Onion, Cardiovascular Risk Markers and Gene Expression (M197)

Professor Lars Ove Dragsted

Status: Completed

Conditions: Coagulation Delay; Blood Pressure

Treatments: Dietary Supplement: Placebo; Dietary Supplement: Onion powder

Study type: Interventional

Funder types: Other

Identifiers

NCT02449590

M197

Details and patient eligibility

About

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)

Full 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.

Enrollment: 10 patients

Sex: All

Ages: 18 to 70 years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Quadruple Blind

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10 participants in 2 patient groups, including a placebo group

Onion powder

Active Comparator group

Description:

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.

Treatment:

Dietary Supplement: Onion powder

Placebo

Placebo Comparator group

Description:

Hot meals (1 potato soup and 1 meatball-meal daily)containing 8.5 g sucrose and 2 g soy protein instead of onion powder

Treatment:

Dietary Supplement: Placebo