Condition category
Circulatory System
Date applied
27/10/2010
Date assigned
27/10/2010
Last edited
02/06/2015
Prospective/Retrospective
Retrospectively registered
Overall trial status
Completed
Recruitment status
No longer recruiting

Plain English Summary

Not provided at time of registration

Trial website

Contact information

Type

Scientific

Primary contact

Dr Sumanto Haldar

ORCID ID

Contact details

School of Agriculture Food and Rural Department
Claremont Road
Newcastle Upon Tyne
NE1 7RU
United Kingdom
-
sumanto.haldar@ncl.ac.uk

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

8420

Study information

Scientific title

Effects of increased consumption of leaf and stalk vegetables and beetroot on cardiovascular function: VegBP project

Acronym

VegBP

Study hypothesis

Cardiovascular diseases (CVD) are the principal cause of death and morbidity in the UK and the risk of CVD is directly related to increases in blood pressure. Therefore, it is essential to maintain blood pressure within an optimal range in order to reduce CVD risk. Previous epidemiological studies suggested that increased fruits and vegetables intake may reduce blood pressure, although the specific type(s) of fruits and/or vegetables which are responsible for this effect is not known. In particular, green leafy or other salad vegetables (such as beetroot) high in nitrates may be responsible, since nitric oxide formed naturally in the body from these nitrates play an important role in maintaining the function of blood vessels.

Therefore, in the present study we will investigate effects of increased consumption of green-leafy or other salad vegetables on blood pressure in comparison with other vegetables such as carrots, broccoli (low in nitrates). Volunteers recruited will be instructed to avoid all vegetables that are high in nitrates from a list provided for the first eight weeks of the study. After this 'washout' period, volunteers will be randomly assigned to three different groups. Each group will be asked to have 100 g/day of specific vegetables in addition to their normal diet for a further 16 weeks. Group 1 will have green-leafy or other salad vegetables, Group 2 will have other vegetables (low in nitrates) and Group 3 will have half of each type of vegetables as consumed by Groups 1 and 2.

Using non-invasive devices, resting blood pressure, 24 hour blood pressure and flow in blood vessels (using ultrasound) in the arm will be measured at the start of the study and after every 8 weeks throughout the study. Blood and saliva samples will also be collected during these occasions to monitor biochemical changes related to specific vegetable intake and monitor compliance to the study protocol.

Ethics approval

MREC approved on 22/06/2010, ref: 10/H0908/27

Study design

Single-centre randomised interventional prevention trial

Primary study design

Interventional

Secondary study design

Randomised controlled trial

Trial setting

GP practices

Trial type

Prevention

Patient information sheet

Condition

Topic: Primary Care Research Network for England, Cardiovascular, Generic Health Relevance and Cross Cutting Themes; Subtopic: Not Assigned, Cardiovascular (all Subtopics), Generic Health Relevance (all Subtopics); Disease: Cardiovascular, All Diseases, Public Health Research

Intervention

Vegetable Group 1: Additional consumption of 100 g per day of vegetables from mixed leaf lettuce, beetroot and spinach for a 16-week intervention period
Vegetable Group 2: Additional consumption of 100 g per day of vegetables from yellow tomatoes, peas and sweetcorn for a 16-week intervention period
Vegetable Group 3: Additional consumption of 50 g per day of vegetables from mixed leaf lettuce, beetroot and spinach and 50 g per day of vegetables from peas, sweetcorn and yellow tomatoes for a 16-week intervention period

Follow up length: 6 months
Study entry: single randomisation only

Intervention type

Other

Phase

Not Applicable

Drug names

Primary outcome measures

Seated Blood Pressure, measured twice within 1 week every 8 weeks over a 24 week period (8 times in total).

Secondary outcome measures

1. 24-hour ambulatory blood pressure, measured once every 8 weeks over a 24-week period (4 measurements in total)
2. C-reactive protein (CRP) and biochemical markers of endothelial function, measured twice within 1 week every 8 weeks over a 24-week period (8 times in total)
3. Fasting blood glucose, measured once every 8 weeks over a 24-week period (4 measurements in total)
4. Fasting blood lipid profile, measured twice within 1 week every 8 weeks over a 24-week period (8 measurements in total)
5. Flow mediated dilation, measured once every 8 weeks over a 24-week period (4 measurements in total)
6. Plasma carotenoids and polyphenols, measured twice within 1 week every 8 weeks over a 24-week period (8 times in total)
7. Weight and body composition, measured once every 8 weeks over a 24-week period (4 times in total)

Overall trial start date

15/07/2010

Overall trial end date

17/12/2012

Reason abandoned

Eligibility

Participant inclusion criteria

1. Male or female subjects aged 40 - 75 years
2. Systolic blood pressure in the range 130 - 150 mmHg

Participant type

Patient

Age group

Adult

Gender

Both

Target number of participants

Planned sample size: 225; UK sample size: 225

Participant exclusion criteria

1. Body mass index (BMI) greater than 30 kg/m2
2. Habitual consumption of green leafy vegetables higher than the population mean (= exclusion of the highest quartile, since the distribution of intake is highly skewed)
3. Recent or current serious disease (cancer, cardiovascular disease [CVD], etc.)
4. History of persistent gastric reflux or H. pylori infection
5. Allergies or intolerances to intervention foods
6. Planning to change dietary habits, increase physical activity, change body weight or move away from the study locality during the time of the study
7. Smokers
8. Taking antihypertensives for elevated blood pressure
9. Taking prescribed nitrates for angina or heart failure
10. Taking statins
11. History of substance abuse or alcoholism

Recruitment start date

15/07/2010

Recruitment end date

17/12/2012

Locations

Countries of recruitment

United Kingdom

Trial participating centre

Newcastle University
Newcastle Upon Tyne
NE1 7RU
United Kingdom

Sponsor information

Organisation

Newcastle upon Tyne Hospitals NHS Foundation Trust (UK)

Sponsor details

Midwifery Research Department
Leazes Wing
Queen Victoria Road
Newcastle upon Tyne
NE1 4LP
United Kingdom

Sponsor type

Government

Website

http://www.newcastle-hospitals.org.uk/

Funders

Funder type

Government

Funder name

Food Standards Agency (FSA) (UK) (ref: N02046)

Alternative name(s)

FSA

Funding Body Type

private sector organisation

Funding Body Subtype

other non-profit

Location

United Kingdom

Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes