Effects of changes in hydration on protein, glucose and lipid metabolism in man: impact on health

Abstract

Alterations of cell volume induced by changes of extracellular osmolality have been reported to regulate intracellular metabolic pathways. Hypo-osmotic cell swelling counteracts proteolysis and glycogen breakdown in the liver, whereas hyperosmotic cell shrinkage promotes protein breakdown, glycolysis and glycogenolysis. To investigate the effect of acute changes of extracellular osmolality on whole-body protein, glucose and lipid metabolism in vivo, we studied 10 male subjects during three conditions: (i) hyperosmolality was induced by fluid restriction and intravenous infusion of hypertonic NaCl (2-5%, wt/vol) during 17 h; (ii) hypo-osmolality was produced by intravenous administration of desmopressin, liberal water drinking and infusion of hypotonic saline (0.4%); and (iii) the iso-osmolality study comprised oral water intake ad libitum. Plasma osmolality increased from 28571 to 29671 mosm/kg (Po0.001during hyperosmolality, and decreased from 28671 to 26571 mosm/kg during hypo-osmolality (Po0.001). Total body leucine flux ([1-13 C]leucine infusion technique), reflecting whole-body protein breakdown, as well as whole-body leucine oxidation rate (irreversible loss of amino acids) decreased significantly during hypo-osmolality. The glucose metabolic clearance rate during hyperinsulinaemic-euglycemic clamping increased significantly less during hypo-osmolality than iso-osmolality, indicating diminished peripheral insulin sensitivity. Glycerol turnover (2-[ 13 C]glycerol infusion technique), reflecting whole-body lipolysis, increased significantly during hypo-osmolar conditions. The results demonstrate that the metabolic adaptation to acute hypo-osmolality resembles that of acute fasting, that is, it results in protein sparing associated with increased lipolysis, ketogenesis and lipid oxidation and impaired insulin sensitivity of glucose metabolism.

Examination of the effects of arsenic on glucose homeostasis in cell culture and animal studies: Development of a mouse model for arsenic-induced diabetes

“…In vitro studies have suggested that dehydration on the cellular level may disrupt insulin signaling and glucose metabolism via mechanisms related to cell volume Haussinger, 2003, 2000). However, a recent study suggests that dehydration does not significantly impair insulin sensitivity or glucose metabolism in human subjects (Keller et al, 2003). With no clear consensus regarding the effects of dehydration on glucose tolerance, future studies should address this potential confounding factor when examining the effects of chronic exposures to iAs or other arsenicals in drinking water.…”

A proposed method for assessing plasma hypertonicity in vivo

“…Plasma hypertonicity, elevated plasma concentrations of solutes that draw fluid out of cells by osmosis, may promote obesity, related metabolic dysregulation and chronic disease (Haussinger et al, 1993;Keller et al, 2003;Stookey et al, 2004a, b). Epidemiologic research to pursue this possibility requires indices of mild hypertonicity that can be used in cross-sectional or observational studies of incident disease in initially healthy, free-living individuals.…”

Pengaruh asupan air putih terhadap berat badan, indeks massa tubuh, dan persen lemak tubuh pada remaja putri yang mengalami gizi lebih

“…Setelah satu tahun, pengeluaran energi akan mencapai 73.000 kJ (17.400 kkal) yang merupakan energi yang terkandung dalam 2,4 kg jaringan adiposa. 11,13 Penurunan berat badan, IMT, dan persen lemak tubuh dengan meningkatkan konsumsi air putih sebelum makan sulit dilakukan karena menimbulkan ketidaknyamanan. Upaya penurunan berat badan, IMT dan persen lemak tubuh perlu dilakukan melalui kombinasi antara pola makan dan aktivitas fisik.…”