HealthyNCT03849677
Uric Acid Metabolism, Endothelial Function and Oxidative Stress in Vegans and Omnivores.
An observational study of Healthy and Diet Modification, run by Erasme University Hospital at 1 site in Belgium.
Trial summary
50 vegans and 50 omnivores will be recruited at the Erasme Hospital, Brussels. Hypothesis Relative induced-hyperuricemia by the vegan diet is not associated with impaired endothelial function if vitamin B12 and folic acid levels are normal. Read more about this study
- Who is it for?
- Ages 20 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy, Diet Modification
- What is being tested?
- Endothelial function and inflammation
- How many people
- 103 participants
- Where
- 1 siteBelgium
- Study dates
- 10 Mar 2019to 20 Jun 2020
- Phase
- Observational
- 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 20 to 50 years
- All sexes
- Healthy volunteers accepted
- Adult
Study population: Participants will be recruited upon invitation on social network mainly.
Who may be able to join
- Vegan or omnivore diet for at least one year (matched for age, gender, BMI, socio-economic status and weight)
- Healthy
Who cannot join
- Smoking
- Chronic treatment
- No allowed drugs taking
- Excessive alcohol consumption
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Differential Analysis of Uric Acid Metabolism, Endothelial Function, Oxidative Stress and Cardiovascular Parameters in Vegans and Omnivores.
50 vegans and 50 omnivores will be recruited at the Erasme Hospital, Brussels.
Hypothesis
- Relative induced-hyperuricemia by the vegan diet is not associated with impaired endothelial function if vitamin B12 and folic acid levels are normal.
- Quantification of xanthine oxidoreductase (XOR) isoforms varies according to the diet. Omnivores present more xanthine oxidase (XO) than vegans in which the xanthine dehydrogenase (XD) isoform is more prevalent.
- The vegan group has more favorable oxidant, metabolic and inflammatory profiles than the omnivore group.
Read the detailed description
Non-meat eaters rise widely worldwide. This choice answers ideological, ecological or health concerns. Several vegetarian diets exist and the vegan diet is the most restricted one as it excludes all animal products, eggs and dairy.
Beside benefits on health and particularly on the cardiovascular system (blood pressure, weight, lipid profile), some authors described less favorable lipid and oxidative profiles and others described an impairment in endothelial function markers in 'vegans'. These effects were attributed to low vitamin B12 and folate levels and high homocystein levels. However, vitamin B12 supplementation improved these parameters. Epidemiological studies also showed that 'vegans' disclose higher uric acid levels than other vegetarians or omnivores. Uric acid acts as an antioxidant in the plasma but can be deleterious for vascular cells leading to endothelial dysfunction. The main enzyme involved in uric acid metabolism is xanthine oxidoreductase which exists under two interconvertible isoforms. Xanthine dehydrogenase is the main form and uses nicotinamide adenine dinucleotide (NAD+) as electron acceptor and does not produce reactive oxygen species (ROS). In contrast, the other isoform xanthine oxidase uses oxygen as an electron acceptor and produces reactive oxygen species (ROS). The investigators wish to test the hypothesis that it is not uric acid per se, but which isoform of xanthine oxidoreductase which alters endothelial function. This is why the investigators wish to determine if regular 'vegans' (with normal vitamin B12 and folate levels) disclose increased uric acid levels in the presence of a reduced inflammation, oxidative stress and improved endothelial function, as compared to matched 'omnivores'.
50 vegans and 50 omnivores will be recruited at the Erasme Hospital, Brussels.
Hypothesis
- Relative induced-hyperuricemia by the vegan diet is not associated with impaired endothelial function if vitamin B12 and folic acid levels are normal.
- Quantification of oxidoreductase (XOR) isoforms varies according to the diet. Omnivores present more xanthine oxidase (XO) than vegans in which the xanthine dehydrogenase (XD) isoform is more prevalent.
- The vegan group has more favorable oxidant, metabolic and inflammatory profiles than the omnivore group.
- Conditions
- Healthy, Diet Modification
- Being tested
- Endothelial function and inflammation
- Keywords
- uric acid, hemodynamic parameters, endothelial function, oxidative stress and inflammation, vegan, omnivore
- Medical subject headings
- Inflammation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Endothelial function and inflammationOther
Analysis of endothelial function, oxidative stress
| Study group | Role | What they receive |
|---|---|---|
| Omnivore | Not described Receives: Other: Endothelial function and inflammation | |
| Vegan | Not described Receives: Other: Endothelial function and inflammation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Measure of the perfusion of the microcirculation of the skin
Endothelial function assessment will be performed through analyse of the perfusion of the microcirculation of the skin in the forearm will be assessed by means of a laser Doppler imager and iontophoresis of acetylcholine and sodium nipride. Heating-induced hyperemia will be assessed after iontophoresis of inhibitor of NO synthase and saline. Units are perfusion unit.
Iontophoresis is a non-invasive tool which permits to infuse molecules in the first micrometers of the skin. The used molecules are vasodilative, saline or NO synthase inhibitor.
Measured: 2 hours
Secondary outcomes (18)
Concentration of Uric acid
Uric acid (mg/dL or SI)
Measured: 2 hours
Concentration of xanthine oxidase and xanthine dehydrogenase in blood
western blot
Measured: 2 hours
Measure of hemoglobin
g/l
Measured: 2 hours
Measure of white blood cells, red blood cells and platelets
cells/µl of blood
Measured: 2 hours
Measure of urea, creatinine, bilirubin, albumine, prealbumin, LDL, HDL, lp(a), total cholesterol, triglyceride, apolipoprotein A and B
mg/dl
Measured: 2 hours
Measure of glycemia, vitamine and iron status (B3, B6, B12, C, D, E, B9, Zn, Cu, Selenium, iron, ferritin), c-reactive protein, homocystein
mg/dl
Measured: 2 hours
Measure of sodium, potassium, chlore, phosphor, calcium, magnesium, HbA1c, omega 3 et 6
mmol/l
Measured: 2 hours
Measure of glomerular filtration rate
ml/min
Measured: 2 hours
Measure of gamma-glutamyltransferase, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, creatin phosphokinase, insulin, TSH
u/l
Measured: 2 hours
Measure of allantoin, homocitrulline/lysine, chloro-tyrosine/tyrosine, Il-8, myeloperoxidase
Mass spectrometry and Elisa Kits
Measured: 2 hours
Measure of renin, aldosterone, angiotensin 2, angiotensin converting enzyme
Measured: 2 hours
Measure of main proteomes and metabolomes in cells incubated with sera from participants
Sera will be used for cell cultures. Theses cells will be lysed and used to analyse and compare the different proteomes / metabolomes according to the groups. We will be able to understand which protein groups are reduced or enhanced according to the diet.
Measured: 2 hours
Measure of blood pressure
Systolic and diastolic blood pressure
Measured: 2 hours
Measure of baroreflex sensitivity
finometer
Measured: 2 hours
Measure of heart rate
finometer
Measured: 2 hours
Measure of augmentation index
Assessment of the arterial stiffness
Measured: 2 hours
Measure of pulse wave velocity
Assessment of the arterial stiffness
Measured: 2 hours
Diet questionary
Diet History Questionnaire third version provides estimation of one year consumption of proteins, carbohydrates, lipids, micronutrient and vitamines
Measured: 2 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Feb 2019
- Study start10 Mar 2019
- Primary completion30 Mar 2020
- Study completion20 Jun 2020
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies 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
- Observational
- Observational model
- Case-control
- Time perspective
- Cross-sectional
- Enrolment
- 103 participants (actual)
Sponsor and investigators
- Lead sponsor
- Erasme University Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- Fonds National de la Recherche Scientifique, Fonds Erasme, Fonds pour la chirurgie cardiaque
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03849677
- Sponsor's protocol ID
- 34735921
- Status last verified
- Jun 2020
- First submitted
- 6 Feb 2019
- Last updated
- 1 Jul 2020
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 1 Jul 2020. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Differential Analysis of Uric Acid Metabolism, Endothelial Function, Oxidative Stress and Cardiovascular Parameters in Vegans and Omnivores.
- ClinicalTrials.gov ID
- NCT03849677
- Acronym / sponsor ID
- 34735921
- Conditions
- Healthy, Diet Modification
- Keywords
- uric acid, hemodynamic parameters, endothelial function, oxidative stress and inflammation, vegan, omnivore
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 103 participants (actual)
- Lead sponsor
- Erasme University HospitalUniversity, hospital or other
- Collaborators
- Fonds National de la Recherche Scientifique, Fonds Erasme, Fonds pour la chirurgie cardiaque
- Study start
- 10 Mar 2019 (actual)
- Primary completion
- 30 Mar 2020 (actual)
- Study completion
- 20 Jun 2020 (actual)
- First posted
- 21 Feb 2019 (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.
50 vegans and 50 omnivores will be recruited at the Erasme Hospital, Brussels.
Hypothesis
- Relative induced-hyperuricemia by the vegan diet is not associated with impaired endothelial function if vitamin B12 and folic acid levels are normal.
- Quantification of xanthine oxidoreductase (XOR) isoforms varies according to the diet. Omnivores present more xanthine oxidase (XO) than vegans in which the xanthine dehydrogenase (XD) isoform is more prevalent.
- The vegan group has more favorable oxidant, metabolic and inflammatory profiles than the omnivore group.
Detailed description
Non-meat eaters rise widely worldwide. This choice answers ideological, ecological or health concerns. Several vegetarian diets exist and the vegan diet is the most restricted one as it excludes all animal products, eggs and dairy.
Beside benefits on health and particularly on the cardiovascular system (blood pressure, weight, lipid profile), some authors described less favorable lipid and oxidative profiles and others described an impairment in endothelial function markers in 'vegans'. These effects were attributed to low vitamin B12 and folate levels and high homocystein levels. However, vitamin B12 supplementation improved these parameters. Epidemiological studies also showed that 'vegans' disclose higher uric acid levels than other vegetarians or omnivores. Uric acid acts as an antioxidant in the plasma but can be deleterious for vascular cells leading to endothelial dysfunction. The main enzyme involved in uric acid metabolism is xanthine oxidoreductase which exists under two interconvertible isoforms. Xanthine dehydrogenase is the main form and uses nicotinamide adenine dinucleotide (NAD+) as electron acceptor and does not produce reactive oxygen species (ROS). In contrast, the other isoform xanthine oxidase uses oxygen as an electron acceptor and produces reactive oxygen species (ROS). The investigators wish to test the hypothesis that it is not uric acid per se, but which isoform of xanthine oxidoreductase which alters endothelial function. This is why the investigators wish to determine if regular 'vegans' (with normal vitamin B12 and folate levels) disclose increased uric acid levels in the presence of a reduced inflammation, oxidative stress and improved endothelial function, as compared to matched 'omnivores'.
50 vegans and 50 omnivores will be recruited at the Erasme Hospital, Brussels.
Hypothesis
- Relative induced-hyperuricemia by the vegan diet is not associated with impaired endothelial function if vitamin B12 and folic acid levels are normal.
- Quantification of oxidoreductase (XOR) isoforms varies according to the diet. Omnivores present more xanthine oxidase (XO) than vegans in which the xanthine dehydrogenase (XD) isoform is more prevalent.
- The vegan group has more favorable oxidant, metabolic and inflammatory profiles than the omnivore group.
Study design
- Observational model
- Case-control
- Time perspective
- Cross-sectional
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Omnivore | – | Other: Endothelial function and inflammation |
| Vegan | – | Other: Endothelial function and inflammation |
Who may qualify
- Ages
- 20 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- Participants will be recruited upon invitation on social network mainly.
Key inclusion criteria (2 listed)
- Vegan or omnivore diet for at least one year (matched for age, gender, BMI, socio-economic status and weight)
- Healthy
Key exclusion criteria (4 listed)
- Smoking
- Chronic treatment
- No allowed drugs taking
- Excessive alcohol consumption
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 |
|---|---|---|
| Endothelial function and inflammationAnalysis of endothelial function, oxidative stress | Other | Omnivore, Vegan |
Primary outcome
Measure of the perfusion of the microcirculation of the skin
Time frame: 2 hours
Endothelial function assessment will be performed through analyse of the perfusion of the microcirculation of the skin in the forearm will be assessed by means of a laser Doppler imager and iontophoresis of acetylcholine and sodium nipride. Heating-induced hyperemia will be assessed after iontophoresis of inhibitor of NO synthase and saline. Units are perfusion unit. Iontophoresis is a non-invasive tool which permits to infuse molecules in the first micrometers of the skin. The used molecules are vasodilative, saline or NO synthase inhibitor.
18 secondary outcomes
Concentration of Uric acid
Time frame: 2 hours
Concentration of xanthine oxidase and xanthine dehydrogenase in blood
Time frame: 2 hours
Measure of hemoglobin
Time frame: 2 hours
Measure of white blood cells, red blood cells and platelets
Time frame: 2 hours
Measure of urea, creatinine, bilirubin, albumine, prealbumin, LDL, HDL, lp(a), total cholesterol, triglyceride, apolipoprotein A and B
Time frame: 2 hours
Measure of glycemia, vitamine and iron status (B3, B6, B12, C, D, E, B9, Zn, Cu, Selenium, iron, ferritin), c-reactive protein, homocystein
Time frame: 2 hours
Measure of sodium, potassium, chlore, phosphor, calcium, magnesium, HbA1c, omega 3 et 6
Time frame: 2 hours
Measure of glomerular filtration rate
Time frame: 2 hours
Measure of gamma-glutamyltransferase, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, creatin phosphokinase, insulin, TSH
Time frame: 2 hours
Measure of allantoin, homocitrulline/lysine, chloro-tyrosine/tyrosine, Il-8, myeloperoxidase
Time frame: 2 hours
Measure of renin, aldosterone, angiotensin 2, angiotensin converting enzyme
Time frame: 2 hours
Measure of main proteomes and metabolomes in cells incubated with sera from participants
Time frame: 2 hours
Measure of blood pressure
Time frame: 2 hours
Measure of baroreflex sensitivity
Time frame: 2 hours
Measure of heart rate
Time frame: 2 hours
Measure of augmentation index
Time frame: 2 hours
Measure of pulse wave velocity
Time frame: 2 hours
Diet questionary
Time frame: 2 hours
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 1 Jul 2020.
- 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.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Healthy and Diet Modification, run by Erasme University Hospital at 1 site in Belgium.
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 2 inclusion and 4 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 1 Jul 2020. 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 Belgium. 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?
Measure of the perfusion of the microcirculation of the skin (time frame: 2 hours). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 1 Jul 2020.