Prediabetes, Hypertension
Conditions
Brief summary
In this double-blind parallel placebo controlled intervention study the effects of 3 times daily 500 mg gamma-aminobutyric acid (GABA) supplementation on glucose tolerance and cardiovascular health will be assessed in prediabetics.
Interventions
DIETARY_SUPPLEMENTGABA
The dietary supplement GABA will be taken orally 3 times daily, before each main meal
OTHERPlacebo
Gelatin capsule containing powdered cellulose
Sponsors
Nunhems
Agrico Research
Avebe
Wageningen University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Intervention model description
Randomized placebo controlled double blind parallel study design
Eligibility
Sex/Gender
ALL
Age
50 Years to 70 Years
Healthy volunteers
Yes
Inclusion criteria
* Age between 50 and 70 * BMI higher or equal to 27 kg/m2 * Impaired fasting glucose (fasting glucose ≥ 6.1 and ≤ 6.9 mmol/L) or/and * Impaired glucose tolerance (glucose levels ≥ 7.8 and ≤ 11.1 mmol/L, 2-hours after an OGTT or/and glucose levels ≥8.6 mmol/L, 1-hour after an OGTT)
Exclusion criteria
* Has been diagnosed with diabetes * Having other conditions, like liver, pancreatic, cardiovascular, gastro-intestinal or endocrine diseases, that could influence the study results * Use of medications or supplements that could influence the study results * Sensitive to medical skin adhesives * More than 5kg weight change in the past 12 weeks * Excessive alcohol consumption (\>21 glasses/week for men and \>14 glasses/week for women on average) * Being an employee of Wageningen University, division Human Nutrition and Health * Currently a research subject in other research
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Postprandial glycaemic response during a 2 hour oral glucose tolerance test (OGTT) | blood will be drawn at baseline and after 30, 60 and 120 minutes, before and after the 12 weeks intervention | A 2 hour oral glucose tolerance test with 75gr glucose |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Plasma free fatty acids | before and after the 12 weeks intervention | — |
| HbA1c | before and after the 12 weeks intervention | — |
| Glucose variability | 5 days during which they eat their habitual diet, before and after the 12 weeks intervention | The participants wear a flash glucose monitoring sensor with which their interstitial glucose is measured every 15 minutes. |
| Blood pressure | Dynamic measurement: 24 hours, before and after the 12 weeks intervention | Single measurement and a dynamic measurement: * Mean day systolic and diastolic blood pressure * Mean night systolic and diastolic blood pressure * Time below or above 120/80 mmHg |
| Heart rate | before and after the 12 weeks intervention | — |
| Concentrion of markers of inflammation in blood | before and after the 12 weeks intervention | C-reactive protein and cytokines like IL-6 and TNF-alpha |
| Concentration of triglycerides in blood | before and after the 12 weeks intervention | — |
| Concentration of LDL and HDL cholesterol in blood | before and after the 12 weeks intervention | — |
| Postprandial insulin and glucagon response during a 2 hour OGTT, | blood will be drawn at baseline and after 30, 60 and 120 minutes, before and after the 12 weeks intervention | A 2 hour oral glucose tolerance test with 75gr glucose |
| Acute effects of GABA on postprandial glucose | 2 hours, after a single administration of 500 mg GABA | Assessed with an OGTT during which interstitial glucose is measured with flash glucose monitoring |
| Acute effects of GABA on blood pressure | for 24 hours during which GABA is taken 3 times, each time before the main meal | Assessed with an ambulatory blood pressure monitor |
| Sleep quality | before and after the 12 weeks intervention | Pittsburgh Sleep Quality Index (PSQI) questionnaire, the outcome is a global PSQI score (range: 0-21), with higher scores indicating poorer sleep quality. |
| Feelings of depression | before and after the 12 weeks intervention | Patient Health Questionnaire (PHQ-9), the higher the score the more depressed a person is. |
| Feelings of anxiety | before and after the 12 weeks intervention | General Anxiety Disorder (GAD-7) questionnaire, the higher the score, the more anxious a person is. |
| Plasma GABA concentration | before and after the 12 weeks intervention | — |
| Plasma glutamate concentration | before and after the 12 weeks intervention | — |
| Concentration of ALAT and ASAT in blood | before and after the 12 weeks intervention | — |
Countries
Netherlands
Outcome results
None listed