A Comparison Chocolate With and Without High Cocoa Solids in Patients With Type 2 Diabetes in a Randomised Clinical Trial
A Comparison Chocolate With and Without High Cocoa Solids in Patients With Type 2 Diabetes in a Randomised Clinical Trial
Type 2 diabetes is being acknowledged as a potential public health time bomb, whose incidence
 is predicted to double over the next 10 years in the UK, associated with the rise in obesity
 and increasing sedentary lifestyles. Increased insulin resistance has been shown to be an
 important feature of type 2 diabetes (especially in those presenting with obesity and in
 particular visceral or abdominal obesity). Insulin resistance is implicated as a risk factor
 of cardiovascular disease and may lead to pancreatic dysfunction through increased β-cell
 stress in the pancreas. A combination of insulin resistance and pancreatic beta cell failure
 then leads to type 2 diabetes. The main cause of morbidity and mortality in type 2 diabetes
 is cardiovascular disease as the condition is associated with impaired vascular functioning
 and increased levels of oxidation markers.

 Epidemiological studies suggest dietary flavonoids decrease the risk of death from coronary
 heart disease, cancer, and stroke. Flavonoid-rich foods include fruits and vegetables as well
 as tea, red wine, and chocolate. In a cohort of elderly men, cocoa intake was inversely
 associated with blood pressure and 15-year cardiovascular and all-cause mortality. It has
 been reported that in healthy humans, consumption of flavanol-rich dark chocolate decreased
 daytime and night time blood pressure, reduced insulin resistance, and improved nitric oxide
 dependent vaso-relaxation. Another trial found that cocoa powder increased postprandial
 insulinaemia in lean young adults. These research papers have led to the hypothesis that
 chocolate containing high cocoa liquor may help to reduce the risk of developing type 2
 diabetes.

 This study is design as a double-blind, controlled, single center, randomized, parallel
 design clinical trial. The primary outcome measure is to compare parameters of insulin
 resistance and glycaemic control in volunteers with type 2 diabetes after consumption of 3
 different chocolates (one dark and two milk chocolates) with a secondary outcome of
 endothelial function, cholesterol profile and oxidative stress. Subjects will undergo medical
 screening, anthropometry, physical activity and dietary assessments before randomization.
Inclusion criteria:

 -  The diagnosis of type 2 diabetes will be based on the WHO guidelines. These are 2
 fasting plasma glucose readings of greater than 7.0mmoll-1 or 2 random plasma glucose
 readings >11mmoll-1 in the absence of symptoms or concurrent illness or medication
 which might lead to hyperglycaemia (e.g. thiazide diuretics). Or one reading meeting
 the diagnostic level with the presence of symptoms of polyuria, polydipsia, nocturia,
 fatigue or blurring of vision. The final diagnostic method of diagnosis type 2
 diabetes is a positive oral glucose tolerance test (OGTT) using a 75g glucose load. If
 doubt exists on the diagnosis of diabetes an OGTT will be performed.

 -  Diabetes managed by diet alone or diet and metformin. If metformin is used the dose
 should have been stable for a minimum of 3 months prior to the start of the study.

 -  Hba1c up to and including 9.9%

 -  Age 45-75

 -  If female, should be post-menopausal

 -  BMI 25-39kgm-2

 -  Patients will have attended a structured group patient education programme (and be on
 stable medication for hypertension, lipids and gout (if appropriate) for 3 months
 prior to entry into the study. Subjects will be encouraged to incorporate the
 chocolate into their diet as advised during the education programme

 -  Having obtained his/her or his/her legal representative's informed consent.

 Exclusion Criteria:

 -  Patients with concurrent illness or any changes in medication in the last 3 months.

 -  Patients whose diabetes is managed with TZDs, DPP-IV inhibitors, GLP-1 analogues,
 insulin or sulphonylureas or prandial regulators

 -  Patients not wishing to allow disclosure to their GPs.

 -  Pregnancy

 -  Hba1c at recruiting stage of >10.0%

 -  Patient who cannot be expected to comply with treatment

 -  Currently participating or having participated in another clinical trial during the
 last 3 months prior to the beginning of this study

 -  Patients who consuming more than 20g/d of chocolate or having a very high polyphenol
 content of their diet, who are not willing to change their diet

 -  Patients taking high dose antioxidant supplements including single and multivitamin
 preparations including A,C,E.

 -  Women on HRT treatment