Effects of Peas on Blood Glucose Control

Diabetes is one of the most common chronic diseases affecting Canadians (PHAC, 2011). Lifestyle modifications that include a diet high in fibre may lower the risk of developing type 2 diabetes (CDA, 2013). In this context, the presence of fibre in carbohydrate rich foods has been widely recognized for its effect on post-prandial glucose response (PPGR). Peas are high in fibre and protein and show great potential as a functional food. A health claim for PPGR would increase market demand for peas, and help those who want to limit the rise in blood sugar after a meal choose products to meet their goals, but there are several gaps in the literature that need to be filled before a submission to Health Canada can be successful: 1) test foods in appropriate serving sizes; 2) test both the glucose and insulin response; 3) test varieties of peas that that currently available on the market; 4) test whole/split peas (not fractions or isolates); 5) compare peas to appropriate starchy reference food (rice or potato). The proposed study design will address all of these gaps in the current literature and take into consideration Health Canada's guidance document for health claims related to the reduction in PPGR, which sets out the criteria by which the validity of such claims will be assessed.

Specific objectives

1. To determine the effect of 3 common market classes of peas on PPGR and insulin response in a cross-over, randomized, controlled clinical trial.
2. To assess the effect of 3 common market classes of peas on appetite-related sensations using visual analog scales.
3. To demonstrate whether the test and reference products were liked or disliked similarly by participants.
4. To assess any gastrointestinal side effects from eating the test products

A randomized, controlled, cross-over study designed to examine the PPGR to peas will be conducted at the I.H. Asper Clinical Research Institute in Winnipeg, Manitoba. The study will be divided into 2 groups of 24 healthy volunteers each. In Group 1, eligible participants who have provided consent will be asked to attend 6 clinic visits in a fasted state. Participants will be given white bread at their first and last visits, peas with rice at 3 visits and rice at 1 visit. At each visit participants will provide 7 blood samples via finger poke, 6 questionnaires about their appetite and a questionnaire about the acceptability of the test food. Each visit will last approximately 2.5h and be separated by 3-10 days. Group 2 will undergo the exact same study procedures as group 1, but rice will be replaced with potato.

Eligibility Criteria:
Inclusion criteria

1. Generally healthy male or female, between the age of 18-40 years;
2. Body mass index (BMI) 18.5-34.5 kg/m2;
3. HbA1c \<6.0%;
4. Willing to provide informed consent;
5. Willing/able to comply with the requirements of the study.

Exclusion criteria

1. Pregnant or lactating;
2. Medical history of diabetes mellitus, fasting plasma glucose ≥7.0 mmol/L or use of insulin or oral medication to control blood sugar;
3. Medical history of cardiovascular disease
4. Systolic blood pressure \>140 mmHg or diastolic blood pressure \>90 mmHg;
5. Fasting plasma total cholesterol \>7.8 mmol/L;
6. Fasting plasma HDL \<0.9 mmol/L;
7. Fasting plasma LDL \>5.0 mmol/L;
8. Fasting plasma triglycerides \>2.3 mmol/L;
9. A change in blood glucose concentration less than 1 mmol/L between baseline and 30 minutes after consumption of white bread at visit 1;
10. Maximum blood glucose concentration occurs after 60 minutes after consumption of white bread at visit 1;
11. Major surgery within the last 3 months;
12. Medical history of inflammatory disease (ie. Systemic lupus erythematosis, rheumatoid arthritis, psoriasis) or use of any corticosteroid medications within 3 months;
13. Medical history of liver disease or liver dysfunction (defined as plasma AST or ALT ≥1.5 times the upper limit of normal (ULN));
14. Medical history of kidney disease or kidney dysfunction (defined as blood urea nitrogen and creatinine ≥ 1.8 times the ULN));
15. Presence of a gastrointestinal disorder, daily use of any stomach acid-lowering medications or laxatives (including fibre supplements) within the past month or antibiotic use with the past 6 weeks;
16. Active treatment for any type of cancer within 1 year prior to study start;
17. Other medical, psychiatric, or behavioral factors that in the judgment of the principal Investigator may interfere with study participation or the ability to follow the intervention protocol;
18. Shift worker;
19. Tobacco use current or within the last 3 months;
20. Allergies to peas;
21. Aversion or unwillingness to eat study foods;
22. Consuming \>4 servings of pulses per week;
23. Use of any prescription or non-prescription drug, herbal or nutritional supplement known to affect glycemia;
24. Participation in another clinical trial, current or in the past 4 weeks;
25. Unstable body weight (defined as \>5% change in 3 months) or actively participating in a weight loss program.