Polycystic Ovary Syndrome (PCOS), overweight/obesity and insulin resistance Nutritional, Metabolic, Endocrine
Conditions
Interventions
The study consisted of two intervention treatments:
1. Placebo treatment - placebo tablets
2. Active treatment (polyphenol supplements) - Green Tea extract (GTE) tablet
Sponsors
Medical Research Council - Human Nutrition Research (UK)
Eligibility
Sex/Gender
Female
Inclusion criteria
Inclusion criteria: 1. Otherwise healthy 2. Pre-menopausal, overweight or obese women (BMI = 25 kg/m2) 3. Aged16-45 years 4. With PCOS and insulin resistance (fasting insulin = 50 pmol/L)
Exclusion criteria
Exclusion criteria: 1. Smoking 2. History of substance abuse or alcohol consumption >14 units per week 3. Allergy or intolerance to the study supplements and/or foods 4. Professional athletes or those with self-reported high physical activity 5. Chronic, acute or active metabolic (including type 1 and type 2 diabetes mellitus) and inflammatory conditions, haematological disorders, or any other systemic illness of renal, hepatic or gastrointestinal origin 6. Active cancer or diagnosis of malignancy within the last five years 7. Major surgical operations interfering with the study outcomes within three months of screening 8. Medical treatment with the following agents: weight reduction medicines, insulin sensitizers, hormonal therapy, antihypertensive medicines, anti-dyslipidaemic agents, nitrate-derived agents, psychiatric drugs (only excluded if dose had been started/changed in the previous six months) or any other medication known to affect glucose/insulin metabolism, vascular/endothelial function, gastrointestinal system or central nervous system 9. Weight change > 10% over the last six months 10. Endocrine disorders such as adrenal hyperplasia, hyperprolactinaemia, Cushing?s syndrome, androgenic tumours, late onset of 21-hydroxylase deficiency, abnormal thyroid function or any other ovarian, adrenal or pituitary disorder not associated with PCOS 11. Pregnant, lactating, contemplating pregnancy or undergoing treatment to achieve pregnancy 12. Regular consumption of micronutrient and/or herbal and/or polyphenol supplements known to have an impact on insulin sensitivity/secretion and/or vascular/endothelial function
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Insulin sensitivity and secretion were measured at baseline (week 0), post-placebo (week 8) and post-intervention (week 16) time points via the Oral Dose Intravenous Labelled Glucose Experiment (ODILE) protocol. The ODILE protocol is similar to the Oral Glucose Tolerance Test (OGTT), but it is modified by the addition of an intravenous dose of [1]-13C-glucose (labelled glucose) administered 45 minutes after the oral glucose dose was consumed (40 blood samples are taken over a 4-hour and 45 minute period). Gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) is used for isotopic composition and the results are interpreted using a stable-label two compartment minimal model (2CMM). This mathematical modelling allows for the determination of glucose effectiveness and insulin sensitivity parameters. Insulin and C-peptide data obtained from the same protocol were also modelled to obtain information about insulin secretion. | — |
Secondary
| Measure | Time frame |
|---|---|
| 1. Nitric oxide production was also measured at baseline (week 0), post-placebo (week 8) and post-intervention (week 16) using the Oral Nitrate Test (ONT) protocol, which is based on the physiological characteristics of the entero-salivary circulation of plasma nitrate and involves the consumption of a very low nitrate meal, followed by the collection of six saliva samples over a 2-day period. Isotopic composition is measured using GC/MS. The protocol measures the disappearance of an oral dose of Na15NO3 (labelled sodium nitrate) in saliva samples. The isotopic decay is defined by an exponential function for a single compartment. Data are expressed using a semi-logarithmic plot and the slope and intercept of the regression line are utilised to calculate the NO production rate. 2. Vascular/endothelial function measurements were measured at the same time points as stated above; except for blood pressure which was also measured at 2 intermediate study visits (weeks 4 and 12). The measurements consisted of carotid intima media thickness (cIMT), pulse wave velocity (PWV) and blood pressure. | — |
Countries
United Kingdom
Outcome results
None listed