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Trial registered on ANZCTR


Registration number
ACTRN12612001085864
Ethics application status
Approved
Date submitted
10/10/2012
Date registered
10/10/2012
Date last updated
21/01/2016
Type of registration
Prospectively registered

Titles & IDs
Public title
A vegetarian style diet versus a Western style diet on biomarkers of health and ageing in healthy volunteers
Scientific title
A pilot study investigating the effect and feasibility of a methionine restricted diet on biomarkers of health and ageing in healthy volunteers
Secondary ID [1] 281356 0
Nil
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Healthy volunteers 287577 0
Condition category
Condition code
Public Health 287902 287902 0 0
Health promotion/education
Diet and Nutrition 287924 287924 0 0
Other diet and nutrition disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Methionine restricted diet: As methionine content tends to be high in flesh foods, the methionine restricted diet will contain fewer meat options. The composition and energy intake of the methionine restricted diet will reflect that of the standard Western diet (~50% carbohydrate, ~15% protein and ~35% fat; 8400 KJ daily energy intake). To obtain a desirable amount of protein in the methionine restricted diet, foods that are higher in protein but lower in methionine will be chosen. For example, lentils contain roughly 25% more protein and less than half the methionine content per 100 g than beef. This study aims to restrict methionine as much as is practicable, approximately in the range of at least 40% but no more than 80% with a view to achieving 60% on average methionine restriction relative to the standard Western diet. This dietary intervention will run for 4 weeks. CSIRO will be providing a daily main meal during the intervention and guidelines for appropriate breakfast and lunch meals. There will be a 4 week washout between dietary interventions.
Intervention code [1] 285816 0
Lifestyle
Intervention code [2] 285838 0
Prevention
Comparator / control treatment
Standard Western diet: The standard Western diet is typically high in red meat, sugary desserts, high-fat foods, high-fat dairy products, sugary drinks and processed meat. In the current study, the standard Western diet will contain ~50% carbohydrate, ~15% protein and ~35% fat as is common with Western pattern diets. Energy intake will be targeted in the recommended range of 8400 KJ. This dietary intervention will run for 4 weeks. CSIRO will be providing a daily main meal during the intervention and guidelines for appropriate breakfast and lunch meals. There will be a 4 week washout between dietary interventions.
Control group
Active

Outcomes
Primary outcome [1] 288118 0
Plasma methionine measurement (blood sample assay).
Timepoint [1] 288118 0
Week 0, 2, 4, 8, 10, 12
Primary outcome [2] 288119 0
Oxidative Stress: ratio of reduced to oxidised glutathione and oxidised guanine in DNA (assay kit).
Timepoint [2] 288119 0
Week 0, 2, 4, 8, 10, 12
Primary outcome [3] 288120 0
Metabolic Stress as measured by mammalian target of rapamycin (mTOR) Activity (assay kit).
Timepoint [3] 288120 0
Week 0, 2, 4, 8, 10, 12
Secondary outcome [1] 299455 0
Serum inhibition of in vitro cancer cell culture growth as measured by Microculture Tetrazolium (MTT) assay.
Timepoint [1] 299455 0
Week 0, 2, 4, 8, 10, 12
Secondary outcome [2] 299456 0
Genome integrity of lymphocytes as determined by the cytokinesis-block micronucleus (CBMN) assay - frequency of chromosome breakage (micronuclei), chromosome loss (micronuclei), chromosome rearrangement, for example, dicentric chromosomes (nucleoplasmic bridges), gene amplification (nuclear buds), necrosis and apoptosis.
Timepoint [2] 299456 0
Week 0, 2, 4, 8, 10, 12

Eligibility
Key inclusion criteria
- Male or Female
- Aged 50-70
- Healthy with no history of cancer
- Body mass index in the healthy range (BMI): 18.5-27
Minimum age
50 Years
Maximum age
70 Years
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
- History of smoking
- Currently on medication/dietary supplements which may impact methionine, folate and B vitamin content in the blood
- Current vegetarians/vegans

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)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation by using a randomisation table created by computer software.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
Phase
Type of endpoint(s)
Statistical methods / analysis

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 286114 0
Self funded/Unfunded
Name [1] 286114 0
CSIRO
Address [1] 286114 0
Gate 13 Kintore Avenue
Adelaide, SA 5000
Country [1] 286114 0
Australia
Primary sponsor type
Government body
Name
CSIRO
Address
Gate 13 Kintore Avenue
Adelaide, SA 5000
Country
Australia
Secondary sponsor category [1] 284926 0
None
Name [1] 284926 0
Address [1] 284926 0
Country [1] 284926 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 288161 0
CSIRO Food and Nutritional Sciences Human Research Ethics Committee
Ethics committee address [1] 288161 0
Gate 13 Kintore Avenue
Adelaide, SA 5000
Ethics committee country [1] 288161 0
Australia
Date submitted for ethics approval [1] 288161 0
Approval date [1] 288161 0
27/08/2012
Ethics approval number [1] 288161 0
12/08/2012

Summary
Brief summary
The proposed project will investigate whether a methionine restricted diet is a feasible nutritional regimen for healthy ageing in a healthy population. This project will consist of 2 diets: a methionine restricted diet and a standard western diet. As methionine content tends to be higher in flesh foods, the methionine restricted diet will be predominantly plant based. The proposed project will utilise a randomised cross-over design so that each volunteer consumes both diets. Healthy volunteers (n=20) with no history of cancer will be recruited. The proposed project will measure the effect of a methionine restricted diet on biomarkers of health and ageing. Blood will be collected from the volunteers at specific time points and analysed for biomarkers of ageing; lymphocytes will be isolated to measure genome integrity and serum will be utilised in vitro to determine rate of growth of established cancer cell lines.
Trial website
Trial related presentations / publications
Oral Presentation:
Cavuoto P, Taylor P, May B, Weaver J, Lim Y, Zhou X, Fenech M. Methionine restriction as a healthy ageing strategy, is it safe and plausible in humans? Nugo Week 2015, 12th edition, Mechanisms of a Long-Life Health, Barcelona, Spain, September 7-9, 2015
Public notes

Contacts
Principal investigator
Name 34797 0
Dr Paul Cavuoto
Address 34797 0
CSIRO
Gate 13 Kintore Avenue
Adelaide, SA 5000
Country 34797 0
Australia
Phone 34797 0
+61 8 8303 8877
Fax 34797 0
Email 34797 0
paul.cavuoto@csiro.au
Contact person for public queries
Name 18044 0
Ms Julia Weaver
Address 18044 0
Gate 13 Kintore Avenue
Adelaide, SA 5000
Country 18044 0
Australia
Phone 18044 0
+61883038876
Fax 18044 0
Email 18044 0
julia.weaver@csiro.au
Contact person for scientific queries
Name 8972 0
Dr Paul Cavuoto
Address 8972 0
Gate 13 Kintore Avenue
Adelaide, SA 5000
Country 8972 0
Australia
Phone 8972 0
+61883038877
Fax 8972 0
Email 8972 0
paul.cavuoto@csiro.au

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary