Trial Review

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Trial registered on ANZCTR


Registration number
ACTRN12613001290785
Ethics application status
Approved
Date submitted
10/10/2013
Date registered
21/11/2013
Date last updated
20/07/2018
Type of registration
Prospectively registered

Titles & IDs
Public title
Dietary antioxidant intervention for reversal of airway inflammation and respiratory illness in athletes.
Scientific title
Dietary antioxidant intervention for reversal of airway inflammation and respiratory illness in athletes.
Secondary ID [1] 282752 0
Nil.
Universal Trial Number (UTN)
U1111-1145-2993
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Airway inflammation 289486 0
Respiratory illness 289487 0
Condition category
Condition code
Respiratory 289814 289814 0 0
Other respiratory disorders / diseases
Inflammatory and Immune System 290711 290711 0 0
Other inflammatory or immune system disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Two weeks following performing a VO2 max test to determine 90% VO2 max and after following a low antioxidant baseline diet (subjects will be provided with a diet protocol of foods to avoid), a sample group of moderately well-trained middle-distance and distance runners will follow a high-antioxidant diet for 14 days. After a two week washout the subjects will switch to the other diet. Using FoodWorks7, an analysis of antioxidant content of different fruits and vegetables has been conducted. Fruit and vegetable boxes will be designed to include fruits and vegetables with a high antioxidant content e.g. carrots, zucchinis, berries (>15,000ug). Participants will also be instructed to avoid other high antioxidant foods such as nuts, seeds, tea and wine. Fruit and vegetable boxes will be provided and a dietitian on hand if assistance with dietary prescription is required. Participants will be provided with a diet protocol specifying foods to avoid and ways to incorporate the fruits and vegetables provided, apart from this, subjects can consume any other foods. Participants will be instructed to consume 5 serves of vegetables and 2 serves of fruit/day. Diet will be monitored at the start and end of each 2 week period using a modified FFQ assessing fruit, vegetable and fat intake over the previous 2 weeks. Additionally, plasma carotenoids and tocopherols will be assessed. Impact on airway inflammation will be determined by measuring immunological markers, markers of anti-oxidant status and oxidative damage following a prescribed bout of treadmill running exercise (6x3mins intervals at 90% max with 90sec recovery).
Intervention code [1] 287470 0
Treatment: Other
Comparator / control treatment
Two weeks following performing a VO2 max test to determine 90% VO2 max and after following a low antioxidant baseline diet (subjects will be provided with a diet protocol of foods to avoid), a sample group of moderately well-trained middle-distance and distance runners will continue to follow a low-antioxidant diet for 14 days. After a two week washout the subjects will switch to the other diet. Using FoodWorks7, an analysis of antioxidant content of different fruits and vegetables has been conducted. Fruit and vegetable boxes will be designed to include low antioxidant content e.g. turnip, pear (<5000ug) fruits and vegetables. Participants will also be instructed to avoid high antioxidant foods such as other fruits and vegetables, nuts, seeds, tea and wine. Fruit and vegetable boxes will be provided and a dietitian on hand if assistance with dietary prescription is required. Participants will be provided with a diet protocol specifying foods to avoid and ways to incorporate the fruits and vegetables provided, apart from this, subjects can consume any other foods. Participants will be instructed to consume 5 serves of vegetables and 2 serves of fruit/day. Diet will be monitored at the start and end of each 2 week period using a modified FFQ assessing fruit, vegetable and fat intake over the previous 2 weeks. Additionally, plasma carotenoids and tocopherols will be assessed. Impact on airway inflammation will be determined by measuring immunological markers, markers of anti-oxidant status and oxidative damage following a prescribed bout of treadmill running exercise (6x3mins intervals at 90% max with 90sec recovery).
Control group
Active

Outcomes
Primary outcome [1] 289944 0
Eosinophilic airway inflammation will be determined by fractional exhaled nitric oxide.
Timepoint [1] 289944 0
Baseline, 2, 4 and 6 weeks
Secondary outcome [1] 303627 0
Respiratory symptoms will be assessed using a symptom and illness log developed validated by the Australian Institute of sport. This questionnaire has been previously approved by the University of Newcastle ethics committee (H-2012-0121) and is also available online.
Timepoint [1] 303627 0
Baseline, 2, 4 and 6 weeks
Secondary outcome [2] 305650 0
Systemic Inflammation and oxidative stress will be determined from laboratory analysis of collected blood samples. Biomarkers of inflammation will include IL-6, IL-10 and CRP and of oxidative stress will include thiobarbituric acid reactive substances (TBARS).
Timepoint [2] 305650 0
Weeks 0, 2, 4 & 6

Eligibility
Key inclusion criteria
Subjects must have trained regularly (at least 5 times per week ~>40 km running.wk-1) for at least 1 year, and a treadmill V02 >45 ml.kg-1.min-1.
Minimum age
18 Years
Maximum age
45 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Any diagnosed health condition affecting respiratory and immune function e.g. asthma

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
Phase
Type of endpoint/s
Efficacy
Statistical methods / analysis
Descriptive statistics (mean and SD) and magnitude-based inferences will be used to characterise the inflammatory response to the exercise trials. The mean effect of treatments on inflammatory markers will be estimated via the unequal-variances t statistic computed for the difference in the change in the mean scores between pre- and post-tests. Each subject's change score will be expressed as a percentage of baseline score via analysis of log-transformed values, in order to reduce bias arising from non-uniformity of error. The magnitude of difference between treatments will be expressed as a standardised effect size. The criteria to interpret the magnitude of the sizes are: <0.2 trivial, 0.2-0.6 small, 0.6-1.2 moderate, 1.2-2.0 large and > 2.0 very large. The precision of these estimates will be indicated by 90% confidence limits. An effect will be inferred to be unclear if its confidence interval spanned substantial positive and substantial negative values (+/- 0.2 of the between-subject standard deviation). As this study is being conducted to inform sporting organisations and generally sporting teams have small numbers, this number of participants was selected by an experienced researcher in the field and was selected so that if results show significance researchers can be more confident that this can be translated into practice. Also this study is somewhat exploratory to determine if this is an area warranting further investigation so there is a possibility for a larger study to be conducted in the future if results look promising.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
2/12/2013
Actual
25/03/2014
Date of last participant enrolment
Anticipated
Actual
2/02/2015
Date of last data collection
Anticipated
Actual
2/04/2015
Sample size
Target
16
Accrual to date
Final
17
Recruitment in Australia
Recruitment state(s)
NSW

Funding & Sponsors
Funding source category [1] 287560 0
Government body
Name [1] 287560 0
Australian Sports Commission
Country [1] 287560 0
Australia
Primary sponsor type
University
Name
University of Newcastle
Address
University Drive,
Callaghan NSW 2308
Country
Australia
Secondary sponsor category [1] 286311 0
None
Name [1] 286311 0
Address [1] 286311 0
Country [1] 286311 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 289537 0
University of Newcastle Human Research Ethics Committee
Ethics committee address [1] 289537 0
University Drive, Callaghan NSW 2308
Ethics committee country [1] 289537 0
Australia
Date submitted for ethics approval [1] 289537 0
06/09/2013
Approval date [1] 289537 0
11/10/2013
Ethics approval number [1] 289537 0
H-2013_0315

Summary
Brief summary
To compare the relative effectiveness of short-term 14 day high and low-antioxidant diet on airway inflammation, respiratory symptoms and immune function in athletes.
Trial website
Trial related presentations / publications
None
Public notes

Contacts
Principal investigator
Name 41094 0
A/Prof Lisa Wood
Address 41094 0
Level 2 West, Hunter Medical Research Institute, Kookaburra Circuit, New Lambton Heights, NSW, 2305
Country 41094 0
Australia
Phone 41094 0
+61 2 4042 0147
Fax 41094 0
Email 41094 0
[email protected]
Contact person for public queries
Name 41095 0
Miss Rebecca Williams
Address 41095 0
Level 2 West, Hunter Medical Research Institute, Kookaburra Circuit, New Lambton Heights, NSW, 2305
Country 41095 0
Australia
Phone 41095 0
+61 2 4042 0139
Fax 41095 0
Email 41095 0
[email protected]
Contact person for scientific queries
Name 41096 0
Miss Rebecca Williams
Address 41096 0
Level 2 West, Hunter Medical Research Institute, Kookaburra Circuit, New Lambton Heights, NSW, 2305
Country 41096 0
Australia
Phone 41096 0
+61 2 4042 0139
Fax 41096 0
Email 41096 0
[email protected]

No information has been provided regarding IPD availability


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.