To investigate whether the intake of a single dose of nitrate-rich beetroot juice or a flavonoid-rich black tea causes an increase of post-prandial muscle blood flow in obese insulin resistant subjects
ID
Source
Brief title
Condition
- Other condition
Synonym
Health condition
obesitas
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
Peripheral vascular resistance after a 75 gr glucose load combined with
water/tea/beetroot juice, where vascular resistance is calculated as the
product of blood flow as measured by venous occlusion plethysmography and
arterial blood pressure by the Finapress (in mmHg/100 mL tissue/min). The
area-under-the-curve of the peripheral vascular resistance in the forearm and
leg is calculated up to 3 h after the glucose load.
Secondary outcome
NA
Background summary
Skeletal muscle is the principal tissue responsible for insulin-stimulated
glucose disposal and therefore plays an important role in the postprandial
regulation of glucose levels. Impaired glucose transport in skeletal muscle,
such as present with obesity, leads to impaired whole body glucose uptake.
Indeed, obesity is associated with an impaired postprandial increase in
skeletal muscle blood flow. The lower postprandial blood flow may contribute to
the impaired glucose homeostasis. Restoring glucose disposal may therefore be
induced by improving skeletal muscle blood flow and vascular function. Based on
in vitro and in vivo, previous studies found that flavonoid-rich and
nitrate-rich food products improve vascular function. Therefore, these food
products may improve postprandial blood flow responses in obese subjects.
In the present study, muscle perfusion will be studied before and after an oral
glucose challenge following a fasting period, which will induce an
insulin-dependent increase in muscle blood flow and glucose metabolism. Based
on data from previous studies, this physiological response is blunted in obese
subjects, and we expect these responses to be restored when the glucose load is
combined with tea or beetroot juice.
Study objective
To investigate whether the intake of a single dose of nitrate-rich beetroot
juice or a flavonoid-rich black tea causes an increase of post-prandial muscle
blood flow in obese insulin resistant subjects
Study design
randomised, placebo-controlled, cross-over study
Study burden and risks
The flavonoid-rich tea fraction is derived from ordinary brewed black tea and
thus considered harmless. The second intervention is Beet-It beetroot juice
(James White Drinks Ltd.), which is a commercially available drink and also
considered harmless.
Prior to the 3 visit days, subjects have fasted since the evening before the
visit. As all subjects are considered to be healthy, we expect no health
problems or problems with the overnight fast period. All vascular function
measurements are non-invasive. For blood analyses, repeated venous blood
samples (7 X 10 mL) will be taken from an intra-venous catheter in the
forearm. Insertion of the catheter is associated with a 5% risk for
haemorrhage, which will result in a full recovery within 2 weeks. Subjects will
ingest 75 grams of glucose, which is the amount that is used in the very widely
applied Oral Glucose Tolerance Test, and therefore not expected to cause any
harm to the subject. Participants do not directly benefit from study
participation.
Olivier van Noortlaan 120
Vlaardingen 3133 AT
NL
Olivier van Noortlaan 120
Vlaardingen 3133 AT
NL
Listed location countries
Age
Inclusion criteria
- Male sex
- Aged 30-70 years
- Obesity (>30 kg/m2)
- insulin resistance as fasting glucose levels >6.1 mmol/L
- Reported intense sport activities <=10 h/w
- Reported alcohol consumption <=28 units/w
- Agreeing to be informed about medically relevant personal test-results by a physician
- Signed Informed consent
- Currently not smoking and being a non-smoker for at least 3 months prior to the start of the study
Exclusion criteria
- BMI >=40 kg/m2
- Presence of cardiovascular disease
- Presence of sudden cardiac death in a 1st degree relative at an age <50 years
- Presence of diabetes mellitus type 2
- Regular tea drinker (> 2 cups per day)29
- Prescribed medical treatment that may affect the cardiovascular system
- Reported use of any medically- or self-prescribed diet
- Reported weight loss or gain >10% during a period of 6 months prior to the study
- Subjects who participated in studies with a drug and/or nutritional intervention and without risks for carry-over effects are excluded for 1 month from participation in this study
- Reported participation in night shift work two weeks prior to the study or during the study (defined as working between midnight and 6.00 am)
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 | NL41626.091.12 |