Water Intake and Markers of Hydration Are Related to Cardiometabolic Risk Biomarkers in Community-Dwelling Older Adults: A Cross-Sectional Analysis

Fluid and electrolyte balance following consumption of skimmed milk and a plant-based soya beverage at rest in euhydrated males

PURPOSE

Cow's milk is one of the most hydrating beverages, but many individuals choose not to consume dairy in their diet due to intolerance, allergy, or dietary preference. Milk is commonly replaced with plant-based beverages, including soya which has the most comparable protein content, but little is known about their hydration potential. This study compared fluid and electrolyte balance responses between a soya beverage and skimmed cow's milk.

METHODS

Ten healthy males [age 27 (6) y; body mass index 24.6 (2.3) kg/m2] completed two randomised counterbalanced trials, involving consuming 1000 mL water from approximately isocaloric amounts of skimmed cow's milk (MILK) or a sweetened soya beverage (SOYA), in four aliquots over 30 min in a euhydrated fasted state. Volume, specific gravity, and electrolyte (sodium, potassium, chloride) concentrations were determined in total-void urine samples collected pre-/post-beverage ingestion, and hourly for 180 min thereafter. Hunger, thirst, nausea and stomach fullness were rated proximal to urine samples.

RESULTS

Total urine mass (MILK, 986 ± 254 g; SOYA, 950 ± 248 g; P = 0.435) and urine specific gravity (P = 0.156) did not differ between trials. Potassium balance was greater in SOYA 0-180 min post-beverage (P ≤ 0.013), whilst chloride balance was greater in MILK 0-120 min post-beverage (P ≤ 0.036). Sodium balance (P = 0.258), total electrolyte balance (P = 0.258), and subjective measures (P ≥ 0.139) were not different between trials.

CONCLUSION

Replacing cow's milk with a soya beverage did not negatively impact fluid balance in healthy young males, making it a viable option for those who choose not to consume dairy in their diet.

The Amount of Fluid Intake among Pregnant Women in China Increases with Pregnancy Progression: A Prospective Cohort Study

Fluid intake and hydration status during pregnancy may have influences on maternal and infant health. However, few studies have recorded and analyzed total fluid intake (TFI) levels during the whole pregnancy. This study mainly aimed to investigate the TFI levels of pregnant women in three trimesters, and further to assess their hydration status. The relationships of TFI and hydration status were also analyzed. A convenience sampling method was used to recruit pregnant women from the Haikou Maternity and Child Health Hospital in China in this prospective cohort study. A 7-day 24 h fluid intake questionnaire was used for recording the fluid intake of the participants in their three trimesters. Fasting blood samples and first morning urine samples were also collected and tested. Hydration status was evaluated using urine osmolality. Finally, 142 pregnant women completed the study. The median TFIs in the first, second, and third trimesters were 1336, 1477, and 1584 mL, respectively. The TFI levels increased with pregnancy progression (χ2 = 134.155, p < 0.05). Out of 142 participants, 100.0%, 97.2%, and 85.2% of participants did not reach the recommendation amount for an adequate TFI among Chinese pregnant women in the three trimesters, respectively (χ2 = 29.840, p < 0.05). Plain water was the main source of fluid intake, accounting for 92.0%, 94.2%, and 93.4% of TFI, respectively. The median values of dairy product intake were 61, 57, and 59 mL in the three trimesters. The frequency of participants without an optimal hydration status in the three trimesters was 71.8%, 76.1%, and 83.1%, respectively (χ2 = 29.909, p < 0.05). The participants of each trimester were divided into four groups according to quartiles of TFI, including participants with a lower fluid intake (LFI1 and LFI2) and higher fluid intake (HFI1 and HFI2). As the TFI values increased from the LFI1 group to the HFI2 group, the urine osmolality decreased (all p < 0.05). Moderate-intensity negative correlations were found between urine osmolality, hydration status, and TFI (all p < 0.05). It is suggested that fluid intake strategies should be promoted and health education should be conducted to improve the hydration status of pregnant women.

Ex vivo LPS-stimulated cytokine production is associated with hydration status in community-dwelling middle-to-older-aged adults

PURPOSE

Suboptimal hydration has been linked to a variety of adverse health outcomes. Few studies have examined the impact of hydration status on immune function, a plausible physiological mechanism underlying these associations. Therefore, we tested how variation in hydration status was associated with circulating pro-inflammatory cytokine levels and ex vivo lipopolysaccharide (LPS)-stimulated pro-inflammatory cytokine production.

METHODS

Blood samples were obtained from a community sample of healthy middle-to-older-aged adults (N = 72). These samples were used to assess serum osmolality, a biomarker of hydration status, and markers of immune function including circulating pro-inflammatory cytokines and stimulated pro-inflammatory cytokine production after 4 and 24 h of incubation with LPS. Multiple linear regressions were used to test the association between serum osmolality (as a continuous variable) and markers of immune function at baseline and after 4 and 24 h adjusting for age, sex, and BMI. These models were re-estimated with serum osmolality dichotomized at the cut-off for dehydration (> 300 mOsm/kg).

RESULTS

While not significantly associated with circulating cytokines (B = - 0.03, p = 0.09), serum osmolality was negatively associated with both 4 h (B = - 0.05, p = 0.048) and 24 h (B = - 0.05, p = 0.03) stimulated cytokine production when controlling for age, sex, and BMI. Similarly, dehydration was associated with significantly lower cytokine production at both 4 h (B = - 0.54, p = 0.02) and 24 h (B = - 0.51, p = 0.02) compared to adequate hydration.

CONCLUSION

These findings suggest that dehydration may be associated with suppressed immune function in generally healthy middle-to-older aged community-dwelling adults. Further longitudinal research is needed to more clearly define the role of hydration in immune function.

Urinary Hydration Biomarkers and Water Sources in Older Adults with Neurocognitive Disorder

The risk of dehydration in older adults with neurocognitive disorder (NCD) is controversial. The purpose of this study was to assess hydration status, its determinants, and water intake sources in older adults with NCD. A sample of 30 participants (≥60 years) was included. Sociodemographic, clinical data and one 24-h urine sample were collected. Urinary osmolality, sodium, potassium, volume, and creatinine were quantified. Inadequate hydration status corresponded to urine osmolality > 500 mOsm/Kg, or a negative Free Water Reserve (FWR). Two 24-h food recalls were used to assess dietary intake and water sources. The adequacy of total water intake (TWI) was estimated according to EFSA. The contribution of food and beverages to TWI was calculated, and their associations with the urinary osmolality median were tested. Of the total number of participants, 30% were classified as having inadequate hydration status, with no differences between sexes. Regarding TWI, 68.4% of women and 77.8% of men did not reach the reference values. Water (23%), followed by soup (17%), contributed the most to TWI, while vegetables (2%) and alcoholic/other beverages (3%) contributed the least. According to the median urinary osmolality, there was no significant difference in sociodemographic/clinical characteristics. It is critical not to overlook hydration in this vulnerable population.

THIRSTY FOR FRUCTOSE: Arginine Vasopressin, Fructose, and the Pathogenesis of Metabolic and Renal Disease

We review the pathways by which arginine vasopressin (AVP) and hydration influence the sequelae of the metabolic syndrome induced by high fructose consumption. AVP and inadequate hydration have been shown to worsen the severity of two phenotypes associated with metabolic syndrome induced by high fructose intake-enhanced lipogenesis and insulin resistance. These findings have implications for those who frequently consume sweeteners such as high fructose corn syrup (HFCS). Patients with metabolic syndrome are at higher risk for microalbuminuria and/or chronic kidney disease; however, it is difficult to discriminate the detrimental renal effects of the metabolic syndrome from those of hypertension, impaired glucose metabolism, and obesity. It is not surprising the prevalence of chronic renal insufficiency is growing hand in hand with obesity, insulin resistance, and metabolic syndrome in those who consume large amounts of fructose. Higher AVP levels and low hydration status worsen the renal insufficiency found in patients with metabolic syndrome. This inter-relationship has public health consequences, especially among underserved populations who perform physical labor in environments that place them at risk for dehydration. MesoAmerican endemic nephropathy is a type of chronic kidney disease highly prevalent in hot ambient climates from southwest Mexico through Latin America. There is growing evidence that this public health crisis is being spurred by greater fructose consumption in the face of dehydration and increased dehydration-dependent vasopressin secretion. Work is needed at unraveling the mechanism(s) by which fructose consumption and increased AVP levels can worsen the renal disease associated with components of the metabolic syndrome.

Using Water Intake Dietary Recall Data to Provide a Window into US Water Insecurity

BACKGROUND

In the United States, problems with the provision of safe, affordable water have resulted in an increasing number of adults who avoid their tap water, which could indicate underlying water insecurity. Dietary recalls provide critical nutritional surveillance data, yet have been underexplored as a water insecurity monitoring tool.

OBJECTIVES

This article aims to demonstrate how water intake variables from dietary recall data relate to and predict a key water insecurity proxy, that is, tap water avoidance.

METHODS

Using 2005-2018 NHANES data from 32,329 adults, I examine distributions and trends of mean intakes of total, plain (sum of tap and bottled water), tap, and bottled water, and percentage consuming no tap and exclusive bottled water. Second, I use multiple linear and logistic regressions to test how tap water avoidance relates to plain water intake and sugar-sweetened beverage (SSB) consumption. Next, I use receiver operating characteristics (ROC) curves to test the predictive accuracy of no plain water, no tap, and exclusive bottled water intake, and varying percentages of plain water consumed from tap water compared with tap water avoidance.

RESULTS

Trends indicate increasing plain water intake between 2005 and 2018, driven by increasing bottled water intake. In 2017-18, 51.4% of adults did not drink tap water on a given day, whereas 35.8% exclusively consumed bottled water. Adults who avoided their tap water consumed less tap and plain water, and significantly more bottled water and SSBs on a given day. No tap intake and categories of tap water intake produced 77% and 78% areas under the ROC curve in predicting tap water avoidance.

CONCLUSIONS

This study demonstrates that water intake variables from dietary recalls can be used to accurately predict tap water avoidance and provide a window into water insecurity. Growing reliance on bottled water could indicate increasing concerns about tap water.