A Study to Examine the Glycemic Response of Corn and Soy Tortillas in Healthy Individuals

Not Applicable

Completed

• Conditions: Healthy
• Interventions: Other: Oral Glucose Solution 296 mls; Other: Corn Tortilla; Other: Low Soy Flour Corn Tortilla; Other: Moderate Soy Flour Corn Tortilla; Other: High Soy Flour Corn Tortilla

• Registration Number: NCT01828671
• Lead Sponsor: University of Manitoba

Brief Summary

Tortillas are a staple food in several cultures and are widely used to make tacos, burritos, and enchiladas. These foods are gaining a significant segment of the North American fast food and restaurant industry. From a health point of view, the addition of soy flour into corn tortillas will improve the nutritional profile of the tortillas and the presence of soy protein, dietary fibre and bioactive components has the potential to yield other health benefits. It is hypothesized that the addition of soy flour to corn tortillas will lower the glycemic index which could benefit those individuals with type 2 diabetes.

The purpose of this research is to investigate whether different levels of soy flour in corn tortillas influences the glycemic response.

Detailed Description

Soybeans are an important crop in Canada, with approximately 10% of soybean production in Manitoba. Soybeans are grown primarily for their oil. The press cake that remains following oil extraction is a good source of protein and contains bioactive ingredients such as the isoflavones. The press cake can be ground into a flour (soy flour) and used in food products. For example, a finely ground flour can be used in infant formulas as well as for meat and dairy substitutes. This research is examining other applications of soy flour in food products such as corn tortillas. Tortillas are a staple food in several cultures and are widely used to make tacos, burritos, and enchiladas. These foods are gaining a significant segment of the North American fast food and restaurant industry. From a health point of view, the addition of soy flour into corn tortillas will improve the nutritional profile of the tortillas and the presence of soy protein, dietary fibre and bioactive components has the potential to yield other health benefits. It is hypothesized that the addition of soy flour to corn tortillas will lower the glycemic index. The glycemic index describes the potential of a food to increase blood glucose post-prandially in relation to the same amount of available carbohydrate in a glucose solution. Consumption of low glycemic index foods helps to achieve better glycemic control in individuals with type 2 diabetes. Recent meta-analyses are reporting that consumption of high glycemic index foods is associated with higher risk of coronary heart disease and breast cancer in women.

The purpose of this research is to investigate whether different levels of soy flour in corn tortillas influences the glycemic response. This information will form the basis of developing food products for glycemic management in type 2 diabetes and for reducing risk of other chronic diseases.

This single site, double-blind, randomized, controlled study designed to examine the glycemic response to corn and soy tortillas in healthy individuals will recruit 10 eligible volunteers into the study who will visit the research clinic on 6 separate visits for the glycemic testing. At each visit, one of the following products will be consumed: i) 296 mls (\~1 cup) of oral glucose solution; ii) 296 mls (\~1 cup) of oral glucose solution for a duplicate assessment as per standard glycemic index testing protocols; iii) corn tortillas; iv) corn tortillas with a low amount of soy flour; v) corn tortillas with a moderate amount of soy flour; or vi) corn tortillas made with a higher amount of soy flour.

Study Timeline

• Study First Submitted: 2013-04-07
• Study First Submitted QC: 2013-04-10
• Study First Posted: 2013-04-11
• Study Start: 2013-12
• Primary Completion: 2014-04
• Status Verified: 2014-05
• Study Completion: 2014-05
• Last Update Submitted: 2014-05-13
• Last Update Posted: 2014-05-15

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 10

Inclusion Criteria

• Male or female, greater or equal to 18 and less than or equal to 40 years of age;
• Normal blood lipid profile (total cholesterol, LDL-cholesterol, HDL- cholesterol, triglycerides) and glycated hemoglobin <6%;
• Body mass index (BMI) of 20 to 30;
• Stable regime for the past 3 months if taking vitamin and mineral/dietary/herbal supplements;
• Agree not to eat soybeans (edamame) or soy-based foods, or consume soy or isoflavone supplements while participating in this study;
• Willing to comply with the protocol requirements;
• Willing to provide informed consent.

Exclusion Criteria

• Allergies to corn or soy flour or to corn or soy products;
• Presence of a clinically diagnosed disease affecting the circulatory, respiratory, immune, skeletal, urinary, muscular, endocrine, digestive, nervous or reproductive system that requires medical treatment;
• Taking any prescribed medication (with the exception of birth control) within the last 3 months, or taking supplements which affect glycemic control within the last 3 months;
• Cigarette/cigar smoking, current or within the last 6 months;
• Current (within the last 30 days) bacterial, viral or fungal infection, or taking over-the-counter medication within the past 72 h;
• Pregnancy or lactation.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: FACTORIAL

Arm && Interventions

Group	Intervention	Description
Oral Glucose Solution 296 ml	High Soy Flour Corn Tortilla	Study Participants will consume oral glucose solution 296 mls. Blood will be sampled via capillary at time-point 0 (before the product is consumed), and 15, 30, 45, 60, 90 and 120 minutes after consumption to determine blood glucose concentrations using a glucometer. Per standard glycemic index testing protocols, this will be repeated at another visit.
High Soy Flour Corn Tortilla	Oral Glucose Solution 296 mls	Study Participants will consume 2 to 3.5 tortillas (12-15 cm in diameter each) with a high amount soy flour that has 25 grams of available carbohydrate. Blood will be sampled via capillary at time-point 0 (before the product is consumed), and 15, 30, 45, 60, 90 and 120 minutes after consumption to determine blood glucose concentrations using a glucometer.
Oral Glucose Solution 296 ml	Low Soy Flour Corn Tortilla	Study Participants will consume oral glucose solution 296 mls. Blood will be sampled via capillary at time-point 0 (before the product is consumed), and 15, 30, 45, 60, 90 and 120 minutes after consumption to determine blood glucose concentrations using a glucometer. Per standard glycemic index testing protocols, this will be repeated at another visit.
Low Soy Flour Corn Tortilla	Oral Glucose Solution 296 mls	Study Participants will consume 2 to 3.5 tortillas (12-15 cm in diameter each) with a low amount of soy flour that is 25 grams of available carbohydrate. Blood will be sampled via capillary at time-point 0 (before the product is consumed), and 15, 30, 45, 60, 90 and 120 minutes after consumption to determine blood glucose concentrations using a glucometer.
Oral Glucose Solution 296 ml	Corn Tortilla	Study Participants will consume oral glucose solution 296 mls. Blood will be sampled via capillary at time-point 0 (before the product is consumed), and 15, 30, 45, 60, 90 and 120 minutes after consumption to determine blood glucose concentrations using a glucometer. Per standard glycemic index testing protocols, this will be repeated at another visit.
Oral Glucose Solution 296 ml	Moderate Soy Flour Corn Tortilla	Study Participants will consume oral glucose solution 296 mls. Blood will be sampled via capillary at time-point 0 (before the product is consumed), and 15, 30, 45, 60, 90 and 120 minutes after consumption to determine blood glucose concentrations using a glucometer. Per standard glycemic index testing protocols, this will be repeated at another visit.
Corn Tortilla	Oral Glucose Solution 296 mls	Study Participants will consume 2 to 3.5 corn tortillas (12-15 cm in diameter each) with a total serving of 25 grams of available carbohydrate. Blood will be sampled via capillary at time-point 0 (before the product is consumed), and 15, 30, 45, 60, 90 and 120 minutes after consumption to determine blood glucose concentrations using a glucometer.
Moderate Soy Flour Corn Tortilla	Oral Glucose Solution 296 mls	Study Participants will consume 2 to 3.5 tortillas (12-15 cm in diameter each) with moderate amount of soy flour that has 25 grams of available carbohydrate. Blood will be sampled via capillary at time-point 0 (before the product is consumed), and 15, 30, 45, 60, 90 and 120 minutes after consumption to determine blood glucose concentrations using a glucometer.

Primary Outcome Measures

Name	Time	Method
Blood glucose as measured via capillary sampling using glucometer	0, 15, 30, 45, 60, 90 and 120 minutes	Blood will be sampled via capillary finger prick at time-point 0, (before the product is consumed), and 15, 30, 45, 60, 90 and 120 minutes after the first bite of the tortillas or first sip of the glucose solution to determine blood glucose concentrations using a glucometer.

Trial Locations

Locations (1)

St. Boniface General Hospital - Asper Clinical Research Institute; 🇨🇦 Winnipeg, Manitoba, Canada