An investigation into whether the way potato is prepared, and what it is eaten with, affects the blood glucose response to its consumption, in people with type 2 diabetes

ISRCTN ISRCTN67897032
DOI https://doi.org/10.1186/ISRCTN67897032
IRAS number 291203
Secondary identifying numbers CPMS 49430, IRAS 291203
Submission date
26/07/2021
Registration date
12/08/2021
Last edited
29/05/2024
Recruitment status
No longer recruiting
Overall study status
Completed
Condition category
Nutritional, Metabolic, Endocrine
Prospectively registered
Protocol
Statistical analysis plan
Results
Individual participant data
Record updated in last year

Plain English summary of protocol

Background and study aims
There is existing data that demonstrates that the way potato is prepared and cooked affects the blood glucose response to its consumption, but none of this work has been undertaken in type 2 diabetes (T2D). It has been argued that work in healthy individuals can simply be “translated directly” into other patient groups, however, the blood glucose response to a food is affected by insulin sensitivity, gastrointestinal motility, gut hormone response and the absorption rate of glucose. All of these factors are likely to be different in T2D. Typically potatoes are not eaten in isolation but as part of mixed meals containing both fat and protein which can also affect the glucose response. This study aims to investigate not just the glucose response to different potato preparations eaten in normal quantities, but also in normal food patterns, in a group of people with type 2 diabetes.

Who can participate?
Males and females, aged 18-70 years, with a diagnosis of type 2 diabetes longer than 6 months.

What does the study involve?
Participants will be required to attend 12 study sessions. Each session will involve eating a potato-based meal and providing finger-prick blood samples for the next 3 hours (9 samples per visit). Each visit will be separated by at least two days.

What are the possible benefits and risks of participating?
The main benefit to the participant is that they will be provided with their own personal results at the end of the study, so they can see how their own blood glucose response varies with the different cooking methods. This will allow them to amend their own cooking practises at home in order to better control their blood glucose. There is a risk of slight bruising and discomfort to the fingertips, due to the sampling method, however this usually resolves within a day and can be minimised by correct sampling technique.

Where is the study run from?
University of Surrey (UK)

When is the study starting and how long is it expected to run for?
August 2019 to October 2022

Who is funding the study?
The Alliance for Potato Research and Education (APRE) (USA)

Who is the main contact?
Dr Tracey Robertson - Email: t.m.robertson@surrey.ac.uk

Contact information

Dr Tracey Robertson
Scientific

Department of Nutritional Sciences
University of Surrey
Leggett Building
Daphne Jackson Rd
Guildford
GU2 7WG
United Kingdom

ORCiD logoORCID ID 0000-0002-8519-7572
Phone +44 (0)1483 688609
Email t.m.robertson@surrey.ac.uk

Study information

Study designNon-randomized; Interventional; Design type: Prevention, Dietary
Primary study designInterventional
Secondary study designRandomised controlled trial
Study setting(s)Other
Study typeTreatment
Participant information sheet Not available in web format, please use the contact details to request a patient information sheet.
Scientific titleThe effect of potato form and consumption pattern on acute glycaemia in individuals with type 2 diabetes
Study objectives1. The way potato is prepared will affect the blood glucose response to its consumption
2. The addition of protein and fat to potato prepared in different ways, will reduce both the overall blood glucose response and any differences between different potato preparations in comparison to the identical potato meals consumed in isolation
Ethics approval(s)Approved 18/06/2021, London Bridge Research Ethics Committee (LHREC) (Skipton House, 80 London Road, Health Research Agency, SE1 6LH, UK; +44 (0) 207104 8202; londonbridge.rec@hra.nhs.uk), ref: 21/PR/0672
Health condition(s) or problem(s) studiedType 2 diabetes
InterventionThe study will be a randomised crossover study consisting of 12 study visits per participant.

Each study visit will last approximately 4 hours. Participants will arrive in the morning after an overnight fast. They will provide a finger-prick blood sample then consume the study meal. They will continue to provide finger-prick blood samples at regular intervals for the next 3 hrs. There are 6 different study meals; each participant will consume each meal twice over the course of their 12 study mornings. Each study visit will be separated by at least 2 days.
Intervention typeOther
Primary outcome measureAt each visit using blood test:
1. Incremental area under the 3 h glucose response curve (IAUC). Sample timepoints are 0, 15, 30, 45, 60, 75, 90, 120 and 180 min.
Secondary outcome measuresAt each visit using blood test:
1. Incremental area under the 3 h insulin response curve (IAUC). Sample timepoints are 0, 15, 30, 45, 60, 75, 90, 120 and 180 min.
2. Peak glucose.
3. Peak insulin.
4. Time-to-peak glucose.
5. Time-to-peak insulin.
6. Matsuda Index.
7. Insulinogenic index.
Overall study start date16/08/2019
Completion date11/10/2022

Eligibility

Participant type(s)Patient
Age groupAdult
Lower age limit18 Years
Upper age limit70 Years
SexBoth
Target number of participantsPlanned Sample Size: 12; UK Sample Size: 12
Total final enrolment12
Key inclusion criteria1. Patients with a diagnosis of type 2 diabetes >6 months
2. Males and females
3. Aged 18-70 years
4. Ability to understand English (to provide informed consent)
Key exclusion criteria1. Use of insulin and GLP-1 analogues
2. History of gastroparesis or gastric surgery
3. Coeliac disease/wheat intolerance
4. Irritable bowel syndrome
5. HbA1c >75 mmol/mol
6. Pregnancy/breastfeeding
7. Excess alcohol intake
8. Glucose-lowering drug dosage adjustment within the previous month
9. Antibiotics in the last 3 months
Date of first enrolment01/08/2021
Date of final enrolment30/04/2022

Locations

Countries of recruitment

  • England
  • United Kingdom

Study participating centre

University of Surrey
Clinical Investigation Unit (CIU)
Guildford
GU2 7XH
United Kingdom

Sponsor information

University of Surrey
University/education

RIGO, 4th Floor Senate House
Guildford
GU2 7XH
England
United Kingdom

Phone +44 (0)1483 683499
Email rigo@surrey.ac.uk
Website http://www.surrey.ac.uk/
ROR logo "ROR" https://ror.org/00ks66431

Funders

Funder type

Research organisation

Alliance for Potato Research & Education

No information available

Results and Publications

Intention to publish date31/10/2024
Individual participant data (IPD) Intention to shareNo
IPD sharing plan summaryData sharing statement to be made available at a later date
Publication and dissemination planPlanned publication in a high-impact peer-reviewed journal.
IPD sharing planThe current data sharing plans for this study are unknown and will be available at a later date.

Study outputs

Output type Details Date created Date added Peer reviewed? Patient-facing?
HRA research summary 28/06/2023 No No

Editorial Notes

29/05/2024: The intention to publish date was changed from 01/04/2024 to 31/10/2024.
16/11/2023: The intention to publish date was changed from 01/10/2023 to 01/04/2024.
11/10/2022: The following changes were made to the trial record:
1. The overall end date was changed from 01/09/2022 to 11/10/2022.
2. The total final enrolment was added.
3. The plain English summary was updated to reflect these changes.
26/07/2021: Trial's existence confirmed by the NIHR.