Cardiometabolic SyndromeOMNIVEGNCT06008886
Effect of a Vegan Diet Versus a Mediterranean Diet. Assessing Health Outcomes
A study testing Vegan diet and Mediterranean diet in people with Cardiometabolic Syndrome, run by Universidad Francisco de Vitoria at 1 site in Spain.
Trial summary
This study aimed to evaluate the effect of a vegan diet (supplemented with vitamin B12) and an mediterranean diet on performance, cardiorespiratory fitness, metabolic health, immune status, and environmental impact in healthy adults. Read more about this study
- Who is it for?
- Ages 18 to 40 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Cardiometabolic Syndrome
- What is being tested?
- Vegan diet and Mediterranean diet
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 14 participants
- Where
- 1 siteSpain
- Study dates
- 19 Jun 2023to 4 Sep 2023
- 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 40 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Men.
- Aged between 18-40 years.
- Physically active according to the recommendations of the World Health Organization (WHO).
- Body Mass Index (BMI) between 18.5-24.9 kg/m2.
- No tobacco use.
- No or low alcohol consumption and no orthopedic limitations that would interfere with the performance of the study tests.
Who cannot join
- Chronic diseases that impair athletic performance (cardiovascular, metabolic, gastrointestinal, respiratory) within the last six months.
- Musculoskeletal disease within the last six months.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Effect of a Vegan Diet Versus a Mediterrean Diet on Performance, Cardiorespiratory Fitness, Metabolic Health, Immune Status, and Environmental Impact in Healthy Adults
This study aimed to evaluate the effect of a vegan diet (supplemented with vitamin B12) and an mediterranean diet on performance, cardiorespiratory fitness, metabolic health, immune status, and environmental impact in healthy adults.
Read the detailed description
OMNIVEG is a controlled crossover trial. Initially, registered dietitians conducted an assessment of participants' lifestyles in a preliminary session. Qualified nutritionists then developed personalized diets for each participant in accordance with the recommendations of the International Society of Sports Nutrition (ISSN). These diets followed specific guidelines, including a daily intake of 3-5 g of carbohydrates per kilogram of body weight, 1.4-2.0 g of protein per kilogram of body weight, and 0.5-1.5 g of fat per kilogram of body weight.
Both the mediterranean diet and vegan diets prescribed to the participants were isocaloric, with similar distributions of macronutrients. The primary difference between the two interventions was the source of food: the vegan diet exclusively comprised plant-based foods, while the omnivorous diet included foods of both animal and plant sources. In the case of the omnivorous diet, 60% of the total protein intake was derived from animal sources (mainly from fish, white meat, low-fat dairy and eggs).
As part of the vegan diet, participants were instructed to take 1000 µg of cyanocobalamin (a form of vitamin B12) twice a week from Harrison Sport Nutrition, Granada, Spain. This supplementation aimed to ensure adequate vitamin B12 intake, which is essential for individuals following a vegan diet.
Throughout the study period, participants were advised to maintain their initial physical exercise frequency and volume to maintain consistency and avoid confounding variables. To ensure standardized measurements, all tests were conducted in the same laboratory, employing identical testing devices, and supervised by the same group of researchers. This approach aimed to minimize experimental variability and improve the reliability of the study's results.
- Conditions
- Cardiometabolic Syndrome
- Being tested
- Vegan diet, Mediterranean diet
- Keywords
- Plant-Based Diet, Environmental Impact, Cardiorespiratory Fitness, Performance, Metabolic Health, Mediterranean diet, Vegan diet
- Medical subject headings
- Metabolic Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Vegan dietBehavioural
Normocaloric diet based solely on foods of plant sources.
Mediterranean dietBehavioural
Diet with a predominance of plant foods fruits, vegetables, whole grains, nuts and legumes); moderate to low consumption of fish, white meat, low-fat dairy and eggs; and very low consumption of red and processed meats, butter, full-fat dairy and sweets.
| Study group | Role | What they receive |
|---|---|---|
| Vegan diet | Experimental | Vegan diet all foods included were of plant sources. During the vegan diet, the participants took 1000 µg of cyanocobalamin twice a week (Harrison Sport Nutrition, Granada, Spain) Receives: Behavioral: Vegan diet |
| Mediterranean diet | Active comparator | In the case of the mediterranean diet, foods of animal sources were also included (animal protein accounted for 60% of total protein intake). In this diet there was a predominance of plant foods; moderate to low consumption of fish, white meat, low-fat dairy and eggs; and very low consumption of red and processed meats, butter, full-fat dairy and sweets. Receives: Behavioral: Mediterranean diet |
What is being measured
The primary outcome is the main question the study is designed to answer.
Cardiorespiratory fitness
Cardiorespiratory fitness was measured using Maximal oxygen uptake (VO2max).
Measured: 4 weeks
Metabolic health
Metabolic health was measured using serum total cholesterol (TC), cholesterol-LDL (LDL-c) and colesterol-HDL (HDL-c)
Measured: 4 weeks
Performance
Performance was measured using FATmax (g/min).
Measured: 4 weeks
Performance
Performance was measured using countermovement (CMJ) (W) and squat jump (SJ).
Measured: 4 weeks
Performance
Performance was measured using squat jump (SJ) (W)
Measured: 4 weeks
Environmental impact assessment
Environmental impact was measured using Global-warming potential-100
Measured: 4 weeks
Inmune status
Inmune status was measured using lymphocyte levels (109/L )
Measured: 4 weeks
Secondary outcomes (4)
Performance
Performance was measured using handgrip
Measured: 4 weeks
Metabolic health
Metabolic health was measured using systolic blood pressure (SBP) and diastolic blood pressure (DBP).
Measured: 4 weeks
Inmune status
Inmune status was measured using monocyte, eosinophils and neutrophils levels (10^9/L)
Measured: 4 weeks
Environmental impact assessment
Environmental impact was measured using blue water footprint and land use.
Measured: 4 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Aug 2023
- Study start19 Jun 2023
- Primary completion28 Aug 2023
- Study completion4 Sep 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Cardiometabolic SyndromeStudies 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
- Non-randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 14 participants (actual)
Sponsor and investigators
- Lead sponsor
- Universidad Francisco de Vitoria
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Miguel López Moreno, Universidad Francisco de Vitoria
- Investigators
- Miguel López Moreno, Phd, Principal investigator, Universidad Francisco de Vitoria
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06008886
- Sponsor's protocol ID
- 20/2023
- Acronym
- OMNIVEG
- Status last verified
- Aug 2023
- First submitted
- 28 Jul 2023
- Last updated
- 28 Nov 2023
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Lopez-Moreno M, Fresan U, Del Coso J, Munoz A, Aguilar-Navarro M, Iglesias-Lopez MT, Amaro-Gahete FJ, Gutierrez-Hellin J. The OMNIVEG Study: Effects of Transitioning from a Traditional to a Vegan Mediterranean Diet on Fat Oxidation During Exercise. Nutrients. 2025 Jul 9;17(14):2274. doi: 10.3390/nu17142274.
PubMed 40732902Lopez-Moreno M, Fresan U, Del Coso J, Aguilar-Navarro M, Iglesias Lopez MT, Pena-Fernandez J, Munoz A, Gutierrez-Hellin J. The OMNIVEG STUDY: Health outcomes of shifting from a traditional to a vegan Mediterranean diet in healthy men. A controlled crossover trial. Nutr Metab Cardiovasc Dis. 2024 Dec;34(12):2680-2689. doi: 10.1016/j.numecd.2024.08.008. Epub 2024 Aug 23.
PubMed 39358106
Study at a glance
From the registry record, last updated by the sponsor on 28 Nov 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of a Vegan Diet Versus a Mediterrean Diet on Performance, Cardiorespiratory Fitness, Metabolic Health, Immune Status, and Environmental Impact in Healthy Adults
- ClinicalTrials.gov ID
- NCT06008886
- Acronym / sponsor ID
- OMNIVEG / 20/2023
- Conditions
- Cardiometabolic Syndrome
- Keywords
- Plant-Based Diet, Environmental Impact, Cardiorespiratory Fitness, Performance, Metabolic Health, Mediterranean diet, Vegan diet
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 14 participants (actual)
- Lead sponsor
- Universidad Francisco de VitoriaUniversity, hospital or other
- Study start
- 19 Jun 2023 (actual)
- Primary completion
- 28 Aug 2023 (actual)
- Study completion
- 4 Sep 2023 (actual)
- First posted
- 24 Aug 2023 (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.
This study aimed to evaluate the effect of a vegan diet (supplemented with vitamin B12) and an mediterranean diet on performance, cardiorespiratory fitness, metabolic health, immune status, and environmental impact in healthy adults.
Detailed description
OMNIVEG is a controlled crossover trial. Initially, registered dietitians conducted an assessment of participants' lifestyles in a preliminary session. Qualified nutritionists then developed personalized diets for each participant in accordance with the recommendations of the International Society of Sports Nutrition (ISSN). These diets followed specific guidelines, including a daily intake of 3-5 g of carbohydrates per kilogram of body weight, 1.4-2.0 g of protein per kilogram of body weight, and 0.5-1.5 g of fat per kilogram of body weight.
Both the mediterranean diet and vegan diets prescribed to the participants were isocaloric, with similar distributions of macronutrients. The primary difference between the two interventions was the source of food: the vegan diet exclusively comprised plant-based foods, while the omnivorous diet included foods of both animal and plant sources. In the case of the omnivorous diet, 60% of the total protein intake was derived from animal sources (mainly from fish, white meat, low-fat dairy and eggs).
As part of the vegan diet, participants were instructed to take 1000 µg of cyanocobalamin (a form of vitamin B12) twice a week from Harrison Sport Nutrition, Granada, Spain. This supplementation aimed to ensure adequate vitamin B12 intake, which is essential for individuals following a vegan diet.
Throughout the study period, participants were advised to maintain their initial physical exercise frequency and volume to maintain consistency and avoid confounding variables. To ensure standardized measurements, all tests were conducted in the same laboratory, employing identical testing devices, and supervised by the same group of researchers. This approach aimed to minimize experimental variability and improve the reliability of the study's results.
Study design
- Primary purpose
- Prevention
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Vegan diet | Experimental | Behavioral: Vegan dietVegan diet all foods included were of plant sources. During the vegan diet, the participants took 1000 µg of cyanocobalamin twice a week (Harrison Sport Nutrition, Granada, Spain) |
| Mediterranean diet | Active comparator | Behavioral: Mediterranean dietIn the case of the mediterranean diet, foods of animal sources were also included (animal protein accounted for 60% of total protein intake). In this diet there was a predominance of plant foods; moderate to low consumption of fish, white meat, low-fat dairy and eggs; and very low consumption of red and processed meats, butter, full-fat dairy and sweets. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- Men.
- Aged between 18-40 years.
- Physically active according to the recommendations of the World Health Organization (WHO).
- Body Mass Index (BMI) between 18.5-24.9 kg/m2.
- No tobacco use.
Key exclusion criteria (2 listed)
- Chronic diseases that impair athletic performance (cardiovascular, metabolic, gastrointestinal, respiratory) within the last six months.
- Musculoskeletal disease within the last six months.
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 |
|---|---|---|
| Vegan dietNormocaloric diet based solely on foods of plant sources. | Behavioural | Vegan diet |
| Mediterranean dietDiet with a predominance of plant foods fruits, vegetables, whole grains, nuts and legumes); moderate to low consumption of fish, white meat, low-fat dairy and eggs; and very low consumption of red and processed meats, butter, full-fat dairy and sweets. | Behavioural | Mediterranean diet |
Primary outcome
Cardiorespiratory fitness
Time frame: 4 weeks
Cardiorespiratory fitness was measured using Maximal oxygen uptake (VO2max).
Metabolic health
Time frame: 4 weeks
Metabolic health was measured using serum total cholesterol (TC), cholesterol-LDL (LDL-c) and colesterol-HDL (HDL-c)
Performance
Time frame: 4 weeks
Performance was measured using FATmax (g/min).
Performance
Time frame: 4 weeks
Performance was measured using countermovement (CMJ) (W) and squat jump (SJ).
Performance
Time frame: 4 weeks
Performance was measured using squat jump (SJ) (W)
Environmental impact assessment
Time frame: 4 weeks
Environmental impact was measured using Global-warming potential-100
Inmune status
Time frame: 4 weeks
Inmune status was measured using lymphocyte levels (109/L )
4 secondary outcomes
Performance
Time frame: 4 weeks
Metabolic health
Time frame: 4 weeks
Inmune status
Time frame: 4 weeks
Environmental impact assessment
Time frame: 4 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 28 Nov 2023.
- Derived from this study: PubMed 40732902Lopez-Moreno M, Fresan U, Del Coso J, Munoz A, Aguilar-Navarro M, Iglesias-Lopez MT, Amaro-Gahete FJ, Gutierrez-Hellin J. The OMNIVEG Study: Effects of Transitioning from a Traditional to a Vegan Mediterranean Diet on Fat Oxidation During Exercise. Nutrients. 2025 Jul 9;17(14):2274. doi: 10.3390/nu17142274.
- Derived from this study: PubMed 39358106Lopez-Moreno M, Fresan U, Del Coso J, Aguilar-Navarro M, Iglesias Lopez MT, Pena-Fernandez J, Munoz A, Gutierrez-Hellin J. The OMNIVEG STUDY: Health outcomes of shifting from a traditional to a vegan Mediterranean diet in healthy men. A controlled crossover trial. Nutr Metab Cardiovasc Dis. 2024 Dec;34(12):2680-2689. doi: 10.1016/j.numecd.2024.08.008. Epub 2024 Aug 23.
- 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.
Miguel López Moreno, Phd principal investigator
Universidad Francisco de Vitoria
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Vegan diet and Mediterranean diet in people with Cardiometabolic Syndrome, run by Universidad Francisco de Vitoria at 1 site in Spain.
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 6 inclusion and 2 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 28 Nov 2023. 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 Spain. 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?
Cardiorespiratory fitness (time frame: 4 weeks). The study lists 7 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 NCT06008886, which also lists 2 linked publications.
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 28 Nov 2023.