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

Overview

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.

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.