Understanding the hydration potential of commonly consumed drinks

ISRCTN ISRCTN13014105
DOI https://doi.org/10.1186/ISRCTN13014105
Secondary identifying numbers N/A
Submission date
20/03/2015
Registration date
23/03/2015
Last edited
02/03/2016
Recruitment status
No longer recruiting
Overall study status
Completed
Condition category
Other
Prospectively registered
Protocol
Statistical analysis plan
Results
Individual participant data

Plain English Summary

Background and study aims
The volume and composition of any drink makes a difference to how much of the volume is retained by the body and how much is excreted as urine. The pattern of urine output in the hours after drinking a fixed volume of a drink provides information about the impact of that drink on the body’s ability to retain fluid (i.e., how well it can act as a hydration drink). While there is some knowledge about the impact of different drinks on urine output, no study has set out to investigate the hydrating potential of a wide range of drinks that are commonly drank in daily life. This study therefore aims to determine the hydrating potential of a range of drinks. The knowledge gained from this project should allow the researchers to develop a hydration index for different drinks (much in the same way as a glycaemic index has been developed for different foods). This hydration index information could be developed further for use with athletes, older adults, or other clinical populations where fluid replacement may be an important aspect of daily life.

Who can participate?
Healthy moderately active men, aged 18-35, in Stirling, Bangor or Loughborough.

What does the study involve?
You are required to attend the laboratory on four occasions. You should avoid participating in any intense physical activity on the day before or morning of the laboratory visits. No alcohol should be consumed for at least 24 hours and no food for at least 10 hours before entering the laboratory. One hour before entering the laboratory you will drink 500 ml of water. You will provide a urine sample and a blood sample will be taken from a vein in your arm. After this you will be weighed and then asked to drink 1L (4 x 250 ml) of a test drink (a different drink on each of the four lab visits). The test drinks include still water and others from the following: sparkling mineral water, Coca-Cola, diet cola (Coca-Cola Zero), sports drink (Powerade), oral rehydration solution (Dioralyte blackcurrant flavour), fruit juice (orange juice), beer, coffee, tea, cold tea, full fat milk, skimmed milk. Urine samples will then be collected each hour over a period of 4 hours.

What are the possible benefits and risks of participating?
You shall benefit from participating in the study by receiving your own, personal hydration index profile. Results of the study shall be used in order to inform practice by developing a hydration index. You shall be required to drink 1L of fluid over a 30-minute period on each lab visit. This may be uncomfortable for some people due to stomach fullness and/or frequent need to urinate, but it is an important part of this study and you will be allowed to empty your bladder when you wish. You will also experience a little discomfort when a needle is inserted into your arm to enable blood sampling. An experienced person will do this to minimise any discomfort.

Where is the study run from?
The University of Stirling, Bangor University, and Loughborough University (UK)

When is the study starting and how long is it expected to run for?
February to August 2014

Who is funding the study?
The European Hydration Institute

Who are the main contacts?
Dr Stuart Galloway (Stirling); s.d.r.galloway@stir.ac.uk
Prof Neil Walsh (Bangor); n.walsh@bangor.ac.uk
Dr Phil Watson (Loughborough); P.Watson2@lboro.ac.uk

Contact information

Dr Stuart Galloway
Scientific

Health and Exercise Sciences Research Group
University of Stirling
Stirling
FK9 4LA
United Kingdom

ORCiD logoORCID ID 0000-0002-1622-3044
Phone +44 (0)1786466494
Email s.d.r.galloway@stir.ac.uk
Prof Neil Walsh
Scientific

School of Sport, Health and Exercise Sciences
Bangor University
Gwynedd
Bangor
LL57 2DG
United Kingdom

Phone +44 (0)1248383480
Email n.walsh@bangor.ac.uk
Dr Phil Watson
Scientific

School of Sport, Exercise and Health Sciences
Loughborough University
Epinal Way
Loughborough
LE11 3TU
United Kingdom

Phone +44 (0)1509222759
Email P.Watson2@lboro.ac.uk

Study information

Study designRandomised cross-over study
Primary study designInterventional
Secondary study designRandomised cross over trial
Study setting(s)Other
Study typeOther
Scientific titleDevelopment of an hydration index: a randomized trial to assess the potential of different beverages to affect hydration status in adult males
Study hypothesisWe hypothesized that the macronutrient content and electrolyte content of different drinks would impact upon fluid delivery and retention following the ingestion of a fixed volume of fluid. We hypothesized that differences in the capacity to maintain hydration status could be used to develop an hydration index for a range of different beverages.
Ethics approval(s)The study was approved by the ethics committees of:
1. University of Stirling (School of Sport Research Ethics Committee), 07/02/2014, ref: SSREC #670
2. Bangor University (School of Sport, Health and Exercise Sciences Ethics Committee), 14/02/2014, ref: S/PhD13-13/14
3. Loughborough University (Ethical Approvals [Human Participants] Sub-Committee of the Loughborough University Ethics Committee), 07/01/2014, ref: R13-P221
ConditionHydration status monitoring
InterventionAfter baseline samples were collected, each participant consumed 1L of fluid over a 30-minute period (4 x 250 ml delivered at 7.5-min intervals) and hydration status was monitored at hourly intervals over the subsequent 4 hours. Participants ingested water as a control trial (Highland Spring™, Perthshire, UK) and consumed three of the following drinks in a randomised, counter-balanced order: sparkling water (Highland Spring™, Perthshire, UK), Coca-Cola® (Uxbridge, UK), Diet Coke® (Uxbridge, UK), Powerade® (Coca-Cola®, Uxbridge, UK), Dioralyte™ (Sanofi. One, Surrey, UK), orange juice (Tesco Everyday Value, Hertfordshire, UK), lager beer (Carling®, Staffordshire, UK), instant black coffee (Nescafe® Original, York, UK), hot black tea (PG tips®, Unilever, London, UK), cold black tea (PG tips®, Unilever, London, UK), whole milk (4% fat; Tesco, Hertfordshire, UK) or skimmed milk (0.1% fat; Tesco, Hertfordshire, UK). We obtained n=72 observations for water, and n=17 observations for each of the other test drinks.
Intervention typeOther
Primary outcome measure1. Net fluid balance over each hour for 4 hours (fluid ingested minus cumulative urine output)
2. Hydration Index at each hour over 4 hours (net fluid balance comparison to water as a control)
Secondary outcome measures1. Urine and serum osmolality at baseline and at each hour following fluid ingestion for 4 hours (freezing point depression method within 48 hours of sample collection)
2. Sodium and potassium net balance assessed immediately post-drinking and each hour following fluid ingestion for 4 hours (flame photometry method within 5 days of sample collection)
Overall study start date21/02/2014
Overall study end date21/08/2014

Eligibility

Participant type(s)Healthy volunteer
Age groupAdult
Lower age limit18 Years
Upper age limit35 Years
SexMale
Target number of participants72 (n=24 at each site)
Participant inclusion criteria1. Healthy male volunteers
2. Aged 18-35
3. BMI 18-27 kg/m2
4. No known cardiovascular, renal or metabolic disease
5. Moderately active
6. Moderate alcohol use
Participant exclusion criteria1. Overweight or obese (BMI >27 kg/m2)
2. Competitive athletes during competition season
3. Current or former cardiovascular, renal or metabolic disease
4. Habitual consumption of alcohol (>21 units/week) or regular (>1/week) high (10 units) intake
5. History of psychiatric illness
6. Actively seeking to gain or lose weight
7. Currently taking prescribed medication
Recruitment start date21/02/2014
Recruitment end date07/07/2014

Locations

Countries of recruitment

  • England
  • Scotland
  • United Kingdom
  • Wales

Study participating centres

University of Stirling
Health and Exercise Sciences Research Group
Stirling
FK9 4LA
United Kingdom
Bangor University
School of Sport, Health and Exercise Sciences
Gwynedd
Bangor
LL57 2DG
United Kingdom
Loughborough University
School of Sport, Exercise and Health Sciences
Epinal Way
Loughborough
LE11 3TU
United Kingdom

Sponsor information

University of Stirling (UK)
University/education

Airthrey Road
Stirling
FK9 4LA
Scotland
United Kingdom

Website www.stir.ac.uk
Bangor University (UK)
University/education

Gwynedd
Bangor
LL57 2DG
Wales
United Kingdom

Website www.bangor.ac.uk
Loughborough University (UK)
University/education

Epinal Way
Loughborough
LE11 3TU
England
United Kingdom

Website www.lboro.ac.uk
University of Stirling
Not defined

Funders

Funder type

Research organisation

European Hydration Institute

No information available

Results and Publications

Intention to publish date
Individual participant data (IPD) Intention to shareYes
IPD sharing plan summaryAvailable on request
Publication and dissemination planWe intend to present the results at a meeting organised by the funders of the research (European Hydration Institute) in London in June 2015. We also hope to publish the data in a relevant clinical journal in 2015.
IPD sharing plan

Study outputs

Output type Details Date created Date added Peer reviewed? Patient-facing?
Results article results 01/03/2016 Yes No

Editorial Notes

02/03/2016: Publication reference added.