Condition category
Nutritional, Metabolic, Endocrine
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status
Results overdue

Plain English Summary

Background and study aims
Several studies have reported the health benefits of grape pomace (GP) supplementation since it is a dietary source of polyphenols and fiber. GP is a good candidate for a clinical trial of the management of both blood pressure and glucose levels. Moreover, grape pomace has promising sensory potential as a condiment in food but this property is still not scientifically proven. This trial is included in a R+D+i Project (INGRAPE) funded by the Spanish Ministry of Science and Innovation, the aim of which is to assess the use of GP seasoning as a salt replacer in foods to reduce markers of high blood pressure and high blood sugar in people at risk.

Who can participate?
Participants with at least two of the following risk factors: high blood pressure (systolic ≥130 mmHg or diastolic >85 mmHg), high blood cholesterol (HDL cholesterol <40 mg/dl in men and <50 mg/dl in women), high blood fats (triglycerides >150 mg/dl), increased fasting blood sugar (>100 mg/dl), increased waist size (> 94 cm in men and > 80 cm in women)

What does the study involve?
Participants will undergo 6 weeks of reducing salt in their food (control group) or supplementation with 2 g/day of grape pomace seasoning as a salt replacer (treatment group). Participants provide samples of faeces, saliva and blood for analysis at the start and the end of the study.

What are the possible benefits and risks of participating?
The researchers expect the GP seasoning to reduce blood pressure and blood sugar levels and cause changes in gut bacteria. Therefore, the participants in the intervention group will benefit from these potential health effects. In a general way, all participants will get satisfaction from contributing to a study that could lead to an interesting strategy to manage high blood pressure and blood sugar. As far as the researchers are aware, participating does not lead to additional risks.

Where is the study run from?
CIAL-Institute of Food Science Research, Spanish National Council (CSIC) (Spain)

When is the study starting and how long is it expected to run for?
December 2016 to November 2019

Who is funding the study?
Spanish Ministry of Science and Innovation (Spain)

Who is the main contact?
1. Diego Taladrid
2. Begoña Bartolomé
3. Dr M. Victoria Moreno Arribas

Trial website

Contact information



Primary contact

Dr M. Victoria Moreno Arribas


Contact details

c/Nicolás Cabrera
+34 (0)910017900

Additional identifiers

EudraCT number

Nil known number

Nil known

Protocol/serial number


Study information

Scientific title

Nutritional intervention with a new seasoning from grape pomace in people at risk of metabolic syndrome to manage blood pressure and glycaemia



Study hypothesis

Grape pomace has demonstrated before its functional properties in the management of risk factors of metabolic syndrome. Moreover, grape pomace has an underestimated culinary potential.

Ethics approval

Approved 16/05/2017, The Spanish National Research Council Ethics Committee (117 Serrano Street, Madrid, 28006, Spain; +34 (0)915681494;, ref: RTC-2016-4556-1

Study design

Interventional controlled randomized controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not avaliable in web format, please use contact details to request a participant information sheet


Management of metabolic risk factors of metabolic syndrome


First, volunteers will receive information about the study, a survey of dietary habits and several recipes low in sodium salt. In addition, they will have to sign a printed consent to participate in the study, donate their biological samples and to ensure confidentially of the data.

Then, participants will be allocated randomly to the control and treatment groups. All of them will go through a washout period in which they will have to reduce their intake of polyphenol-rich foods for 2 weeks. After that, both sets of volunteers will have to reduce the consumption of sodium salt during the 6 weeks of the clinical trial. Furthermore, the treatment group will have to consume 2 g/day of grape pomace as sodium salt replacer in their foods.

The first day after the washout period and the last day of the intervention period, all of the participants will go to the collection place between 8:00-10:00 after at least 10 hours of fasting. Then, they will deliver a sample of faeces taken as recent to this moment as possible (in a stool collection tube introduced in an anaerobic plastic zip bag). Then they will have to spit into a 15 ml Falcon tube to obtain at least 3 ml of saliva.

After the delivery of the samples, anthropometric data of height, weight and waist circumference will be taken. In addition, blood pressure will be measured during relaxation in triplicate using a digital oscillometric device (Omron model M6 Comfort, Omron Corporation, Tokyo, Japan) and employing at least two readings.

By last, participants will be allocated one by one to a contiguous room where a sample of blood will be taken by a specialist belonging to an independent laboratory, who is also responsible for the blood analysis.

Intervention type



Drug names

Primary outcome measure

1. Full serum count, erythrocyte sedimentation rate, c-reactive protein, sodium, potassium, chloride, bicarbonate, urea, creatinine, bilirubin, gamma-glutamyl transferase, total protein, albumin, calcium, phosphate, uric acid, random blood glucose, cholesterol, high-density lipoprotein, low-density lipoprotein and triglycerides; measured using a blood test at baseline and at the end of the control/intervention period
2. Blood pressure (mmHg), height (cm), weight (kg), waist diameter (cm) and hip circumference (cm) measured at baseline and at the end of the control/intervention period

Secondary outcome measures

1. Short-chain fatty acids (SCFA) and phenolic metabolites analysed in faecal samples by gas chromatography–mass spectrometry (GC-MS) and ultra-high performance liquid chromatography mass spectrometry (UHPLC–MS), respectively, according to previous laboratory procedures at baseline and at the end of the control/intervention period
2. Microbiota sequencing analysis of faecal samples following a bacteria metagenomic approach (Illumina technology) at baseline and at the end of the control/intervention period

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

Participants have to present at least two of the following risk factors of metabolic syndrome:
1. Hypertension (systolic BP ≥130 mmHg or diastolic BP >85 mmHg)
2. Hypercholesterolemia (HDL colesterol <40 mg/dl in men and <50 mg/dl in women)
3. Hypertriglyceridemia (triglycerides >150 mg/dl)
4. Increased fasting plasma glucose (>100 mg/dl)
5. Increased waist circumference (>94 cm in men and >80 cm in women)

Participant type


Age group




Target number of participants


Total final enrolment


Participant exclusion criteria

1. Serious cardiovascular disease
2. Antibiotic intake up to 3 months before the study
3. Endocrine and gastrointestinal disorders
4. Addiction to drugs or alcohol
5. Restrictive diets (vegetarians, vegans)

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Instituto de Investigación en Ciencias de la Alimentación
Nicolás Cabrera street, 9

Sponsor information


Institute of Food Science Research

Sponsor details

c/ Nicolas Cabrera
+34 (0)910017900

Sponsor type

Research organisation



Funder type


Funder name

Ministerio de Asuntos Económicos y Transformación Digital

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

1. Planned publication in a high-impact journal
2. Participants desiring to know the outcomes of the study will be informed individually by email
3. The protocol and the statistical analysis will be available when the results are published in a scientific journal

IPD sharing statement
The datasets generated during and/or analysed during the current study (serum blood analytics, anthropometrical data, blood pressure, faecal metabolites and sequencing data) are/will be available upon request from Diego Taladrid (, Begoña Bartolomé (, and M.Victoria Moreno-Arribas ( Data were anonymized but participants desiring to know the outcomes of the study were informed individually of their corresponding data by email.

Intention to publish date


Participant level data

Available on request

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

12/11/2020: Trial's existence confirmed by the Spanish National Research Council Ethics Committee.