To study the effects of flaxseed oil, rich in ALA on 24h-ambulatory mean arterial pressure (MAP) in men and women with high-normal blood pressure and mild hypertension compared to high oleic sunflower oil, poor in ALA.
ID
Source
Brief title
Condition
- Lipid metabolism disorders
- Vascular hypertensive disorders
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
The main study parameter is the change in 24h-ambulatory mean arterial pressure
(MAP)
Secondary outcome
The secondary objectives are to study the effects of flaxseed oil on 1) night,
day and early morning 24h-ambulatory MAP, 2) systolic, diastolic and MAP office
blood pressure, 3) postprandial flow mediated dilatation (FMD) and 4) the
fatty-acid profile of plasma phospholipids
Background summary
Increased intakes of n-3 long chain polyunsaturated fatty acids eicosapentanoic
acid (EPA) and docosahexaenoic acid (DHA), mainly found in fatty fish, are
recommended for the prevention of coronary heart disease. Alpha-linolenic acid
(ALA, C18:3n-3) is the most common vegetable-oil based n-3 fatty acid. Evidence
exists that ALA supplementation can also have a protective effect on the
development on cardiovascular disease, but may exert its cardioprotective
effects through different routes. The benefit may (partly) be due to blood
pressure lowering. However, evidence for beneficial effects of ALA on blood
pressure is conflicting. Therefore, we propose to investigate the effect of
flaxseed oil, high in ALA, using a study powered on 24-hour blood pressure, in
a population with high normal blood pressure and mild hypertension.
Study objective
To study the effects of flaxseed oil, rich in ALA on 24h-ambulatory mean
arterial pressure (MAP) in men and women with high-normal blood pressure and
mild hypertension compared to high oleic sunflower oil, poor in ALA.
Study design
Using a double blind randomized, placebo-controlled parallel design, subjects
will receive at random daily 10 g of flaxseed oil or a high-oleic acid
sunflower oil (HOSF) as control for twelve weeks, with a run-in period of 14
days in advance.
Intervention
During the run-in period, subjects will receive daily 10 g of palm super olein
oil. During the intervention period subjects receive either 10 ml of high oleic
sunflower oil or flaxseed oil. All oils are provided in bottles of 5 g, on will
be consumed at breakfast or lunch and one at dinner.
Study burden and risks
Before the start of the study subjects will be screened to determine
eligibility during one 15 and one 10 min visit. During these visits, body
weight, height and blood pressure will be measured and a blood sample (5.5 mL)
will be drawn by means of venapunction.
During the run-in period of two weeks, subjects will receive palm super olein
oil and during the intervention period of twelve weeks they will receive at
random, HOSF or flaxseed oil. On six occasions a fasting blood sample will be
drawn (with a total of 50 mL spread over the six visits), body weight and blood
pressure will be measured. In addition, during week 2 and 6, a retinal image
will be taken and pulse wave velocity measurements will be performed to assess
vascular function. Also 24-h blood presseure measurements will be performed,
this can disturb daily activities because they have to be interrupted when the
measurement is performed.
A subset of 40 subjects will participate in a postprandial test. An intravenous
cannula will be inserted in an antecubital vein. Before and after meal
consumption, nine blood samples (67.5 mL) will be drawn over 4.5 hours and flow
mediated dialation (FMD) will be measured.
All subjects will be asked to fill out a food frequency questionnaire two times
and to keep a study-diary throughout study. On rare occasions, blood sampling
might cause bruises or hematoma. Total time investment for the subjects will be
approximately 6.5 hours and an extra 4.5 hours if they participate in the
postprandial test.
Universiteitsingel 50
Maastricht 6229 ER
NL
Universiteitsingel 50
Maastricht 6229 ER
NL
Listed location countries
Age
Inclusion criteria
- Aged between 40-70 years
- Quetelet-index between 25-35 kg/m2
- High-normal blood pressure or stage I hypertension
- Mean serum total cholesterol < 8.0 mmol/L
- Mean serum triacylglycerol < 4.5 mmol/L
- Mean plasma glucose < 7.0 mmol/L
Exclusion criteria
- Unstable body weight (weight gain or loss >2 kg in the past 3 months)
- Use of antihypertensive or anticoagulant medication
- Indication for treatment with cholesterol-lowering drugs according to the Dutch Cholesterol Consensus
- Usage of non-steroidal anti-inflammatory drugs (aspirin, ibuprofen, naproxen) and not able or willing to stop taking them from at least 4 weeks prior to the study
- Use of medication or a diet known to affect serum lipid or glucose metabolism
- Women taking oral contraceptives or estrogen replacement therapy
- Women lactating, pregnant or intend to become pregnant during study
- Active cardiovascular disease like congestive heart failure or recent (<6 months) event (acute myocardial infarction, cerebro vascular accident)
- Severe medical conditions that might interfere with the study such as diabetes mellitus, epilepsy, asthma, chronic obstructive pulmonary disease, inflammatory bowel diseases and rheumatoid arthritis
- Smoking
- Abuse of drugs
- More than 21 alcohol consumptions per week for men and 14 consumptions for women
- Reported intense sporting activities > 10 h/w
- Not possible or difficult to venipuncture as evidenced during the screening visits
- Use of an investigational product within the previous 30 days
- Not willing to stop the consumption of vitamin supplements, fish oil capsules or products rich in plant stanol or sterol esters 3 weeks before the start of the study
- Not willing to give up being a blood donor (or having donated blood) from 8 weeks before the start of the study and during the study
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL47452.068.13 |