Onion, Cardiovascular Risk Markers and Gene Expression

Study Overview
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Brief Summary
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AIMS: The aims are to investigate whether: Increased intake of onion (powder) affects plasma lipid profile, blood pressure, indices of insulin sensitivity and blood coagulation. Increased intake of onion (powder) affects the expression/activity of enzymes in the defence against foreign substances, e.g. reactive oxygen species, and whether polymorphisms in some of the involved genes may modulate the effect. Polymorphisms involved in the metabolism/effect of bioactive components in onion modulate the excretion of metabolites or modulate some of the outcome variables in the study. Other aims are to try to identify biomarkers for onion consumption in plasma, urine and feces and to investigate whether onion affects the secretion of fat and bile acids. HYPOTHESES: The investigators hypothesize that: 2 weeks of increased onion intake will improve the plasma lipid profile 2 weeks of increased onion intake will increase the metabolism of potentially harmful substances (such as ROS and free radicals) through a change in the expression or activity of certain enzymes. That these effects are modulated by common gene variants (polymorphisms)

Detailed Description
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In a randomized controlled crossover design, participants will receive 2 daily meals with or without onion powder for 2 weeks. Between the two 2-week period is a 4-week wash-out period. One week before and during each intervention period, the participants will be instructed to avoid consumption of onion, garlic and all foodstuffs containing the same bioactive components (polyphenols, sulfur-molecules)as in onion. This includes a number of vegetables and fruits, condiments, tea, chocolate, red wine etc. Fasting blood samples will be drawn before and after (on 2 separate days) each intervention period, where also weight and blood pressure are measured. Participants will collect 24-hour urine and feces samples twice before and at completion of each intervention period. After the fasting blood sampling on the first blood sampling day in each period, participants will receive a test meal (with 10 g onion powder or placebo, i.e. 8.5 g sucrose+ 2 g soy protein isolate). The acute effects will be studied by blood sampling and urine sampling 0, 2, 4 and 24 hours after the test meal.

Official Title
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The Effects of Onion on Plasma Lipoproteins, Blood Pressure and Gene Expression in Overweight Humans - a Double-blinded, Randomized Cross-over Study

Conditions
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Blood Pressure, Coagulation Delay

Intervention / Treatment
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* Dietary Supplement: Onion powder
* Dietary Supplement: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy BMI 25-40 No daily medication (except thyroid hormone, stomach acid lowering drugs, mild blood pressure lowering drugs and anti-depressants) Not strenuous exercise >10 hours/week No blood donation 3 months before or during the study Exclusion Criteria: Diabetes, CVD, hepatitis, HIV/AIDS Cancer or cancer treatment within last 6 months Smoking Simultaneous participation in other research projects

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Onion powder<br>Initial test meal contained 20g freeze dried onion powder in hot meals (1 potato soup and 1 meatball-meal daily). Subsequent daily meals contained 20g onion powder in the same meal formats. | Dietary Supplement: Onion powder<br>* Hot meals with onion powder; 10 g/day onion powder corresponding to 100 g/day fresh onion in meals with potato and beef Intervention period 14 days.<br>|
| Placebo Comparator: Placebo<br>Hot meals (1 potato soup and 1 meatball-meal daily)containing 8.5 g sucrose and 2 g soy protein instead of onion powder | Dietary Supplement: Placebo<br>* Hot meals without onion powder; Control meal with potato, beef, soy protein, and sucrose to match macronutrient composition of active treatment<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in blood pressure from baseline to two weeks | Measured by a standard arm cuff by a trained bioanalyst | baseline to two weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in waist-to-hip circumference ratio | Measured manually by a trained bioanalyst | Change from baseline to two weeks | 
| Change in fecal microbiota profile | RFLP of 16S cDNA | change from baseline to two weeks | 
| Change in total cholesterol | Total plasma cholesterol in lipoproteins measured by a clinical chemistry kit | change from baseline to 2, 4, and 24 hours and 2 weeks | 
| Change in HDL cholesterol | High density Lipoprotein Cholesterol in plasma measured by an immunokit | change from baseline to 2, 4, and 24 hours and 2 weeks | 
| Change in plasma triacylglycerides | Triacylglycerides in plasma measured by an immunokit | change from baseline to 2, 4, and 24 hours and 2 weeks | 
| Change in blood coagulation parameters | thromboelastography measurements, fibrinogen etc. in plasma | 0-4 hours | 
| Change in whole-blood hematocrit | hematocrit by standard clinical chemistry | 0-14 days | 
| Change in whole-blood haemoglobin concentration | haemoglobin concentration by standard clinical chemistry | 0-14 days | 
| Change in body weight | Measured in triplicate on a calibrated balance | 0-14 days | 
| Change in serum VCAM-1 | Determined with standard kits | 0-14 days | 
| Change in serum IL-6 | Determined with standard kit | 0-14 days | 
| Change in serum TNF-alpha | Determined with standard kit | 0-14 days | 
| Change in faecal metabolic profiles | Untargeted metabolomics by LC-QTOF profiling of polar metabolites | 0-14 days | 
| Change in faecal pH | pH by a pH-meter in a 50% aqueous fecal slurry | 0-14 days | 
| Change in faecal bile acids | bile acids measured by LC-TQD | 0-14 days | 
| Change in urine metabolomic profiles | Untargeted metabolomics by LC-QTOF profiling of polar metabolites | 0-14 days | 
| Change in urine pH | pH by a pH-meter | 0-14 days | 
| Change in plasma insulin (multivariate ANOVA) | Insulin measured at baseline before meals and at 2, 4 and 24 hours, 2, 7 and 14 days after the start of intervention. | 0-14 days | 
| Change in plasma glucose (multivariate ANOVA) | Glucose measured at baseline before meals and at 2, 4 and 24 hours, 2, 7 and 14 days after the start of intervention. | 0-14 days | 
| Change in HOMA | Change in HOMA measured at baseline before meals and at 14 days after the start of intervention. | 0-14 days | 
| Change in ISI240 (Matsuda insulin sensitivity index 0-240) | Change in ISI240 measured from 0-240 minutes after the first test meal. | 0-240 minutes | 
| Change in erythrocyte Glutathione Reductase | Measured by automated colorimetric assays | 0-2 weeks | 
| Change in erythrocyte superoxide dismutase | Measured by automated colorimetric assays | 0-2 weeks | 
| Change in erythrocyte catalase | Measured by automated colorimetric assays | 0-2 weeks | 
| Change in erythrocyte glutathione peroxidase | Measured by automated colorimetric assays | 0-2 weeks | 
| Change in plasma untargeted metabolic profile | LC-QTOF profiling of polar metabolites and polar lipids | 0-2 weeks | 
| Change from baseline in leucocyte gene expression profile | Selected genes by RT-PCR | 0, 2, 4 and 24 hours and 2 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Onion, Cardiovascular disease, metabolomics, Gene expression, Biomarker