PrehypertensionMI-DIETNCT04326686
Measuring Individual Responses to a Wholegrains and Nuts Intervention to Reduce Blood Pressure in Prehypertension
A study testing Dietary intervention: nuts and wholegrains with dietary advice for a blood-pressure lowering diet in people with Prehypertension, run by University of Aberdeen at 1 site in United Kingdom.
Trial summary
The aim of the study is to investigate whether physiological, psychological and environmental factors, at an individual level, modify a) adherence, and b) blood pressure response, to a nuts and wholegrains intervention in participants at risk for developing high blood pressure. Read more about this study
- Who is it for?
- Ages 18 to 75 yearsHealthy volunteers can take part
- Conditions the study is for
- Prehypertension
- What is being tested?
- Dietary intervention: nuts and wholegrains with dietary advice for a blood-pressure lowering diet
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 12 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 30 Oct 2020to 25 Mar 2022
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 75 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Mildly elevated blood pressure levels: systolic blood pressure (SBP) >120 <=140mmHg and/or diastolic blood pressure (DBP) >80 <=90mmHg.
- Low habitual intake of wholegrains: <=7 portions/week
- Body Mass Index (BMI) between 18-35
- Possessing a smartphone capable of running the Qardio app in conjunction with the QardioArm wireless blood pressure monitor
Who cannot join
- SBP <120 or >140mmHg or DBP <80 or >90mmHg. Participants with SBP > 140 or DBP > 90 will be advised to visit their GP to have their blood pressure reassessed in a clinical setting.
- Diagnosed with diabetes
- Clinically diagnosed with hypertension or hypercholesterolemia
- Unstable or untreated thyroid disorder
- Taking blood pressure- or cholesterol-lowering medications (e.g. beta blockers or statins)
- Following a low carbohydrate/gluten free diet
Show all 13Show fewer
- Coeliac disease/gluten insensitivity
- Any food allergies
- Being on a weight loss diet or having lost >5kg in the last 6 months
- Any history of an eating disorder
- >7 portions/week habitual wholegrains consumption
- Having taken part in a study where wholegrains were provided in the last 3 months
- Not possessing a smartphone to run the Qardio app.
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
The Rowett Institute, University of Aberdeen
Aberdeen, Aberdeen City, AB25 2ZD
About this study
Official title: Examining Factors Influencing Adherence to and Efficacy of a Wholegrains and Nuts Intervention to Reduce Blood Pressure in Prehypertension: a Series of N-of-1 Interventional Studies
The aim of the study is to investigate whether physiological, psychological and environmental factors, at an individual level, modify a) adherence, and b) blood pressure response, to a nuts and wholegrains intervention in participants at risk for developing high blood pressure. For 24 weeks, participants will, on a daily basis, monitor their own blood pressure using a wireless blood pressure monitor and respond to short semi-personalised questionnaires using a wrist-worn device, which also measures activity levels. Participants will receive an intervention of wholegrain foods and nuts to substitute into their diets for 8 weeks, between two 8-week observation periods. The length of the study periods will enable repeated measurements to be taken, in order to assess what factors, on an individual level, are associated with fluctuations in the outcomes. This will provide an insight into the types of factors that can help to explain individual fluctuations in adherence and physiological outcomes, such as blood pressure, that are common in nutrition studies. In the future, this should help in tailoring the way the investigators deliver effective individualised interventions, and enable researchers to be better able to consider and control for factors that can affect adherence and response to dietary interventions.
Read the detailed description
The study will be conducted as an interventional N-of-1 study with an A1-B-A2 design of 8 weeks per study period. Prior to the study, participants will be screened and if eligible, will complete a number of baseline questionnaires to provide an overview of their typical eating and lifestyle-related behaviours, and general health. A second visit prior to the start of the study will then be arranged, where participants will undergo a semi-structured interview. Responses from the interview, in combination with their baseline questionnaire responses, will be used to identify factors specific to the participant that show some degree of variability. These will form the basis of the semi-personalised questionnaires delivered via the wrist-worn PRO-Diary device for the duration of the study. During the study, participants will visit the institute in a fasted state every 4 weeks (7 visits total), in order to provide a blood sample for assessment of cholesterol levels and for assessment of biomarkers of wholegrains intake. At the first visit, participants will receive the wireless blood pressure monitor and PRO-Diary wrist device programmed with twice-daily questionnaires at times convenient to the participant. After 2 weeks and every 4 weeks thereafter, participants will be sent a link by email to complete a 24-hour dietary recall. After 8 weeks, participants will begin the intervention phase and receive wholegrains equivalent to 3 portions a day and 1 portion of unsalted nuts per day for the following 8 weeks. Participants will be able to choose from a variety of wholegrain products commonly available at supermarkets. They will also receive dietary advice to follow a Dietary Approaches to Stop Hypertension (DASH) diet aimed at lowering blood pressure. All other measures will continue as previously. At week 16, the wholegrains and nuts will be withdrawn and participants will be followed up for a further 8 weeks. At their final visit to the institute, they will complete the same validated questionnaires as at baseline. Results from the study will be analysed using N-of-1 dynamic modelling to analyse trends over time and determine whether any personalised factors significantly affected adherence to intervention or blood pressure response.
- Conditions
- Prehypertension
- Being tested
- Dietary intervention: nuts and wholegrains with dietary advice for a blood-pressure lowering diet
- Keywords
- N-of-1, Ecological Momentary Assessment, Blood pressure, Whole grains, Nuts
- Medical subject headings
- Prehypertension
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Dietary intervention: nuts and wholegrains with dietary advice for a blood-pressure lowering dietOther
30g mixed unsalted tree nuts (almonds, hazelnuts and almonds) per day; 3 portions of wholegrain foods per day (including wholegrain cereal products, wholegrain bread and wholegrain pasta); guidance for following the Dietary Approaches to Stop Hypertension (DASH) diet
| Study group | Role | What they receive |
|---|---|---|
| N-of-1 study | Other | For 24 weeks, each participant will measure their blood pressure and respond to questionnaires daily, and visit the institute to provide a blood sample every 4 weeks. The study is split into three 8-week phases, the first of which will start when each participant is enrolled. For the first 8-week observation phase (A1) the participant is instructed to continue with their usual diet and exercise habits. For the second 8-week intervention phase (B), the participant will be provided with wholegrains and nuts and recommended to substitute these in place of refined grains and other snacks, respectively. They will also receive dietary advice for following the Dietary Approaches to Stop Hypertension (DASH) diet. For the final 8 week follow-up period (A2), provision of wholegrains and nuts will cease but the participant will continue with measurements at the same frequency as previously. Receives: Other: Dietary intervention: nuts and wholegrains with dietary advice for a blood-pressure lowering diet |
What is being measured
The primary outcome is the main question the study is designed to answer.
Adherence to wholegrains and nuts consumption
Number of portions of wholegrains consumed and whether a portion of nuts were consumed, reported daily via the PRO-Diary wrist device.
Measured: 8-week intervention period
Change in plasma alkylresorcinol levels reflecting wholegrains intake
Concentration of alkylresorcinols as a measure of wholegrains intake in nmol/L
Measured: Every 4 weeks from start of study up to 24 weeks
Change in blood pressure
Blood pressure (both systolic and diastolic) will be taken daily by participants via the QardioArm wireless blood pressure monitor. 3 measurements are taken automatically and averaged.
Measured: From start of study up to 24 weeks
Secondary outcomes (4)
Correlation between adherence and blood pressure change
Correlation between adherence and blood pressure change will be examined using N-of-1 dynamic modelling. Daily blood pressure measurements and PRO-Diary questionnaire responses will be provided during the whole study. Questionnaire responses will be given on a Visual Analogue Scale from 0-100.
Measured: 8-week intervention period
Total, LDL and HDL cholesterol levels
Fasted blood samples will be taken to determine whether wholegrains and nuts consumption has an effect on blood cholesterol levels.
Measured: 4-week blood samples
Amount of wholegrains and nuts consumed during follow-up reported using PRO-Diary questionnaires
For the final 8 weeks of the study, provision of wholegrains and nuts will cease but participants will continue to be asked about their consumption of these products through daily PRO-Diary questionnaires. This is to determine if habit formation has occurred and led to continuation of consumption of these products
Measured: 8-week follow-up phase
Determination of personal factors which correlate with study outcomes using Ecological Momentary Assessment (EMA) through the PRO-Diary device
Participants will respond to semi-personalised questionnaires daily using a Visual Analogue Scale from 0-100 using the PRO-Diary device. The PRO-Diary will also track movement collected during 60-second epochs via accelerometry. The influence of these factors on the primary and secondary outcomes above will be aggregated using N-of-1 dynamic modelling. Due to the semi-personalised nature of the questionnaires, the exact predictors examined in each N-of-1 study will differ. Analysis of each N-of-1 study will be conducted separately.
Measured: 24 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Mar 2020
- Study start30 Oct 2020
- Primary completion25 Mar 2022
- Study completion25 Mar 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for PrehypertensionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- This is a series of N-of-1 studies where data from each participant will be analysed separately. Each study follows an A1-B-A2 design consisting of an initial observation phase, an intervention phase and a follow-up phase, each of 8 weeks duration.
- Masking
- None (open label)
- Enrolment
- 12 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Aberdeen
- Sponsor type
- University, hospital or other
- Collaborators
- Biotechnology and Biological Sciences Research Council, Unilever R&D
- Responsible party
- Sponsor
- Investigators
- Baukje de Roos, Principal investigator, The Rowett Institute, University of Aberdeen
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04326686
- Sponsor's protocol ID
- MI-DIET
- Acronym
- MI-DIET
- Status last verified
- May 2022
- First submitted
- 20 Mar 2020
- Last updated
- 17 May 2022
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Potter TIT, Pepping F, Wanders AJ, Zandstra EH, Zock PL, Landberg R, Vieira R, de Roos B. A series of N-of-1 dietary intervention studies with whole-grain foods and nuts reveals individual predictors of blood pressure and heart rate. Eur J Clin Nutr. 2026 Aug;80(8):799-813. doi: 10.1038/s41430-026-01740-3. Epub 2026 Apr 28.
PubMed 42049896
Study at a glance
From the registry record, last updated by the sponsor on 17 May 2022. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Examining Factors Influencing Adherence to and Efficacy of a Wholegrains and Nuts Intervention to Reduce Blood Pressure in Prehypertension: a Series of N-of-1 Interventional Studies
- ClinicalTrials.gov ID
- NCT04326686
- Acronym / sponsor ID
- MI-DIET / MI-DIET
- Conditions
- Prehypertension
- Keywords
- N-of-1, Ecological Momentary Assessment, Blood pressure, Whole grains, Nuts
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 12 participants (actual)
- Lead sponsor
- University of AberdeenUniversity, hospital or other
- Collaborators
- Biotechnology and Biological Sciences Research Council, Unilever R&D
- Study start
- 30 Oct 2020 (actual)
- Primary completion
- 25 Mar 2022 (actual)
- Study completion
- 25 Mar 2022 (actual)
- First posted
- 30 Mar 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of the study is to investigate whether physiological, psychological and environmental factors, at an individual level, modify a) adherence, and b) blood pressure response, to a nuts and wholegrains intervention in participants at risk for developing high blood pressure. For 24 weeks, participants will, on a daily basis, monitor their own blood pressure using a wireless blood pressure monitor and respond to short semi-personalised questionnaires using a wrist-worn device, which also measures activity levels. Participants will receive an intervention of wholegrain foods and nuts to substitute into their diets for 8 weeks, between two 8-week observation periods. The length of the study periods will enable repeated measurements to be taken, in order to assess what factors, on an individual level, are associated with fluctuations in the outcomes. This will provide an insight into the types of factors that can help to explain individual fluctuations in adherence and physiological outcomes, such as blood pressure, that are common in nutrition studies. In the future, this should help in tailoring the way the investigators deliver effective individualised interventions, and enable researchers to be better able to consider and control for factors that can affect adherence and response to dietary interventions.
Detailed description
The study will be conducted as an interventional N-of-1 study with an A1-B-A2 design of 8 weeks per study period. Prior to the study, participants will be screened and if eligible, will complete a number of baseline questionnaires to provide an overview of their typical eating and lifestyle-related behaviours, and general health. A second visit prior to the start of the study will then be arranged, where participants will undergo a semi-structured interview. Responses from the interview, in combination with their baseline questionnaire responses, will be used to identify factors specific to the participant that show some degree of variability. These will form the basis of the semi-personalised questionnaires delivered via the wrist-worn PRO-Diary device for the duration of the study. During the study, participants will visit the institute in a fasted state every 4 weeks (7 visits total), in order to provide a blood sample for assessment of cholesterol levels and for assessment of biomarkers of wholegrains intake. At the first visit, participants will receive the wireless blood pressure monitor and PRO-Diary wrist device programmed with twice-daily questionnaires at times convenient to the participant. After 2 weeks and every 4 weeks thereafter, participants will be sent a link by email to complete a 24-hour dietary recall. After 8 weeks, participants will begin the intervention phase and receive wholegrains equivalent to 3 portions a day and 1 portion of unsalted nuts per day for the following 8 weeks. Participants will be able to choose from a variety of wholegrain products commonly available at supermarkets. They will also receive dietary advice to follow a Dietary Approaches to Stop Hypertension (DASH) diet aimed at lowering blood pressure. All other measures will continue as previously. At week 16, the wholegrains and nuts will be withdrawn and participants will be followed up for a further 8 weeks. At their final visit to the institute, they will complete the same validated questionnaires as at baseline. Results from the study will be analysed using N-of-1 dynamic modelling to analyse trends over time and determine whether any personalised factors significantly affected adherence to intervention or blood pressure response.
Study design
- Primary purpose
- Prevention
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- This is a series of N-of-1 studies where data from each participant will be analysed separately. Each study follows an A1-B-A2 design consisting of an initial observation phase, an intervention phase and a follow-up phase, each of 8 weeks duration.
| Arm | Type | Receives |
|---|---|---|
| N-of-1 study | Other | Other: Dietary intervention: nuts and wholegrains with dietary advice for a blood-pressure lowering dietFor 24 weeks, each participant will measure their blood pressure and respond to questionnaires daily, and visit the institute to provide a blood sample every 4 weeks. The study is split into three 8-week phases, the first of which will start when each participant is enrolled. For the first 8-week observation phase (A1) the participant is instructed to continue with their usual diet and exercise habits. For the second 8-week intervention phase (B), the participant will be provided with wholegrains and nuts and recommended to substitute these in place of refined grains and other snacks, respectively. They will also receive dietary advice for following the Dietary Approaches to Stop Hypertension (DASH) diet. For the final 8 week follow-up period (A2), provision of wholegrains and nuts will cease but the participant will continue with measurements at the same frequency as previously. |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Mildly elevated blood pressure levels: systolic blood pressure (SBP) >120 <=140mmHg and/or diastolic blood pressure (DBP) >80 <=90mmHg.
- Low habitual intake of wholegrains: <=7 portions/week
- Body Mass Index (BMI) between 18-35
- Possessing a smartphone capable of running the Qardio app in conjunction with the QardioArm wireless blood pressure monitor
Key exclusion criteria (13 listed)
- SBP <120 or >140mmHg or DBP <80 or >90mmHg. Participants with SBP > 140 or DBP > 90 will be advised to visit their GP to have their blood pressure reassessed in a clinical setting.
- Diagnosed with diabetes
- Clinically diagnosed with hypertension or hypercholesterolemia
- Unstable or untreated thyroid disorder
- Taking blood pressure- or cholesterol-lowering medications (e.g. beta blockers or statins)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Dietary intervention: nuts and wholegrains with dietary advice for a blood-pressure lowering diet30g mixed unsalted tree nuts (almonds, hazelnuts and almonds) per day; 3 portions of wholegrain foods per day (including wholegrain cereal products, wholegrain bread and wholegrain pasta); guidance for following the Dietary Approaches to Stop Hypertension (DASH) diet | Other | N-of-1 study |
Primary outcome
Adherence to wholegrains and nuts consumption
Time frame: 8-week intervention period
Number of portions of wholegrains consumed and whether a portion of nuts were consumed, reported daily via the PRO-Diary wrist device.
Change in plasma alkylresorcinol levels reflecting wholegrains intake
Time frame: Every 4 weeks from start of study up to 24 weeks
Concentration of alkylresorcinols as a measure of wholegrains intake in nmol/L
Change in blood pressure
Time frame: From start of study up to 24 weeks
Blood pressure (both systolic and diastolic) will be taken daily by participants via the QardioArm wireless blood pressure monitor. 3 measurements are taken automatically and averaged.
4 secondary outcomes
Correlation between adherence and blood pressure change
Time frame: 8-week intervention period
Total, LDL and HDL cholesterol levels
Time frame: 4-week blood samples
Amount of wholegrains and nuts consumed during follow-up reported using PRO-Diary questionnaires
Time frame: 8-week follow-up phase
Determination of personal factors which correlate with study outcomes using Ecological Momentary Assessment (EMA) through the PRO-Diary device
Time frame: 24 weeks
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 May 2022.
- Derived from this study: PubMed 42049896Potter TIT, Pepping F, Wanders AJ, Zandstra EH, Zock PL, Landberg R, Vieira R, de Roos B. A series of N-of-1 dietary intervention studies with whole-grain foods and nuts reveals individual predictors of blood pressure and heart rate. Eur J Clin Nutr. 2026 Aug;80(8):799-813. doi: 10.1038/s41430-026-01740-3. Epub 2026 Apr 28.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Baukje de Roos principal investigator
The Rowett Institute, University of Aberdeen
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Dietary intervention: nuts and wholegrains with dietary advice for a blood-pressure lowering diet in people with Prehypertension, run by University of Aberdeen at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 17 May 2022. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Adherence to wholegrains and nuts consumption (time frame: 8-week intervention period). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04326686, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 May 2022.