partly due to developmental abnormalities associated with global or renal-specific PRR gene knockout (KO). Therefore, we developed mice with inducible nephron-wide PRR deletion using Pax8-reverse tetracycline transactivator and LC-1 transgenes and loxP flanked PRR alleles such that ablation of PRR occurs in adulthood, after induction with doxycycline. Nephron-specific PRR KO mice have normal survival to ∼1 yr of age and no renal histological defects. Compared with control mice, PRR KO mice had 65% lower medullary PRR mRNA and protein levels and markedly diminished renal PRR immunofluorescence. During both normal water intake and mild water restriction, PRR KO mice had significantly lower urine osmolality, higher water intake, and higher urine volume compared with control mice. No differences were seen in urine vasopressin excretion, urine Na(+) and K(+) excretion, plasma Na(+), or plasma osmolality between the two groups. However, PRR KO mice had reduced medullary aquaporin-2 levels and arginine vasopressin-stimulated cAMP accumulation in the isolated renal medulla compared with control mice. Taken together, these results suggest nephron PRR can potentially modulate renal water excretion.

NEPHRON SPECIFIC DELETION OF PRORENIN RECEPTOR MODULATES WATER AND SODIUM HOMEOSTASIS

The prorenin receptor (PRR), a newly discovered component of the RAS, has been localized to the collecting duct, distal convoluted tubule, proximal tubule and podocytes. Targeted deletion of PRR, whether global or cell-specific, has resulted in either early lethality or organ malformation due to abnormal lysosomal acidification. Consequently, the physiological significance of nephron derived PRR is unclear. To examine this, we developed mice with inducible nephron-wide PRR deletion. Mice were generated which were hemizygous for the Pax8-rtTA and LC-1 transgenes and homozygous for loxP flanked PRR alleles to achieve nephron-specific PRR disruption after doxycycline induction. Adult Pax8-rtTA/LC-1/floxed PRR mice were treated with doxycycline 2 mg/ml in drinking water for 12 days and studied 4 weeks after treatment. Nephron specific PRR KO mice have normal survival and no histological defects in the kidney. Compared to controls, PRR knockout (KO) mice demonstrated 60% lower PRR mRNA levels and significantly lower PRR immunofluorescence. Under both Na intake, PRR KO mice had significantly lower urine osmolality, higher water intake and higher urine volume compared to controls. No notable differences were seen in body weight or food intake. PRR KO mice had higher Na excretion compared to controls on days 1 and 2 of change from normal to low Na diet but similar Na excretion on other days of low Na intake. Finally, no detectable differences in BP were noted between the two groups on normal or low Na diet (7 days each). These data suggest that nephron PRR can potentially modulate water and sodium homeostasis. * P < 0.05 Normal Na diet (0.25%) lLow Na diet (0.03%) Controls PRR KO Controls PRR KO Body weight (g) 26.9 ± 3.1 24.2 ± 1.6 26.3 ± 2.7 23.3 ± 1.4 Food intake (g) 5.2 ± 0.3 4.4 ± 0.3 4.0 ± 0.3 3.8 ± 0.3 Water intake (ml) 3.9 ± 0.6 8.9 ± 1.3* 3.9 ± 0.4 7.2 ± 0.8* Urine Volume (ml/day) 1.7 ± 0.2 6.0 ± 1.0* 1.3 ± 0.4 4.4 ± 0.7* Urine osmolality (mosm Kg/H2O) 3133 ± 396 1325 ± 426* 1679 ± 270 976 ± 320* Urine NaV (μmol/d) 222 ± 28 236 ± 32 42 ± 6 66 ± 10* Urine KV(μmol/d) 311 ± 32 298 ± 28 184 ± 31 236 ± 20 Systolic blood pressure (mm Hg) 119 ± 3 122 ± 4 118 ± 4 122 ± 2 Diastolic blood pressure (mm Hg) 94 ± 3 96 ± 3 93 ± 2 95 ± 3

Initial conditioning of polymer eelectrolyte membrane fuel cell by temperature and potential cycling.

Polymer electrolyte membrane fuel cells need initial conditioning, activation or break-in the first time they are operated after being assembled. During this period performance of the fuel cell improves until it reaches its nominal performance. The exact mechanism of this initial conditioning is not completely understood, but it is assumed that during the conditioning process the polymer membrane, as well as the polymer in the catalyst layer, get humidified, and the number of active catalyst sites increases. Activation procedure proposed here consists of temperature and potential cycling. Temperature cycling is a new approach for the conditioning and the idea is to rapidly cool the running cell at some point to allow the membrane to equilibrate with condensed water which should result in higher intake of water within the membrane. The results show that proposed procedure is better or at least comparable to some conventional procedures for the initial conditioning.

Evaluating Hyponatremia in Non-Diabetic Uremic Patients on Peritoneal Dialysis.

♦ An approach to hyponatremia in uremic patients on peritoneal dialysis (PD) necessitates the assessment of intracellular fluid volume (ICV) and extracellular volume (ECV). The aim of the study was to evaluate the association of plasma sodium (Na(+)) concentration and body fluid composition and identify the causes of hyponatremia in non-diabetic PD patients. ♦ Sixty non-diabetic uremic patients on PD were enrolled. Baseline body fluid composition, biochemistry, hand-grip test, peritoneal membrane characteristics, dialysis adequacy, Na(+) and water balance, and residual renal function (RRF) were measured. These parameters were reevaluated for those who developed hyponatremia, defined as serum Na(+) concentration < 132 mmol/L and a decline in serum Na(+) > 7 mmol/L, during monthly visits for 1 year. Body fluid composition was determined by multi-frequency bioelectrical impedance (BIA). ♦ There was no significant correlation between serum Na(+) concentrations and any other parameters except a negative correction with overnight ultrafiltration (UF) amount (p = 0.02). The ICV/ECV ratio was positively correlated with serum albumin (p < 0.005) and hand grip strength (p < 0.05). Over 1 year, 9 patients (M:F = 3:6, aged 35 - 77) with 4 different etiologies of hyponatremia were identified. Hyponatremic patients with a body weight (BW) loss had either an increased ICV/ECV ratio associated with primarily a negative Na(+) balance (n = 2) or a reduced ratio of ICV/ECV associated with malnutrition (n = 2). In contrast, hyponatremic patients with a BW gain had either a reduced ICV/ECV ratio associated with a rapid loss of RRF and a higher peritoneal permeability (n = 2) or a normal to increased ICV/ECV ratio associated with high water intake (n = 3). ♦ Besides BW change and ultrafiltration rate, the assessment of ICV/ECV ratio is valuable in identifying the etiologies of hyponatremia in PD and provides a guide for optimal therapy.

Thiazide-induced hyponatraemia is associated with increased water intake and impaired urea-mediated water excretion at low plasma antidiuretic hormone and urine aquaporin-2

Hyponatraemia is a common, potentially life-threatening, complication of thiazide diuretics. The mechanism of thiazide-induced hyponatraemia is incompletely understood. Previous experiments have suggested a direct effect of thiazide diuretics on the plasma membrane expression of aquaporin (AQP)2. We examined the effects of a single re-exposure to hydrochlorothiazide (HCTZ) 50 mg on water balance, renal sodium handling and osmoregulation in 15 elderly hypertensive patients with a history of thiazide-induced hyponatraemia and 15 matched hypertensive controls using thiazide diuretics without previous hyponatraemia. Patients with thiazide-induced hyponatraemia had significantly lower body weight and lower plasma sodium and osmolality at baseline. After HCTZ administration, plasma sodium and osmolality significantly decreased and remained lower in patients compared with controls (P < 0.001). Plasma antidiuretic hormone (ADH) and urine AQP2 were low or suppressed in patients, whereas solute and electrolyte-free water clearance was significantly increased compared with controls. Ad libitum water intake was significantly higher in patients (2543 ± 925 ml) than in controls (1828 ± 624 ml, P < 0.05), whereas urinary sodium excretion did not differ. In contrast, urea excretion remained significantly lower in patients (263 ± 69 mmol per 24 h) compared with controls (333 ± 97 mmol per 24 h, P < 0.05) and predicted the decrease in plasma sodium following HCTZ administration. Thiazide diuretics are associated with markedly impaired free water excretion at low ADH and AQP2 in elderly patients. The higher water intake and lower urea excretion in patients points to an important role for polydipsia and urea-mediated water excretion in the pathogenesis of thiazide-induced hyponatraemia.

Glycogen synthase kinase 3α regulates urine concentrating mechanism in mice.

In mammals, glycogen synthase kinase (GSK)3 comprises GSK3α and GSK3β isoforms. GSK3β has been shown to play a role in the ability of kidneys to concentrate urine by regulating vasopressin-mediated water permeability of collecting ducts, whereas the role of GSK3α has yet to be discerned. To investigate the role of GSK3α in urine concentration, we compared GSK3α knockout (GSK3αKO) mice with wild-type (WT) littermates. Under normal conditions, GSK3αKO mice had higher water intake and urine output. GSK3αKO mice also showed reduced urine osmolality and aquaporin-2 levels but higher urinary vasopressin. When water deprived, they failed to concentrate their urine to the same level as WT littermates. The addition of 1-desamino-8-d-arginine vasopressin to isolated inner medullary collecting ducts increased the cAMP response in WT mice, but this response was reduced in GSK3αKO mice, suggesting reduced responsiveness to vasopressin. Gene silencing of GSK3α in mpkCCD cells also reduced forskolin-induced aquaporin-2 expression. When treated with LiCl, an isoform nonselective inhibitor of GSK3 and known inducer of polyuria, WT mice developed significant polyuria within 6 days. However, in GSK3αKO mice, the polyuric response was markedly reduced. This study demonstrates, for the first time, that GSK3α could play a crucial role in renal urine concentration and suggest that GSK3α might be one of the initial targets of Li(+) in LiCl-induced nephrogenic diabetes insipidus.

High Water Intake and Progression of Chronic Kidney Diseases.

Impact of water intake on the courses of chronic kidney and urinary tract diseases, such as urolithiasis, urinary tract infections, chronic kidney diseases (CKD), autosomal dominant polycystic kidney diseases and bladder cancer, has recently been studied. It still remains controversial whether increased water intake slows the progression of CKD or not. However, high water intake suppresses plasma levels of arginine vasopressin (AVP), which is expected to be beneficial for the preservation of the kidney function. Previous studies suggest that water intake suppresses plasma levels of AVP, and high levels of AVP have been suggested to play deleterious roles in animal models of kidney disease. Moreover, recent epidemic of CKD of unknown origin, which was supposed to be related to the insufficient water intake and chronic volume depletion, has been reported in Central America, further suggesting that the suppression of AVP by sustained water intake might be beneficial in this CKD population. Indeed, the data from recent studies were consistent with the view that high water intake is associated with slower progression of CKD. However, contradictory findings also exist. The intriguing effects of increased urine volume in preserving the glomerular filtration rate in human patients with CKD require more large and well-designed randomized prospective clinical trials.

Effects of hydration in rats and mice with polycystic kidney disease.

Vasopressin and V2 receptor signaling promote polycystic kidney disease (PKD) progression, raising the question whether suppression of vasopressin release through enhanced hydration can delay disease advancement. Enhanced hydration by adding 5% glucose to the drinking water has proven protective in a rat model orthologous to autosomal recessive PKD. We wanted to exclude a glucose effect and explore the influence of enhanced hydration in a mouse model orthologous to autosomal dominant PKD. PCK rats were assigned to normal water intake (NWI) or high water intake (HWI) groups achieved by feeding a hydrated agar diet (HWI-agar) or by adding 5% glucose to the drinking water (HWI-glucose), with the latter group used to recapitulate previously published results. Homozygous Pkd1 R3277C (Pkd1(RC/RC)) mice were assigned to NWI and HWI-agar groups. To evaluate the effectiveness of HWI, kidney weight and histomorphometry were assessed, and urine vasopressin, renal cAMP levels, and phosphodiesterase activities were measured. HWI-agar, like HWI-glucose, reduced urine vasopressin, renal cAMP levels, and PKD severity in PCK rats but not in Pkd1(RC/RC) mice. Compared with rat kidneys, mouse kidneys had higher phosphodiesterase activity and lower cAMP levels and were less sensitive to the cystogenic effect of 1-deamino-8-d-arginine vasopressin, as previously shown for Pkd1(RC/RC) mice and confirmed here in Pkd2(WS25/-) mice. We conclude that the effect of enhanced hydration in rat and mouse models of PKD differs. More powerful suppression of V2 receptor-mediated signaling than achievable by enhanced hydration alone may be necessary to affect the development of PKD in mouse models.

Acyclovir and Hyponatremia

A 61-year-old man attended the emergency department with decreased level of consciousness, repetitive language, and memory loss. Clinical history included type II diabetes and hypertension. Domiciliary treatment included oral metformin 850 mg every 24 hours and oral indapamide 2.5 mg every 24 hours. Laboratory tests disclosed high glycemia (198 mg/dL), increased C-reactive protein (7.4 mg/dL), and normal renal function. Intravenous acyclovir of 800 mg every 8 hours was started on admission due to suspicion of viral encephalitis. Blood analysis on 10th day displayed hyponatremia (123 mmol/L) that was at first explained by the high water intake in the 3 preceding days; therefore, water restriction was decided. Nuclear magnetic resonance on day 14 identified an ictus and treatment with acyclovir was withdrawn. Three days after the withdrawal, plasmatic sodium levels began to increase (128 mmol/L) and returned to normal after 6 days (133 mmol/L). Although hyponatremia is not mentioned in the acyclovir summary of product characteristics, 2 reports in literature suggest that this drug could be a causative agent of hyponatremia. We believe that there is a relationship between acyclovir and hyponatremia. Application of the Karch and Lasagna algorithm to assess the causality of the reaction induced by acyclovir revealed the relationship to be possible.

Autosomal Dominant Polycystic Kidney Disease: What Do We Need To Know For Counselling?

In the new millennium, few kidney diseases changed their perspectives as much as autosomal dominant polycystic kidney disease (ADPKD). New diagnostic approaches, including the evaluation of renal or liver volume by computerised tomography (CT) scan, the detection of cyst infections by positron emission tomography (PET) scan, and new therapeutic approaches (including vaptans, mTOR inhibitors, and somatostatin analogues) pose new clinical and ethical dilemmas. Therefore, the analysis of the recent advances offers an occasion for reviewing our counselling policy. The aim of this narrative review is to discuss a few crucial points concerning counselling in ADPKD: should all ADPKD patients undergo genetic testing for characterisation of the involved gene? What is the role of prenatal counselling and preimplantation selection? Should all ADPKD patients be followed in a nephrology clinic? Which imaging to use in which patients? Whom should we treat, when, and by which drugs, and how to communicate the treatment options? The working conclusions highlight the trends towards earlier referral of ADPKD patients, the importance of offering the diet options, including low-salt, high-water intake, difficult to follow, but devoid of side-effects, and the expectancy for the new therapeutic options, alone or in combination, aimed at reduction of cyst volume and/or control of cyst growth.

Does increased water intake prevent disease progression in autosomal dominant polycystic kidney disease?

The clinical effects of increased water intake on autosomal dominant polycystic kidney disease (ADPKD) progression are unknown. ADPKD patients with creatinine clearance ≧ 50 mL/min/1.73 m(2) were divided into high (H-, n = 18) and free (F-, n = 16) water-intake groups, mainly according to their preference. Prior to the study, 30 patients underwent annual evaluation of total kidney volume (TKV) and 24-h urine for an average of 33 months. During the 1-year study period, TKV and 24-h urine were analyzed at the beginning and end of the study and every 4 months, respectively. During the pre-study period, urine volume (UV) in the H-group was higher (P = 0.034), but TKV and kidney function and their slopes were not significantly different between the two groups. After the study commenced, UV further increased (P < 0.001) in the H-group but not in the F-group. During the study period, TKV and kidney function slopes were not significantly different between the two groups (primary endpoint). Plasma copeptin was lower (P = 0.024) in the H-group than in the F-group. TKV and kidney function slopes became worse (P = 0.047 and 0.011, respectively) after high water intake (H-group) but not in the F-group. High UV was associated with increased urine sodium, and urine sodium positively correlated with the % TKV slope (P = 0.014). Although the main endpoint was not significant, high water intake enhanced disease progression in the H-group when compared with the pre-study period. These findings necessitate a long-term randomized study before drawing a final conclusion.

Effects of changes in water intake on mood of high and low drinkers.

ObjectiveTo evaluate the effects of a change in water intake on mood and sensation in 22 habitual high-volume (HIGH; 2-4 L/d) and 30 low-volume (LOW; <1.2 L/d) drinkers who were asked to respectively decrease and increase their daily water intake.MethodDuring baseline HIGH consumed 2.5 L and LOW 1 L of water/day. During 3 controlled intervention days HIGH's water intake was restricted to 1 L/day whereas LOW's was increased to 2.5 L water/day. Several mood scales (Bond & Lader Visual Analog Scale (VAS), Profile of Mood States, Karolinska Sleepiness Scale, Thirst & Emotional VAS) were administered at different time points during the study. ANOVA including intervention, time point and intervention by time point as fixed effects on mean values (i.e.; baseline data vs. mean of 3 intervention days) for each mood scale was performed.ResultsAt baseline HIGH and LOW were comparable in mood state, except for thirst scores (estimate = 17.16, p<0.001) and POMS depression-dejection scores (estimate = 0.55, p<0.05) which were both higher in the HIGH vs. LOW. In HIGH the restricted water intake resulted in a significant increase in thirst (p<0.001) and a decrease in contentedness (p<0.05), calmness (p<0.01), positive emotions (p<0.05) and vigor/activity (p<0.001). In LOW, increased water consumption resulted in a significant decrease in fatigue/inertia (p<0.001), confusion/bewilderment (p = 0.05) and thirst (p<0.001) and a trend to lower sleepiness (p = 0.07) compared to baseline.ConclusionIncreasing water intake has beneficial effects in LOW, especially sleep/wake feelings, whereas decreasing water intake has detrimental effects on HIGH's mood. These deleterious effects in HIGH were observed in some sleep/wake moods as well as calmness, satisfaction and positive emotions.

Use of NaHCO3 and MgO as additives for sheep fed only pasture for a restricted period of time per day: effects on intake, digestion and the rumen environment

Effects of NaHCO3 and MgO buffer addition on intake and digestive utilization of a pasture were studied in wethers allowed a restricted time of access to forage. Twelve wethers housed in metabolic cages and fed fresh forage (predominantly Lotus corniculatus) ad libitum for 6 h/d were randomly assigned to one of the following treatments: a control forage without buffer (C) or a forage plus buffer composed of a mixture of 750 g/kg NaHCO3 and 250 g/kg MgO at 20 g/kg dry matter intake (B). Feeding behaviour, feed and water intake and digestibility, urine output, Na urine elimination, kinetics of passage, ruminal pH and ammonia concentration, N balance and ruminal microbial N synthesis were determined in vivo, and the ruminal liquor activity was evaluated in vitro by fermentation of wheat straw. Addition of buffer increased total water intake (p = 0.05), Na urinary output (p = 0.01), purine derivative excretion in urine (p = 0.05) and tended to decrease mean total retention time in the digestive tract (p = 0.09). However, buffer addition increased ruminal pH (p < 0.001) and tended to decrease the ammonia concentration (p = 0.05). That use of buffer decreased ruminal activity was evidenced by a lower volume of gas produced in vitro (p = 0.01) possibly due to a lower microbial concentration in rumen liquor. The higher rumen dilution rate, likely due to a higher water intake, seems to have been the key driver of the actions of buffer supplementation on the rumen environment. Moreover, addition of NaHCO3 led to an increased urinary Na excretion, which should be considered due to its likely negative environmental impacts.

Effects of short-term supplementation of erythritol-salt on urinary electrolyte excretion in rats

Purpose: This study was conducted in order to investigate the diuretic effects of Erythritol (ET) salt on urinary electrolyte excretion in Sprague-Dawley Rats. Methods: Animals were divided into two groups: Salt group (n = 7) and Salt + ET fed group (n = 7). Animals were provided food and water ad libitum. Supplements were administered orally to animals for one week. Results: Body weights were not statistically different between groups either on Day 1 or Day 7. However, water consumption of the Salt + ET group was significantly higher than that of the Salt group on Day 1 and Day 7. Urine volume of the Salt + ET group was approximately 27% and 38% higher than that of the Salt group on Day 1 and Day 7. In addition, we found that the total amounts of urinary electrolytes, such as sodium and potassium, of the Salt + ET group were significantly higher than those of the Salt group on Day 7. We also found that serum electrolyte concentrations did not differ between two groups. These results demonstrated that salt intake with ET was effective in increasing urinary electrolyte excretion, which might be caused by higher water intake and diuretic effect inhibiting reabsorption of water, sodium, and potassium in renal tubules. Conclusion: The results suggest that short-term supplementation of ET salt can be a potential diuretic agent by inhibiting sodium and potassium reabsorption and inducing loss of water.