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The Effect of Hydration Status on Glycemic Control and Appetite Regulation

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT02841449
Recruitment Status : Completed
First Posted : July 22, 2016
Results First Posted : June 22, 2020
Last Update Posted : June 22, 2020
Sponsor:
Collaborators:
University of Bristol
Loughborough University
European Hydration Institute
Economic and Social Research Council, United Kingdom
Lund University
Information provided by (Responsible Party):
Harriet Carroll, University of Bath

Brief Summary:

The aim of this study is to investigate whether hydration status affects blood sugar control and appetite regulation. In order to do this, participants will undergo a monitoring phase whereby their weight, diet and physical activity are monitored, followed by a dehydration protocol involving fluid restriction and sitting in a heat tent. In one arm of the trial, participants will remain dehydrated for the remainder of the day (i.e. after the heat tent) by having their fluid intake restricted, and in the other arm of the trial, participants will be rehydrated by consuming the necessary amount of plain water. All participants will undergo both arms of the trial, the order of which will be chosen randomly.

Several measures will be taken throughout the trial. Before participants go into the heat tent, they will provide a urine sample (for baseline hydration status as indicated by urine osmolality), a blood sample (for glucose, insulin, arginine vasopressin,/copeptin, ghrelin and serum osmolality and plasma volume), and have a peripheral quantitative computer tomography scan of their thigh to indicate muscle size. On the day proceeding the heat tent, participants will have these measures repeated, along with metabolic rate before consuming a 75 g glucose drink, followed by 15 minutely blood samples and hourly metabolic rate measures for 120 minutes (i.e. an oral glucose tolerance test; OGTT). Following this, participants will be presented with a large bowl of pasta and sauce and will be instructed to eat until satisfied (maximum 30 min). Blood samples will be taken every 10 minutes for 60 minutes following the meal.

Participants also have the option to opt-in to have a muscle biopsy taken. This will be taken before and ~120 minutes after the glucose drink.


Condition or disease Intervention/treatment Phase
Healthy Behavioral: Hypohydrated Behavioral: Rehydrated Not Applicable

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 16 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: The Effect of Hydration Status on Glycemic Control and Appetite Regulation
Actual Study Start Date : July 2016
Actual Primary Completion Date : January 2017
Actual Study Completion Date : January 2017

Arm Intervention/treatment
Experimental: Hypohydrated
After being dehydrated in the heat tent, participants in this trial arm will be given 3 mL/kg lean body mass to consume over the rest of the day (e.g. a 75 kg participant with a body composition of 85 % fat free mass would consume 191 mL water [63.75 kg * 3 mL])
Behavioral: Hypohydrated
Participants remain hypohydrated after the heat tent procedure

Experimental: Rehydrated
After being dehydrated in the heat tent, participants in this trial arm will be given 40 mL/kg lean body mass plus 150 % of their water losses (from the heat tent procedure) over the rest of the day (e.g. a 75 kg participant with a body composition of 85 % fat free mass and lost 1 % of their body mass in the heat tent (0.75 kg) would consume 2550 mL [63.75 kg * 40 mL] + 1125 mL [750 g * 1.5], totalling 3675 mL).
Behavioral: Rehydrated
Participants rehydrate after the heat tent procedure




Primary Outcome Measures :
  1. Glycemic Response [ Time Frame: Measured on day 5 on both trial arms, using the blood sample drawn before the glucose beverage is consumed and the blood samples drawn for the subsequent 120 minutes ]
    Primary analysis is time trends (i.e. ANOVA effects), supported by indices of the glycemic response (e.g. iAUC, time to peak). Blood was taken pre-muscle biopsy (if participants opted in for a muscle biopsy), before consuming the glucose drink (after the biopsy, where applicable), then at 15 minutely samples for 120 minutes. After the meal test, blood was drawn at 10 minutely intervals for 60 minutes, starting 30 minutes after commencement of eating.


Secondary Outcome Measures :
  1. Insulinemic Response [ Time Frame: Measured on day 5 on both trial arms, using the blood sample drawn before the glucose beverage is consumed and the blood samples drawn for the subsequent 120 minutes ]
    Primary analysis is time trends (i.e. ANOVA effects), supported by indices of the insulinemic response (e.g. iAUC, time to peak). Bloods drawn at pre-biopsy, pre-OGTT, 15, 30, 45, 60, 90, 120 min and 0, 30, 60 minutes after the ad libitum meal test.

  2. Arginine Vasopressin and Copeptin Response [ Time Frame: Measured on day 5 on both trial arms, using the blood sample drawn before the glucose beverage is consumed and the blood samples drawn for the subsequent 120 minutes (please note: may measure copeptin as a marker of arginine vasopressin) ]
    Primary analysis is time trends (i.e. ANOVA effects), supported by indices of the response trends (e.g. iAUC, time to peak). Bloods drawn pre-biopsy, pre-OGTT, and then 15 minutely for 120 minutes, and then 10 minutely after the ad libitum meal test.

  3. Ghrelin Response [ Time Frame: Measured on day 5 on both trial arms, using the blood sample drawn before the participant starts eating the buffet and the subsequent post-buffet blood samples ]
    Primary analysis is time trends (i.e. ANOVA effects), supported by indices of the response trend (e.g. iAUC, time to peak). Due to funding limitations, we only took one 60 minute postprandial measure of ghrelin.

  4. Energy Intake [ Time Frame: Measured on day 5 on both trial arms from the pasta test meal ]
    Differences in energy intake between the hypohydrated and rehydrated groups (two-tailed t-test)

  5. Metabolic Rate [ Time Frame: Using the metabolic rate data collected on day 5 on both trial arms ]
    Comparing respiratory quotient and metabolic rate

  6. Subjective Appetite Ratings [ Time Frame: Collected on day 5 of both trial arms during the buffet ]
    Comparing appetite response. Scales were visual analogue scales of hunger, fullness, how much you feel you can eat, thirst, and desire for sweet, salty, savoury and fatty foods. Scales were 0-100 mm vertical lines which participants marked where 0 = not at all/no desire and 100 = extremely/very high desire)

  7. Muscle Volume [ Time Frame: pQCT scans on day 4 of the trial before the dehydration protocol in the heat tent, and on day 5 before the OGTT ]
    Comparing muscle size in the dehydrated and rehydrated state.Taken from the pQCT scans

  8. Body Water Content [ Time Frame: Daily (i.e. 5 consecutive days for each trial arm) ]
    Taken from bioelectrical impedance weighing scales


Other Outcome Measures:
  1. Serum Osmolality [ Time Frame: Measured from the blood samples on day 4 and day 5 on both trial arms ]
    Change from baseline

  2. Plasma Volume [ Time Frame: Measured from the blood samples on day 4 and day 5 on both trial arms ]
    Error in plasma volume measurement during the study invalidated the data

  3. Other Metabolites [ Time Frame: Collected from the blood samples throughout day 5 of both trial arms ]
    Creatinine, cholesterol, triglycerides (if funds allow). No funds, not measured

  4. Muscle Biopsy Measures [ Time Frame: Using the muscle biopsy samples from participants who opted-in, pre- and post-OGTT on day 5 of each trial ]
    These are pilot data for future studies. Muscle glycogen content will be looked at

  5. Psychological Appetite Tests [ Time Frame: Within the 30 minutes before the ad libitum pasta meal ]
    These are pilot data for future hypotheses looking at subconscious food cues.



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Ages Eligible for Study:   18 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Healthy male or female
  • Aged 18-60 years
  • Able and willing to give informed consent

Exclusion Criteria:

  • Any known metabolic or glucose disorder
  • Taking necessary medication (other than contraceptives) or supplements that are known to affect glycaemic control (e.g. chromium, PUFAs)
  • Current alcohol or drug dependency
  • Aged < 18 years, or > 60 years; pregnant or breastfeeding
  • Any other factors which are deemed to have the potential to cause harm to the participant and/or could introduce bias into the study

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02841449


Locations
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United Kingdom
University of Bath
Bath, Somerset, United Kingdom, BA2 7AY
Sponsors and Collaborators
University of Bath
University of Bristol
Loughborough University
European Hydration Institute
Economic and Social Research Council, United Kingdom
Lund University
Investigators
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Principal Investigator: Harriet A Carroll, MRes University of Bath
Publications:
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Responsible Party: Harriet Carroll, PhD Student, University of Bath
ClinicalTrials.gov Identifier: NCT02841449    
Other Study ID Numbers: 16/SW/0057
First Posted: July 22, 2016    Key Record Dates
Results First Posted: June 22, 2020
Last Update Posted: June 22, 2020
Last Verified: June 2020
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Yes
Plan Description: Anonymised data will be shared
Supporting Materials: Study Protocol
Clinical Study Report (CSR)
Time Frame: Available (no time restrictions)
Access Criteria: Open access; doi URL below for hydration-glycaemia data, related report: https://doi.org/10.1152/japplphysiol.00771.2018; data for hydration-appetite: https://doi.org/10.15125/BATH-00719 and related report: https://doi.org/10.1016/j.physbeh.2019.112725
URL: https://doi.org/10.15125/BATH-00547
Keywords provided by Harriet Carroll, University of Bath:
Hydration
Glycemic control
Appetite
Endocrinology