Onion, Cardiovascular Risk Markers and Gene Expression — M197  

Blood Pressure Clinical Trial

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

Status Completed

Clinical Trial Summary

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)

Clinical Trial Description

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. ;

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Crossover Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Prevention

Related Conditions & MeSH terms

• Blood Pressure
• Coagulation Delay

• NCT number: NCT02449590
• Study type: Interventional
• Source: University of Copenhagen
• Status: Completed
• Phase: N/A
• Start date: August 2008
• Completion date: April 2009