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Trial registered on ANZCTR


Registration number
ACTRN12617001347358
Ethics application status
Approved
Date submitted
27/04/2017
Date registered
25/09/2017
Date last updated
12/11/2018
Date data sharing statement initially provided
12/11/2018
Type of registration
Prospectively registered

Titles & IDs
Public title
The effect of a dietary ketone on immunity, tolerability and performance in well-trained, healthy male cyclists.
Scientific title
The effect of 1,3-butanediol on immunity, tolerability and performance in well-trained, healthy male cyclists.
Secondary ID [1] 291788 0
Nil
Universal Trial Number (UTN)
U111-1192-4543
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Exercise-Induced immunosuppression
 303018 0
Gastrointestinal distress 303019 0
Systemic symptoms (e.g. dizziness, nausea) 303279 0
Condition category
Condition code
Inflammatory and Immune System 302477 302477 0 0
Other inflammatory or immune system disorders
Oral and Gastrointestinal 302478 302478 0 0
Normal oral and gastrointestinal development and function
Other 302708 302708 0 0
Research that is not of generic health relevance and not applicable to specific health categories listed above

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Pre-experimental tests and time trial familiarisation: Participants will arrive at the laboratory at a time of convenience and having abstained from caffeine, alcohol and strenuous exercise for the previous 24 h. Participants will be required to fast for at least four hours prior to arrival. Participants will be asked to void their bladder before their body mass (shorts only), height and sum of 8 skinfolds are measured by an International Society for the Advancement of Kinanthropometry Level 1 Accredited Anthropometrist. To determine VO2peak, participants complete a continuous incremental cycling protocol originally described by Achten and colleagues (2002) and adapted by Achten and colleagues (2003), requiring participants to start cycling at 95W with increments of 35W every 3 min until either; 1) volitional exhaustion or 2) cadence cannot be maintained >60 RPM. If the participants VO2peak is >60ml/kg/min, they will be deemed eligible for the study. Participants will re-mount the cycle ergometer, which will be switched from hyperbolic mode to linear mode, and precisely on 15 min of rest they will commence a time trial equivalent to 7kJ/kg (~25-35 min).

Compared to hyperbolic mode, which allows the cycle ergometer to produce a set power output independent of cadence, the power output in linear mode is cadence (RPM) dependant, with power (W) calculated according to the formula:

W = L x (RPM)2

Where RPM is the cadence and L is a (constant) linear factor. L will be calculated to elicit a power output of 70% Wmax at an RPM of 90.

Maximal power output (Wmax) will be calculated according to the formula
Wmax = Wfinal + (t/T) · Winc

Where Wfinal is the power output (W) of the final completed stage, t is the time achieved in the final uncompleted stage (s), T is the duration of each stage (180 s) and Winc is the workload increment (35 W).

Pre-experimental, familiarisation and experimental tests / trials will be completed on an electromagnetically braked cycle ergometer (Lode Excalibur Sport, Groningen, Netherlands). The expired gas will be collected and analysed continuously using a computerised metabolic system with mixing chamber (Parvo Medics TrueOne 2400, Salt Lake City, Utah, USA). Ventilatory thresholds (VT1 and VT2) will be estimated during the continuous incremental cycling protocol. VT1 will be inferred by the criteria of the first marked increase in VE/VO2 with no concomitant increase in VE/VCO2. VT2 will be inferred by the criteria of an increase in both VE/VO2 and VE/VCO2 and a decrease in PETCO2. Ratings of perceived exertion (RPE) (Borg scale) will be noted for each stage and heart rate will be continuously measured using short-range telemetry. The work rate equivalent to 85% VT2 will be inferred for use in the experimental procedures for performance trials.

Familiarisation trial: Three to seven days after the pre-experimental test, participants will return to the laboratory between 07:00 and 08:00h having fasted from 23:00 h the previous day. Participants will we be asked to consume a high carbohydrate diet (6g/kg) during the previous 24 hours to standardise nutritional status. Participants will be provided with dietary guidelines and asked to record their intake via written and photographic documentation. If certified, participants will be asked to repeat their dietary protocol prior to each subsequent experimental procedure. Participants will also be advised to consume 500 ml of water upon wakening to standardise hydration status. They will then provide a saliva sample (practice sample). Participants will mount the cycle ergometer and cycle for 85 min at the power output equivalent to 85% of their VT2 as determined in the pre-experimental test. Every 20 min, participants will have a ventilatory mask fitted for 3 min for gas analysis. Following completion, they will be allowed 5 min to rest and use the lavatory. Participants will re-mount the cycle ergometer, which will be switched from hyperbolic mode to linear mode, and precisely on 5 min of rest they will commence a time trial equivalent to 7kJk/g (~25-35 min).

Participants will be able to consume water ad-libitum throughout the familiarisation test. Participants will then provide a saliva sample (practice sample) following completion, after which, they will be reminded of the requirements of the experimental tests.

Experimental procedure: Five to ten days after the familiarisation test, participants will arrive at the laboratory between 06:00 and 08:00 h having fasted from 23:00 h the previous day and refrained from caffeine and alcohol for the previous 24 hours and strenuous exercise for the previous 48 h. Participants will be advised to consume 500 ml of water upon waking to standardise hydration status. Upon arrival at the lab, participants will have a cannula inserted into their antecubital vein and asked to rest quietly for ~10 min prior to initial blood and saliva samples, ketone levels and tolerability scores being collected (baseline measures). Participants will be asked to void their bladder before their body mass (shorts only) measured.

Participants will then consume a citrus flavoured drink (2ml/kg) (30 min before commencing exercise). The drink will be formulated to provide 0.35g/kg of 1,3-BD or placebo. Participants will be blinded to the inclusion of 1,3-BD. Twenty-five minutes following the intake of 1,3-BD and immediately prior to commencing exercise, blood and saliva samples, blood ketone, lactate and glucose levels will be collected. Participants will then mount the cycle ergometer and cycle 85 min 85% VT2 power output. Every 20 min, participants will have a ventilatory mask fitted for 3 min for gas analysis and RPE will be recorded. Every 30 min, blood ketones and glucose levels will be measured (capillary finger prick). After 60 min of cycling (i.e. 90 minutes following the initial intake of the citrus flavoured drink), participants will either consume an additional 2mlkg-1 citrus flavoured drink containing 0.35gkg-1 of 1,3-BD or placebo. After 85 min of cycling, participants will be allowed 5 min to rest. During this time, blood samples, blood ketone, lactate and glucose levels will be collected. Precisely on 5 min, participants will re-mount the cycle ergometer, which will be switched from hyperbolic mode to linear mode, and they will complete a TT equivalent to 7kJ/kg (~25 – 35 min) from a stationary start. Participants will be restricted to 2mlkg-1 every 15 min during exercise. Before leaving the cycle ergometer, blood samples, blood ketone, lactate and glucose levels will be collected.

Immediately afterwards, saliva samples, and tolerability scores will be collected. Participants will then remove wet clothing, towel dry themselves and have their body mass measured (shorts only) to estimate fluid loss. Participants will then be provided with 5ml/kg of water and asked to rest until 1 h post time trial when blood and saliva samples, blood ketone and glucose and tolerability scores will be collected. Following completion of the trial, participants will be provided with 400 – 600 ml of a carbohydrate drink and asked to return to the laboratory 5 – 10 days later to repeat the protocol with the alternative dietary intervention (i.e. placebo or 1,3-BD).

Safety monitoring: Participant tolerability, side-effects and abnormal haematological values will be immediately reported to a medical doctor. This study will be immediately terminated when advised by the medical doctor or following intractable symptoms after 1,3-BD consumption in 2 trial arms (i.e. 10% of trials). Participants will be followed up 3 days and 1 week after the consumption of 1,3-BD to ascertain if any adverse effects occurred. Participants will also be encouraged to report any symptoms following consumption of 1,3-BD by email, phone or text.

Common to Part A and B

Capillary blood samples for ketone, gucose and lactate monitoring: Samples will be collected from participants’ fingers using standardised techniques. The site of puncture will be cleaned with an alcohol swab then allowed to air dry. Skin puncture will occur in one quick, deliberate strike of the lancet. The first drop of blood will be wiped away, then subsequent accumulation of blood will be used in analysis. Afterwards, pressure and/or a plaster will be applied to stop further bleeding. Blood beta-hydroxybutyrate (ketone) and glucose will be measured using Freestyle Optium Neo (Abbott Diabetes Care, Victoria, Australia) and blood lactate will be measured using the Lactate 2 Pro (Akray, Japan).

Tolerability questionnaire: The questionnaire is organised in three sections as previously described by Pfeiffer et al. (2009) and adapted to include additional symptoms. Section 1 addresses upper abdominal problems; Section 2, lower abdominal problems; and Section 3, systemic problems. Each participant will be assessed on the 29 items on a 10-point scale ranging from 0, no problem at all, to 9, the worst it has ever been.

Salivary sampling and analysis: Unstimulated saliva samples will be collected. Participants will be instructed to be in a seated position, leaning forward with their head tilted down and asked to empty their mouth of any residual saliva before the timed sample collection begins. Each saliva collection will last 3 min, during which time participants will be requested to minimise orofacial movement and passively dribble into a pre-weighed vial. Samples will be weighed to estimate saliva volume (the density will be assumed to be 1.0g/ml and micro-centrifuged to remove cells and insoluble matter before storing at -20oC for later analysis. The saliva flow rate (ml/min) will be determined by dividing the volume of saliva by collection time. Saliva samples will be analysed for salivary immunoglobulin A using a commercially available ELISA kit (DRG, Germany).

Blood sampling: All blood samples will be collected via cannulation of the antecubital vein into three evacuated vacutainers, two containing tripotassium ethylene diamine tetraacetic acid (K3EDTA) and one containing no additive to obtain serum. All vacutainers will be centrifuged for 10 min at 1500 x g and 4oC. Plasma and serum will be aliquoted and stored at -80C for later analysis.

Blood Analysis
Blood cell counts: Blood collected into the K3EDTA vacutainer will be used to analyse for total and differential leukocyte counts, haematocrit and haemoglobin contents using a haematology analyser (AC.TTM 5diff analyser, Beckman Coulter, UK). All cell counts will be adjusted for plasma volume changes, with changes being estimated from haemoglobin and haematocrit values according to Dill & Costill (1974).

Whole blood culture: 2 ml of whole blood obtained from an K3EDTA vacutainer will be added to 2 ml of RPMI medium with no added stimulant (unstimulated) or stimulant (stimulated) at a concentration designed to elicit maximal lymphocyte response (final stimulant concentration will be determined with prior titration work). The stimulant that will be used will be Staphylococcal enterotoxin B from Staphylococcus aureus. The whole blood cultures will then be incubated for 24 h at 37 °C, 5 % CO2 (Thermo Fisher Scientific, Waltham, Massachusetts, USA).

Unstimulated and antigen-stimulated lymphocyte subset cell counts and activation: Whole blood cultures will be used to analyse lymphocyte cell subsets and their activation (CD69+) according to their cell surface markers CD4+, CD8+ CD25+ (T cells) via the Muse (Millipore, Darmstadt, Germany).

Unstimulated and antigen-stimulated whole blood cytokine production: Blood cultures will be centrifuged for 4 min at 13,000g in a microcentrifuge. Supernatants will be collected and stored frozen at -80 °C until analysis. Cytokines interleukin (IL)-1, IL-1ra, IL-2, IL-4, IL-8, IL-10, interferon (IFN)-? and tumour necrosis factor (TNF)-a) will be determined using a multiplex kit (Millipore, NZ) on the MAGPIX.

Unstimulated and antigen-stimulated peripheral blood mononuclear cells IFN- ?, IL-4 and IL-10 gene expression: A gene expression assay will be used to measure the expression of genes coding for IFN-y, IL-4 and IL-10 in peripheral blood mononuclear cells. Peripheral blood mononuclear cells (PBMC) will be isolated from the whole blood culture and total RNA will be extracted. PBMC RNA will be treated with DNase to remove contaminated genomic DNA.  Purified RNA will be reversed transcribed by a one-step real time PCR assay (Roche Light Cycler instruments (2.0 & 480)) to generate cDNA and specific PCR products for IFN-y, IL-4 and IL-10 genes. In addition to these genes, a reference gene will be used to normalize results.

Plasma cortisol: Plasma concentrations of cortisol will be measured using ELISA kits (DRG, Germany).

Blood glucose: Blood glucose will be measured using the COBAS analyser.

Substrate utilisation calculations: The application of indirect calorimetry (stoichiometry) will be used to estimate in vivo substrate utilisation (respiratory quotient (RQ)) from gaseous exchange measurements (respiratory exchange ratio (RER)). The stoichiometric equations (see below) originally published by Frayn and colleagues (1983), which assumes the contribution of protein is negligible, has been validated at exercise intensities up to 80-85% VO2max where a steady state has been achieved.

CHO oxidation (g/min) = 4.585 VCO2 – 3.226 VO2
Fat oxidation (g/min) = 1.695 VO2 – 1.701 VCO2
Intervention code [1] 297899 0
Prevention
Comparator / control treatment
Participants will act as their own control by consuming a placebo (i.e. drink containing no 1,3-butanediol) in a single-blinded randomised crossover design.
Control group
Placebo

Outcomes
Primary outcome [1] 301895 0
T-cell mediated immune response (i.e. peripheral blood T-cell subset count and balance, and stimulated cytokine production) using the Muse, RT-PCR, Magpix. T-cells will be stimulated using Staphylococcal enterotoxin B within a whole blood culture.
Timepoint [1] 301895 0
Baseline and 30, 120, 150 and 210 minutes after consumption of 1,3-butanediol (i.e. 30 min before exercise, immediately before exercise, immediately after sub maximal exercise, immediately after time-trial and 60 minutes after time trial).
Primary outcome [2] 303436 0
Salivary flow rate (i.e. volume of unstimulated saliva drool collected divided by collection time)
Timepoint [2] 303436 0
Baseline and 30, 150 and 210 minutes after consumption of 1,3-butanediol (i.e. 30 min before exercise, immediately before exercise, immediately after time-trial and 60 minutes after time trial).
Primary outcome [3] 303437 0
Salivary immunoglobulin A concentration and secretion rate (i.e. amount of salivary immunoglobulin A collected divided by collection time). sIgA will be measured an using in-house ELISA method.
Timepoint [3] 303437 0
Baseline and 30, 150 and 210 minutes after consumption of 1,3-butanediol (i.e. 30 min before exercise, immediately before exercise, immediately after time-trial and 60 minutes after time trial).
Secondary outcome [1] 334227 0
Pre-loaded time trial (time to complete the workload equivalent to 7kJ/kg following 85 minutes of cycling at 85% of the power output equivalent to their secondary ventilatory threshold).
Timepoint [1] 334227 0
Exercise completion
Secondary outcome [2] 338998 0
Tolerability (i.e. gastrointestinal and systemic symptoms)
Timepoint [2] 338998 0
Baseline and 30, 150 and 210 minutes after consumption of 1,3-butanediol (i.e. 30 min before exercise, immediately before exercise, immediately after time-trial and 60 minutes after time trial).
Secondary outcome [3] 338999 0
Lactate (capillary blood)
Timepoint [3] 338999 0
30, 120 and 150 minutes after consumption of 1,3-butanediol (i.e. immediately before exercise, immediately after submaximal exercise and immediately after time-trial).
Secondary outcome [4] 339000 0
Ketones (beta-hyroxybutyrate) and glucose (via finger capillary prick)
Timepoint [4] 339000 0
Baseline and 30, 60, 90, 120, 150 and 210 minutes after consumption of 1,3-butanediol (i.e. 30 min before exercise, immediately before exercise, 30 min during sub maximal exercise, 60 minutes during sub maximal exercise, immediately after submaximal exercise and, immediately after time trial and 1 hour after time trial)
Secondary outcome [5] 339001 0
Gaseous exchange analysis
Timepoint [5] 339001 0
Every twenty minutes during exercise for 3 minutes (no gas analysis will occur during the time trial).
Secondary outcome [6] 339002 0
Body weight and composition
Timepoint [6] 339002 0
Weight and skinfolds will be measured during the screening process. Weight will also be measured immediately pre and post exercise.
Secondary outcome [7] 339003 0
Adverse effects and safety
Timepoint [7] 339003 0
All adverse effects will either be communicated to the lead researcher via the tolerability questionnaire at designated time points or orally when symptoms arise. Participants will also be prompted following the completing of the sub maximal exercise and time trial to ascertain 'how they feel'. As previously described, all adverse effects and safety issues will immediately reported to the sports doctor.

Eligibility
Key inclusion criteria
Endurance-trained male cyclists; VO2peak >60mlkg/min; 18 – 35 years; history of competition; training for >2 years; train >6 hours per week; habitually consuming a mixed diet for at least 1 year; weight stable for >1 month.

Minimum age
18 Years
Maximum age
35 Years
Sex
Males
Can healthy volunteers participate?
Yes
Key exclusion criteria
Possess cardiovascular, metabolic, neurological, immunological or autoimmune disorders; baseline haematological values (leukocytes and erythrocyte counts) outside of normal range; experienced illness and/or upper respiratory symptoms within the previous 4 weeks; experienced GI symptoms within the previous 4 weeks or has a history of GI symptomology; consumed medications or supplements known to effect immunity within previous 2 weeks; smoker or previously smoked; family member has died before the age of 50 due to a heart condition.

Study design
Purpose of the study
Prevention
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Participants will be allocated to citrus flavoured drink containing either 0.7g/kg of 1,3-butanediol or placebo in a randomised order following their inclusion into the study. The primary researcher will not know the order of treatment for the participant during the participant screening process. Each trial will be allocated a number (i.e. 1 or 2). The day prior to the participant arriving, the investigator will generate a number (via random number generator) from 1 - 2 that will specify what drink will be used.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s


Intervention assignment
Crossover
Other design features
Nil
Phase
Phase 1
Type of endpoint/s
Safety/efficacy
Statistical methods / analysis
Descriptive statistics will be used to determine the centrality and spread of the data. The normality of each data set will be assessed prior to further statistical analysis. Datasets that defy the assumptions of normality will be log-transformed prior to analysis or analysed using non-parametric analysis. A Repeated Measures Anova will be used to identify whether within-group differences occurred. If significance is found, a paired t-test will be used to determine where the effect occurred. Differences between groups will be assessed using an unpaired t-test. Effects sizes will be determined using Cohen’s d effect size statistics; >0.2 (small), >0.5 (moderate) and >0.8 (large). Differences between group means will be analysed using an unpaired t-test. All analysis will be undertaken using the statistical package SPSS (Version 21, SPSS Inc., Chicago, IL), with significance accepted at P < 0.05. Below P = 0.01, P values will be reported as P < 0.01.

Data will be further analysed for clinical significance using magnitude-based inferences.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
12/10/2017
Actual
12/10/2017
Date of last participant enrolment
Anticipated
28/02/2018
Actual
28/02/2018
Date of last data collection
Anticipated
30/03/2018
Actual
30/03/2018
Sample size
Target
12
Accrual to date
Final
9
Recruitment outside Australia
Country [1] 8847 0
New Zealand
State/province [1] 8847 0
Auckland

Funding & Sponsors
Funding source category [1] 296292 0
University
Name [1] 296292 0
Auckland University of Technology
Country [1] 296292 0
New Zealand
Primary sponsor type
University
Name
Auckland University of Technology
Address
17 Antares Place, Rosedale, Auckland, 0632
Country
New Zealand
Secondary sponsor category [1] 295215 0
None
Name [1] 295215 0
Address [1] 295215 0
Country [1] 295215 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 297523 0
Northern B Health and Disability Ethics Committee
Ethics committee address [1] 297523 0
Ministry of Health 133 Molesworth Street, Wellington, 6011
Ethics committee country [1] 297523 0
New Zealand
Date submitted for ethics approval [1] 297523 0
24/02/2017
Approval date [1] 297523 0
21/04/2017
Ethics approval number [1] 297523 0
17/NTB/39

Summary
Brief summary
Athletes are constantly searching for novel dietary strategies to enhance performance and health. The use of 1,3-butanediol (1,3-BD), a dietary ketone precurser, has been suggested to influence endurance performance, with both positive and negative effects. The consumption of this ketone can increase blood ketone concentration to levels similar of a low carbohydrate, ketogenic diet, without the burden of drastic dietary change. The presence of ketones in the blood provides an additional energy source to muscle and the brain, and influences how the body uses its carbohydrate and fat stores. In some athlete circles, 1,3-BD is being used, however, its effects on immunity and tolerability (i.e. gastrointestinal and systemic symptoms) in male endurance athletes is not known. Considering endurance athletes are at a higher risk of illness and gastrointestinal distress, this study is important to provide an initial insight into the effect of 1,3-BD on these health markers. Local competitive, male cyclists, aged 18 - 35 will be recruited and will have to undertake a strenuous exercise protocol following the consumption of 1,3-butanediol (1,3-BD) (within a flavoured drink) or placebo in a randomised, crossover trial, with blood and saliva samples collected before and following exercise. These samples will be analysed for the defining immune markers of T-cell mediated immunity (blood) and mucosal immunity (saliva). providing a comprehensive depiction of the dynamic changes to the immune system.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 74318 0
Mr David Shaw
Address 74318 0
17 Antares Place, Second Level, Sports Performance Research Institute of NZ (SPRINZ), Rosedale, Auckland, 0632
Country 74318 0
New Zealand
Phone 74318 0
+64 21 0827 6137
Fax 74318 0
Email 74318 0
[email protected]
Contact person for public queries
Name 74319 0
David Shaw
Address 74319 0
17 Antares Place, Second Level, Sports Performance Research Institute of NZ (SPRINZ), Rosedale, Auckland, 0632
Country 74319 0
New Zealand
Phone 74319 0
+64 21 0827 6137
Fax 74319 0
Email 74319 0
[email protected]
Contact person for scientific queries
Name 74320 0
David Shaw
Address 74320 0
17 Antares Place, Second Level, Sports Performance Research Institute of NZ (SPRINZ), Rosedale, Auckland, 0632
Country 74320 0
New Zealand
Phone 74320 0
+64 21 0827 6137
Fax 74320 0
Email 74320 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
Individual participant data will not be made available to protect participant privacy.


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

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