Skip to main content
OpenTrials
Recruiting

NCT Number: NCT06723886

Antidiabetic Effect of Olive Pomace Oil

This clinical trial aims at assessing whether consumption of olive pomace oil in the diet may benefit persons with type 2 diabetes mellitus or persons at risk of developing the disease (prediabetic persons).

The main questions the study aims to answer are:

* May olive pomace oil prevent a high increase of blood glucose levels when consumed in a meal together with carbohydrates in diabetic/prediabetic patients? * May olive pomace oil decrease fasting blood glucose levels of diabetic/prediabetic patients after consuming it daily? * May daily consumption of olive pomace oil improve glucose homeostasis and other alterations like elevated blood lipids or inflammation, which also affect persons with diabetes or prediabetes?

Researchers will compare the effect of consuming olive pomace oil to the effects of a comparison oil (high-oleic acid sunflower oil).

Participants will:

In different days, they will consume white bread alone or the oils (olive pomace oil, high-oleic acid sunflower oil or extra virgin olive oil) spread on white bread and blood will be collected at different times during 2 h. This study to observe the increase of blood glucose after a carbohydrate-rich breakfast will be part of the so-called "postprandial" study, and will be conducted during 3 weeks, during which participants will consume corn oil on a daily basis.

Participants will also take part in the "chronic" study, that will last 22 weeks in total. During this study, they will firstly "wash" the effects of the oil they normally consume in their diets by consuming corn oil during 3 weeks. It is during these weeks when they will attend the Human Nutrition Unit (HNU) of ICTAN to carry on the "postprandial" study described in the previous paragraph.

After the initial 3 weeks, participants will consume olive pomace oil as the only oil in their diets during 8 weeks, "wash" its effects again by consuming corn oil during 3 weeks and then change to consume the other oil (high-oleic acid sunflower oil) during 8 weeks.

During the chronic study, they will visit the clinic once every 4 weeks for checkups and tests. They will refrain from eating other oils or specific fat-rich foods. Participants will also attend our phone calls to ask them what they ate the day before on different weeks during the study, and wear an accelerometer during 1 week to record their physical activity. They will keep a diary of the doses of insulin/metformin used and the blood glucose levels they measured at home.

Recruiting

Interested in participating?

Request Info

Key information

Age range

20 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Institute of Food Science, Technology and Nutrition (ICTAN-CSIC)

Madrid, 28040, Spain

Location status: Recruiting

Location contact

Beatriz Sarria, Dr

CONTACT

[email protected]

+34 91 5492300 ext. 436342

Laura Bravo, Professor

CONTACT

[email protected]

+34 91 5492300 ext. 436350

Álvaro Fernandez-Cardero, MSc

CONTACT

About this study

This trial comprises 2 studies in parallel, a postprandial study and a chronic intervention.

In the postprandial study, participants will attend the Human Nutrition Unit (HNU) of ICTAN in different days. During these visits, they will consume white bread (50 g) alone or with 10 g of extra virgin olive oil (EVOO), olive pomace oil (OPO) or high-oleic acid sunflower oil (HOSO). A nurse will insert a catheter in the non-prevailing arm and collect fasting blood (0 h) and blood samples 1 and 2 h after consuming the bread/oil to measure the postprandial glycemic/insulinemic response, as well as incretins (GLP-1, GIP). Blood lipids will also be determined. These visits will be carried out during the 3-week run-in period prior to the chronic intervention, when the EVOO and control (white bread) tests will be carried out (weeks 1 and 2, respectively). Then, coinciding with the first day of the chronic intervention, participants will consume either OPO or HOSO as corresponding to the randomized allocation to each oil. The other postprandial test will be carried out at the beginning of the second intervention after crossover and wash-out, thus avoiding additional visits and discomfort to the participants.

The chronic study is a crossover, randomized, blind, clinical trial. After a 3-week run-in during which participants will consume corn oil as the only dietary oil, they will be randomly allocated to one of each intervention arms, OPO or HOSO, each lasting 8 weeks. Then, a 3-week wash-out period with corn oil will follow before changing to consuming the other oil.

During the study, participants should avoid other oils and fats such as olives, sunflower seeds, butter, margarine, nuts or avocados.

During the chronic intervention, participants will visit the HNU at the beginning (week 1), middle (week 4) and at the end (week 8) of each intervention arm. A nurse will collect a fasting blood sample and measure blood pressure. An analysis of body weight and body composition (anthropometric and bioimpedance measurements) will be performed. Participants should maintain their habitual diet and exercise level throughout the study; diet will be monitored by periodic 24-h recall questionnaires (a trained member of the team will phone participants on 3 different days (including a festive one) before each visit to the HNU to enquire what they ate the previous day). In addition, a physical activity questionnaire will be completed at the beginning of the study and, on each intervention arm, participants will carry during 7 days an accelerometer to monitor real physical activity.

Biochemical, hormonal and inflammatory markers will be measured in blood samples to assess the potential effect of olive pomace oil on different outcomes of relevance in the management of blood glucose in diabetic/prediabetic persons, including glucose homeostasis, insulin resistance, blood lipid levels, liver function, different hormones, incretins, adipokines, pro- and anti-inflammatory cytokines, on integrity of the intestinal barrier.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Fasting blood glucose between 100-126 mg/dL and/or
  • Glycated haemoglobin (HbA1c) between 5.7-6.4% and/or
  • Diabetic persons with Fasting blood glucose >126 mg/dL and/or
  • Diabetic persons with Glycated haemoglobin (HbA1c) > 6.4%

Exclusion criteria

  • Kidney or liver diseases
  • Gastrointestinal diseases (irritable bowel syndrome, Crohn disease, chronic bowel inflammation)
  • Food allergies/intolerances
  • Vegetarians/vegans
  • Smoking
  • Pregnant or lactating women
  • On prescription drugs other than for hypertension/thyroid/dyslipidemia/glucose control, or changes in dosage in the last 3 months
  • Consumption of vitamins, dietary supplements or nutraceuticals

Treatment and study plan

Experimental arm: Olive pomace oil

Dietary Supplement

Participants will consume during 8 weeks either the test oil (olive pomace oil) as the only dietary fat. They will consume 45 g/day of oil, using it in salads, fried foods, as spread on toasts, etc.

High-oleic acid sunflower oil

Dietary Supplement

Participants will consume during 8 weeks either the test active comparator oil (high-oleic acid sunflower oil) as the only dietary fat. They will consume 45 g/day of oil, using it in salads, fried foods, as spread on toasts, etc.

Primary outcomes

  1. Fasting blood glucose

    Time frame: From enrollment to the end of each treatment at 8 weeks

    Change of fasting blood glucose levels at the end of the chronic intervention

  2. Postprandial blood glucose response

    Time frame: From enrollment until week 14 of the study

    Change of postprandial blood glucose levels after consuming white bread with oil in comparison with white bread only.

    Blood will be collected at 0 h and 1 and 2 h after consuming the bread alone or with the corresponding oil. Olive pomace oil (active comparator) and high-oleic acid sunflower oil (active comparator) will be tested. Only in this postprandial study extra virgin olive oil will also be tested as a positive control (at the beginning of the run-in), along with white bread only (at week 2 of the run-in). Test/comparator oils will be assessed at the beginning of each arm, week 1 of each intervention arm (corresponding to weeks 4 and 14 of the study).

Secondary outcomes

  1. Insulin levels

    Time frame: From enrollment to the end of each treatment at 8 weeks

    Change in fasting blood insulin levels at the end of the chronic intervention

  2. Insulin resistance

    Time frame: From enrollment to the end of each treatment at 8 weeks

    Change in homeostasis model assessment (HOMA) of insulin resistance (HOMA-IR) at the end of the chronic intervention

  3. Insulin sensitivity

    Time frame: From enrollment to the end of each treatment at 8 weeks

    Change in quantitative insulin levels sensitivity check index (QUICKI) at the end of the chronic intervention. Higher score in QUICKI means a better outcome compared to initial values.

  4. Glycated hemoglobin

    Time frame: From enrollment to the end of each treatment at 8 weeks

    Change in blood levels of glycated hemoglobin (HbA1c) at the end of the chronic intervention

  5. Beta-cell function

    Time frame: From enrollment to the end of each treatment at 8 weeks

    Change in homeostasis model assessment (HOMA) of beta-cell function (HOMA-B) at the end of the chronic intervention

  6. Postprandial insulin response

    Time frame: From enrollment to week 14 of the study

    Change of postprandial blood insulin levels after consuming white bread with oil in comparison with white bread only.

    Blood will be collected at 0 h and 1 and 2 h after consuming the bread alone or with the corresponding oil. Olive pomace oil (active comparator) and high-oleic acid sunflower oil (active comparator) will be tested. Only in this postprandial study extra virgin olive oil will also be tested as a positive control (at the beginning of the run-in), along with white bread only (at week 2 of the run-in). Test/comparator oils will be assessed at the beginning of each arm, week 1 of each intervention arm (corresponding to weeks 4 and 14 of the study).

  7. Postprandial incretins

    Time frame: From enrollment to week 14 of the study

    Change of postprandial levels of GLP-1 and GIP after consuming white bread with oil in comparison with white bread only.

    Blood will be collected at 0 h and 1 and 2 h after consuming the bread alone or with the corresponding oil. Olive pomace oil (active comparator) and high-oleic acid sunflower oil (active comparator) will be tested. Only in this postprandial study extra virgin olive oil will also be tested as a positive control (at the beginning of the run-in), along with white bread only (at week 2 of the run-in). Test/comparator oils will be assessed at the beginning of each arm, week 1 of each intervention arm (corresponding to weeks 4 and 14 of the study).

  8. Postprandial blood lipids

    Time frame: From enrollment to week 14 of the study

    Change of postprandial blood lipid levels after consuming white bread with oil in comparison with white bread only.

    Blood will be collected at 0 h and 1 and 2 h after consuming the bread alone or with the corresponding oil. Olive pomace oil (active comparator) and high-oleic acid sunflower oil (active comparator) will be tested. Only in this postprandial study extra virgin olive oil will also be tested as a positive control (at the beginning of the run-in), along with white bread only (at week 2 of the run-in). Test/comparator oils will be assessed at the beginning of each arm, week 1 of each intervention arm (corresponding to weeks 4 and 14 of the study).

Other outcomes

  1. Blood lipids

    Time frame: From enrollment to the end of each treatment at 8 weeks

    Change in serum levels of total cholesterol or LDL-cholesterol or HDL-cholesterol or triglycerides or apolipoprotein A1 or apolipoprotein B at the end of the chronic intervention

  2. Inflammatory cytokines

    Time frame: From enrollment to the end of each treatment at 8 weeks

    Change in the levels of C-reactive protein (CRP), or pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-a), or interferon gamma (IFN-g), or interleukin (IL)-1beta (IL-1b), or IL-2, or IL-5, or IL-6, or IL-7, or IL-8, or IL-13)) or anti-inflammatory cytokines IL-4 or IL-10 at the end of the chronic intervention

  3. Liver function

    Time frame: From enrollment to the end of each treatment at 8 weeks

    No changes in serum levels of alanine transferase (ALAT), or aspartate transferase (ASAT) or gamma-glutamyl transferase (GGT) at the end of the chronic intervention

  4. Hormones, incretins and adipokines levels

    Time frame: From enrollment to the end of each treatment at 8 weeks

    Changes in serum levels of C peptide or glucagon or fibroblast growth factor 21 (FGF21) or glucagon inhibitory peptide (GIP) or glucagon-like peptide type 1 (GLP-1) or ghrelin or leptin or resistin or plasminogen activator inhibitor type 1 (PAI-1) or visfatin or adiponectin or adipsin or dipeptidyl peptidase IV (DPP IV) at the end of the chronic intervention

  5. Intestinal barrier function

    Time frame: From enrollment to the end of each treatment at 8 weeks

    Changes in blood levels of lipopolysaccharide (LPS) or zonulin at the end of the chronic intervention

Study contacts

Contact information is provided by the study sponsor or research team.

Beatriz Sarria, Dr

CONTACT

[email protected]

+34 91 5492300 ext. 436342

Laura Bravo, Professor

CONTACT

[email protected]

+34 91 5492300 ext. 436350

Sponsors and collaborators

Lead sponsor

Instituto de Ciencia y Tecnología de Alimentos y Nutrición

Other Gov

Collaborators

  • ICTAN-CSIC - Madrid - Spain

Registry information

Official study title

Assessment of the Potential Antidiabetic Effects of Olive Pomace Oil in Diabetic or Prediabetic Subjects: Postprandial Study and Chronic Intervention

Acronym: OPODIABE

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Dec 9, 2024
Registry last updated
Dec 11, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.