title: A randomized trial to assess the potential of different beverages to affect hydration status: development of a beverage hydration index.
abstract: BACKGROUND
  The identification of beverages that promote longer-term fluid retention and maintenance of fluid balance is of real clinical and practical benefit in situations in which free access to fluids is limited or when frequent breaks for urination are not desirable. The postingestion diuretic response is likely to be influenced by several beverage characteristics, including the volume ingested, energy density, electrolyte content, and the presence of diuretic agents.
  
  
  OBJECTIVE
  This study investigated the effects of 13 different commonly consumed drinks on urine output and fluid balance when ingested in a euhydrated state, with a view to establishing a beverage hydration index (BHI), i.e., the volume of urine produced after drinking expressed relative to a standard treatment (still water) for each beverage.
  
  
  METHODS
  Each subject (n = 72, euhydrated and fasted male subjects) ingested 1 L still water or 1 of 3 other commercially available beverages over a period of 30 min. Urine output was then collected for the subsequent 4 h. The BHI was corrected for the water content of drinks and was calculated as the amount of water retained at 2 h after ingestion relative to that observed after the ingestion of still water.
  
  
  RESULTS
  Total urine masses (mean ± SD) over 4 h were smaller than the still-water control (1337 ± 330 g) after an oral rehydration solution (ORS) (1038 ± 333 g, P < 0.001), full-fat milk (1052 ± 267 g, P < 0.001), and skimmed milk (1049 ± 334 g, P < 0.001). Cumulative urine output at 4 h after ingestion of cola, diet cola, hot tea, iced tea, coffee, lager, orange juice, sparkling water, and a sports drink were not different from the response to water ingestion. The mean BHI at 2 h was 1.54 ± 0.74 for the ORS, 1.50 ± 0.58 for full-fat milk, and 1.58 ± 0.60 for skimmed milk.
  
  
  CONCLUSIONS
  BHI may be a useful measure to identify the short-term hydration potential of different beverages when ingested in a euhydrated state. This trial was registered at www.isrctn.com as ISRCTN13014105.
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom; r.j.maughan@lboro.ac.uk.
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Maughan
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom;
authors.forename: Phillip
authors.initials: P
authors.lastname: Watson
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom;
authors.forename: Philip Aa
authors.initials: PA
authors.lastname: Cordery
authors.affiliation: School of Sport, Health and Exercise Sciences, Bangor University, Bangor, United Kingdom; and.
authors.forename: Neil P
authors.initials: NP
authors.lastname: Walsh
authors.affiliation: School of Sport, Health and Exercise Sciences, Bangor University, Bangor, United Kingdom; and.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Oliver
authors.affiliation: School of Sport, Health and Exercise Sciences, Bangor University, Bangor, United Kingdom; and.
authors.forename: Alberto
authors.initials: A
authors.lastname: Dolci
authors.affiliation: School of Sport, University of Stirling, Stirling, United Kingdom.
authors.forename: Nidia
authors.initials: N
authors.lastname: Rodriguez-Sanchez
authors.affiliation: School of Sport, University of Stirling, Stirling, United Kingdom.
authors.forename: Stuart Dr
authors.identifier: http://orcid.org/0000-0002-1622-3044
authors.initials: SD
authors.lastname: Galloway
mesh_terms: D000328:Adult; D000818:Animals; D001628:Beverages; D003681:Dehydration / Q000517:prevention & control* / Q000652:urine; D004326:Drinking; D005440:Fluid Therapy; D006801:Humans; D008297:Male; D013997:Time Factors; D014554:Urination; D014867:Water; D014882:Water-Electrolyte Balance; D055815:Young Adult
chemical_list: D014867:Water
keywords: dehydration; electrolytes; euhydration; fluid balance; gastric emptying; intestinal absorption; macronutrients; rehydration; renal excretion; urine