effects of combining cocoa and soy in type 2 diabetes

Conditions: Type 2 Diabetes; Dietary Intervention

Summary: diabetes is an increasingly common condition affecting millions of people world wide. the cornerstone of treatment is lifestyle that includes looking at the way how people eat. it is known that food containing compounds called polyphenols can reduce the risk of heart disease risk in people with diabetes. two foods that are rich sources of polyphenols are cocoa (epicatechins) and soy (isoflavones). previous studies have shown the benefits of these foods in the diets of people with diabetes. it has also been shown that soy isoflavones and cocoa polyphenols can improve the mood in certain groups of patients. what is not known is whether there is any extra benefit of combining soy protein and isoflavones with cocoa. the aim of the study is to look at the modification of cardiovascular risk by soy and/or cocoa in patients with type 2 diabetes, alone or in combination.

1. general information about the study the target number of participants is 100. all participants are patients with type 2 diabetes on diet alone or metformin treatment. participants will be asked to eat two soy bars daily for 8 weeks. the length of the study is 10 weeks and involves 4 visits at the diabetes research centre in hull, uk. the bars will contain: * soy protein alone, or * soy protein with additional isoflavones, or * soy protein with cocoa, or * soy protein with isoflavones and cocoa, or * placebo bars without soy protein, isoflavones or cocoa. the study is randomised (a computer based allocation schema will be used to decide which bars the participant will need to consume). participants have the same 20% chance to be participant of any of the above groups. the study is placebo-controlled (there is one arm of placebo bars without soy protein, additional isoflavones or cocoa). the study is double-blind (neither the participants or the research team will know which bars they will take). 2. study-specific procedures visit 1 (week 0). non-fasting visit. interested participants discuss the study with a member of the study team who will explain each aspect of the study, following which informed consent will be then obtained. subsequently, blood pressure, weight, height and waist circumference will be measured, medical history and list of medication are recorded, and blood is taken to determine eligibility. a dietitian will explain about eating a normal diet and the foods we would like the participants to avoid during the study. vegetarian patients may include too much soy in the diet and for this reason they will not be able to take part in the study. all participants will be non smokers. visit 2 (week 2)and visit 4 (week 10). fasting visits. fasting blood is taken and the endopat is performed. weight, height and waist circumference measurement performed. the endopat test takes between 20-30 minutes. the first box of study bars is dispensed during visit 2. participants need to consume two bars daily. all remaining uneaten bars and empty wrappers will be collected during visit 4. visit 3 (week 6). non-fasting visit. height, weight, abdominal circumference, blood pressure are measured. second box of study bars is dispensed. participants are asked to complete a one week food diary and a three day hunger questionnaire before the fasting blood tests. the food diary includes mood rating scales to assess the effect of the consumption of the bars on mood. participants need to complete these prior to visit 2 and visit 4. participants have 24 hours blood pressure measurement prior to visit 2 and visit 4. 24 hours urine collection also takes place prior to visit 2 and visit 4. 3. optional test incorporated into the study: body volume index measurement based on participants preference, body volume index measurement is offered as a complementary tool to assess body shape and weight.

Eligibility criteria:
inclusion criteria: * patients with type 2 diabetes controlled by diet or metformin only * stable medication history for 3 months prior to screening visit * age 45-80 exclusion criteria: * patients with concurrent illness or any medication (especially antibiotics)3 months prior to enrollment that would effect the study results based on investigator's judgement * patients not wishing to allow disclosure to their gps * pre-menopausal women or on hormone replacement therapy * hba1c \>9% at screening * patients with known food allergies * smokers * vegans and vegetarians

Keywords: type 2 diabetes cardiovascular risk endothelial function insulin resistance soy isoflavones cocoa diet