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Trial registered on ANZCTR


Registration number
ACTRN12617000205336
Ethics application status
Approved
Date submitted
6/02/2017
Date registered
8/02/2017
Date last updated
12/06/2018
Type of registration
Retrospectively registered

Titles & IDs
Public title
Can an increase in consumption of dietary fibre improve gut flora profile, bowel habit and sense of wellbeing in healthy adults?
Scientific title
Comparing the effects of diets low and moderate in natural prebiotic fibre on gut flora profile, laxation and sense of wellbeing in healthy Australian adults.
Secondary ID [1] 290865 0
CF14/2904- 2014001593
Secondary ID [2] 290866 0
D.MHN.0617
Universal Trial Number (UTN)
Trial acronym
Linked study record
Details of pilot study have not been published

Health condition
Health condition(s) or problem(s) studied:
gut health 301562 0
sense of wellbeing 301563 0
Condition category
Condition code
Diet and Nutrition 301275 301275 0 0
Other diet and nutrition disorders
Oral and Gastrointestinal 301276 301276 0 0
Normal oral and gastrointestinal development and function
Mental Health 301277 301277 0 0
Studies of normal psychology, cognitive function and behaviour

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
25 healthy volunteers (no pre-existing gastrointestinal disorders) will be recruited into a single-blinded, randomised, cross-over design study of 12 weeks in duration. They will each follow the following three dietary treatments for 3 weeks with a 1 week break between each treatment and 1 week baseline period prior to commencing the first study diet . The three treatments will be consistent with the Australian Dietary Guidelines in terms of recommended foods and serves of foods and will differ only in relation to the types of carbohydrate containing foods (including grains, legumes, fruits and vegetables) provided to modify intake of naturally occurring indigestible oligosaccharides (which have known prebiotic effects), in the following amounts:

1. Low prebiotic diet (~4g oligosaccharides/day)
2. Moderate prebiotic diet (~8g oligosaccharides/day)
3. High prebiotic diet (~12g oligosaccharides/day)

The majority of food will be provided to participants for this study and will be prepared in Monash University's commercial kitchen by their research chef. Menu planning will include beef and lamb as recommended in the 'Australian Dietary Guidelines' i.e. 130g every second day (200g uncooked meat).

Sample study meal plan for one day:
Low prebiotic diet-
Breakfast: Cereal (flakes of corn, puffed oats, puffed rice, rice bran, dried cranberries, almonds, sunflower seeds) with milk + tea and/or coffee + orange juice + yoghurt.
Snack: Banana
Lunch: Sourdough spelt bread sandwich with ham, cheese and salad + tea and/or coffee + yoghurt with strawberries
Snack: Mix of macadamia, Brazil nuts and pecans
Dinner: Beef curry (with small amount of onion and garlic) served with rice, vegetables and pita bread.

Moderate prebiotic diet-
Breakfast: Cereal (flakes of wheat, rolled oats, dried apple, wheat bran, cashews, sunflower seeds) with milk + tea and/or coffee + apple juice + yoghurt.
Snack: Nectarine
Lunch: Wholemeal bread sandwich with ham, cheese and salad (including beetroot) + tea and/or coffee + yoghurt with peaches
Snack: Mix of cashew nuts and almonds
Dinner: Beef curry (with moderate amounts of onion and garlic) served with lentil curry, rice, vegetables and pita bread.

High prebiotic diet-
Breakfast: Cereal (flakes of amaranth, lupin flakes, wheat bran, dried mango, pistachio nuts) with milk + tea and/or coffee + apple juice + yoghurt.
Snack: Watermelon
Lunch: Rye bread sandwich with ham, cheese and salad (including beetroot and asparagus) + tea and/or coffee + yoghurt with mango
Snack: Mix of cashew and pistachio nuts
Dinner: Beef curry (with large amounts of onion and garlic) served with lentil curry, rice, vegetables and naan bread.

Evaluation of dietary adherence:
This will be checked via direct questioning, via daily diaries into which any food consumed in addition to that supplied will be entered and via assessment of uneaten food.
Breath hydrogen/methane testing will also evaluate adherence. Hourly breath samples for hydrogen and methane testing will be collected over a one-day period to assess the degree of fermentation occurring with each diet.



Intervention code [1] 296813 0
Treatment: Other
Intervention code [2] 297091 0
Lifestyle
Comparator / control treatment
As this is a cross-over study design, participants act as their own control.
Control group
Active

Outcomes
Primary outcome [1] 300688 0
Detection and characterisation of gut microbial changes as reflected in collected faecal samples. Analysis will include use of real-time PCR to compare the absolute and relative abundance of bacteria.

Timepoint [1] 300688 0
Faecal samples collected on three consecutive days during the baseline week and three consecutive days during the third week of each dietary intervention period. In addition, an aliquot from one faecal sample will be taken by participants on the second (or third) day of each faecal collection period using a sampling kit containing a specialised microbial preservative.
Primary outcome [2] 300689 0
Changes in regional gut transit time and luminal pH from mouth to anus measured using a SmartPill device.
Timepoint [2] 300689 0
Device swallowed on the last day of the second week (day 14) of each dietary intervention period.
Secondary outcome [1] 330610 0
Changes in faecal water content measured by weighing faecal sample before and after freeze-drying.
Timepoint [1] 330610 0
Faecal samples collected on three consecutive days during the baseline week and three consecutive days during the third week of each dietary intervention period.
Secondary outcome [2] 330611 0
Changes in faecal levels of short chain fatty acids, including butyrate measured using gas-liquid chromatography.
Timepoint [2] 330611 0
Faecal samples collected on three consecutive days during the baseline week and three consecutive days during the third week of each dietary intervention period.
Secondary outcome [3] 330612 0
Changes in levels of faecal ammonia and phenols measured by high-performance liquid chromatography.
Timepoint [3] 330612 0
Faecal samples collected on three consecutive days during the baseline week and three consecutive days during the third week of each dietary intervention period.
Secondary outcome [4] 330613 0
Changes in faecal calprotectin concentration measured by commercially available ELISA (Buhlman) as a quantitative marker of intestinal inflammation.
Timepoint [4] 330613 0
Faecal samples collected on three consecutive days during the baseline week and three consecutive days during the third week of each dietary intervention period.
Secondary outcome [5] 330614 0
Changes in gastrointestinal symptoms (including bloating, wind, abdominal pain and fatigue) assessed using a 100mm visual analogue scale.
Timepoint [5] 330614 0
Daily throughout the baseline and dietary intervention periods.
Secondary outcome [6] 330615 0
Changes in stool frequency/consistency assessed using the Bristol stool chart and recorded on a 4-point (frequency) and 7-point (consistency) likert scale.
Timepoint [6] 330615 0
Daily during baseline and dietary intervention periods.
Secondary outcome [7] 330616 0
Changes in breath hydrogen and methane levels as assessed using a QuinTron breath track Analyser instrument.
Timepoint [7] 330616 0
Samples collected during one 12-hour testing period on the second last day of the second week (day 13) of each dietary intervention period.
Secondary outcome [8] 330617 0
Changes in cognitive function assessed by Subtle Cognitive Impairment Test (SCIT).
Timepoint [8] 330617 0
On final day of each dietary intervention period.
Secondary outcome [9] 330618 0
Changes in psychological state assessed using the 80 item State-Trait-Personality Inventory (STPI) and 21 item Depression Anxiety Stress Scale (DASS 21).
Timepoint [9] 330618 0
On final day of baseline and each dietary intervention period.
Secondary outcome [10] 330619 0
Changes in levels of fatigue measured using the 40 item Daily Fatigue Impact Scale (D-FIS).
Timepoint [10] 330619 0
On final day of baseline and dietary intervention periods.

Eligibility
Key inclusion criteria
- Generally healthy adults with no pre-existing gastrointestinal conditions (e.g. Irritable bowel syndrome, coeliac disease, Crohn's disease or Ulcerative colitis)
Minimum age
18 Years
Maximum age
65 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
- Currently or recently (last 4 weeks) been taking antibiotics, probiotics or prebiotics as supplements or added into food types
- Being treated with medication known to affect intestinal transit (such as laxatives or hypomotility agents)
- They have any gastrointestinal disease (e.g. Irritable bowel syndrome, coeliac disease, Crohn's disease or Ulcerative colitis)
- They suffer from an eating disorder
- Are pregnant or planning a pregnancy
- Vegetarian

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)
Central randomisation by computer
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s


Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
The power calculations for this study were based on the smallest effect size of bacterial abundance (R. torques) and the most conservative statistical procedures that could be used: a linear mixed model analysis for crossover designs with one repeated measure. The alpha (or p) value is set at at 0.001 to allow for Bonferroni corrections for multiple comparisons. On the basis of linear mixed model analysis for crossover designs, with an alpha level of 0.001, a desired power level of 0.95 and a Cohen's d effect size measure of 1.095, the minimum sample required to complete this study is 24. Assuming a drop-out rate of around 20% this means that ~ 29 people will need to be recruited.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
12/02/2015
Date of last participant enrolment
Anticipated
31/10/2017
Actual
9/01/2018
Date of last data collection
Anticipated
31/12/2017
Actual
24/04/2018
Sample size
Target
40
Accrual to date
Final
34
Recruitment in Australia
Recruitment state(s)
VIC
Recruitment postcode(s) [1] 15007 0
3004 - St Kilda Road Melbourne

Funding & Sponsors
Funding source category [1] 295297 0
Commercial sector/Industry
Name [1] 295297 0
Meat & Livestock Australia Limited
Country [1] 295297 0
Australia
Primary sponsor type
University
Name
Monash University
Address
Wellington Road
Clayton, VIC
3800
Country
Australia
Secondary sponsor category [1] 294117 0
None
Name [1] 294117 0
Address [1] 294117 0
Country [1] 294117 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 296630 0
Monash University Human Research Ethics Committee
Ethics committee address [1] 296630 0
Monash University
Wellington Road,
Clayton, VIC
3800
Ethics committee country [1] 296630 0
Australia
Date submitted for ethics approval [1] 296630 0
30/09/2014
Approval date [1] 296630 0
26/11/2014
Ethics approval number [1] 296630 0
CF14/2904- 2014001593

Summary
Brief summary
This project aims to discover new understanding regarding whether an increase in dietary fibre will improve the profile of gut flora (i.e., the micro-organisms that aid digestion), bowel habit and sense of wellbeing. There is strong evidence suggesting dietary fibre is essential for good health. This project aims to understand better the fibre-health relationship.
Trial website
Trial related presentations / publications
Public notes
Note: A pilot of this study was conducted in 9 participants using the aforementioned protocol. Due to participants experiencing uncomfortable gastrointestinal side effects on the high prebiotic (~12g/day) diet, this study arm was discontinued and a 2-arm version of the trial continued with only the low and moderate prebiotic dietary interventions. All other aspects of the protocol remained unchanged, however the study length was subsequently reduced from 12 to to 8 weeks in duration.

Contacts
Principal investigator
Name 71554 0
Dr Jane Muir
Address 71554 0
Monash University Department of Gastroenterology
Level 6, The Alfred centre
99 Commercial Rd
Melbourne, VIC
3004
Country 71554 0
Australia
Phone 71554 0
+610399030274
Fax 71554 0
Email 71554 0
[email protected]
Contact person for public queries
Name 71555 0
Lyndal McNamara
Address 71555 0
Monash University Department of Gastroenterology
Level 6, The Alfred centre
99 Commercial Rd
Melbourne, VIC
3004
Country 71555 0
Australia
Phone 71555 0
+610399030269
Fax 71555 0
Email 71555 0
[email protected]
Contact person for scientific queries
Name 71556 0
Jane Muir
Address 71556 0
Monash University Department of Gastroenterology
Level 6, The Alfred centre
99 Commercial Rd
Melbourne, VIC
3004
Country 71556 0
Australia
Phone 71556 0
+610399030274
Fax 71556 0
Email 71556 0
[email protected]

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