By Jane Dummer
It was 2004 and the no-carb craze still had momentum when I attended a
conference on Glycemic Index (GI) discussing topics such as the method
of determining the GI of foods and how the Canadian Diabetes
Association (CDA) educates its patients about GI.
|Flours made from pulses can help reduce the GI rating of baked goods|
The Glycemic Index, originally developed in Canada, is becoming an
important piece of nutritional information. Here’s what you need to
know about it.
It was 2004 and the no-carb craze still had momentum when I attended a conference on Glycemic Index (GI) discussing topics such as the method of determining the GI of foods and how the Canadian Diabetes Association (CDA) educates its patients about GI. The conference was in Toronto, where 23 years earlier Dr. David Jenkins and his colleagues at the University of Toronto developed a standardized system of ranking foods based on their effect on blood glucose levels, known as the GI.
“The GI is ranked from 0 to 100 and the unit of measure is percentage,” Jenkins says. “To make a fair comparison, all foods are compared to a reference food such as pure glucose (the original standard) or white bread (the more commonly used reference), which have a GI rating of 100. The number indicates whether a food raises your blood glucose rapidly (GI rating of 70 or more), moderately (56-60) or slowly (55 or less). Generally, foods that are digested quickly and cause your blood sugar to rise rapidly have high GI values.”
This GI food ranking approach, originated in Canada, is popular in Australia and is gaining ground in Europe and the United States. Studies support the notion that low-GI foods, as part of a healthy meal plan, contribute to sustained energy, better brain/memory performance and less of an inflammatory response. Other evidence shows that for people with Type 2 diabetes and heart disease, adhering to low-GI diets decreases the effect on blood sugar, increases good cholesterol (HDL) and lowers triglycerides (TG).
“The GI ranking of foods is an important concept for our consumers,” says Sharon Zeiler of the CDA. “It is vital to equip people who have diabetes with a GI ranking model. The CDA has created tools for health professionals and a handout for the consumer in a very simple format identifying the GI rating for different carbohydrate-containing foods. Studies out of Australia suggest patients educated on how to carbohydrate count plus choose foods based on GI rating have better control over their blood sugars than patients educated only with carbohydrate counting.”
What about the average Canadian consumer? What is their understanding of the GI?
“The Tracking Nutrition Trends (TNT) survey was first established in 1989 to examine adult Canadians’ perceptions of fat and fibre,” says Canadian Council for Food and Nutrition president and CEO Francy Pillo-Blocka. “The TNT survey continues to track attitudes about fat and fibre while incorporating emerging food, nutrition and health issues including GI.”
Findings from TNT VII (released in August 2008) suggest that knowledge of the GI continues to be moderate among Canadians, with half of the respondents understanding this concept. Also, in making food-based decisions, 39 per cent surveyed considered foods that have a low GI as somewhat influential or very influential. The latter fact is most likely to increase as more consumers become aware of GI.
With obesity and Type 2 diabetes on the rise in North America, consumers are looking for healthful foods with accurate nutrition information.
“Companies from North America are having their food products tested at our facility to help their consumers make informed choices,” says Katherine Corbett of Glycemic Index Laboratories in Toronto.
Fortunately, experts agree there is a standardized method to determine the GI rating of food. It’s based on a human biological response that is able to distinguish between high- and low-GI foods. The original Australian Standard, now expanded, is in the final approval stage at ISO – the International Organization for Standardization. In the near future, under ISO’s robust parameters, the document will be published. This will help regulators move forward with GI labelling guidelines.
So what does all this mean for the baking industry? Several factors determine a food’s GI. Processing techniques of carbohydrates will affect GI value, as well as other nutrients and ingredients in the product. For example, a higher fat content in the product will change how your body digests food, ultimately lowering the GI ranking; however, this does not make for an overall healthier product.
The type and quality of carbohydrate will have an effect on the GI ranking. In general, the courser the flour grinds, the longer the digestion time – and the lower the GI ranking. Research has shown that the lactic acid in sourdough delays gastric emptying, again leading to a lower GI ranking.
Bakery products possess a wide range of GI rankings. With that in mind, the industry has an opportunity to lower the GI rating of products by being innovative and exploring the use of vegetable proteins, increasing viscous fibre (with beta glucans), and adding pulse (beans, peas, lentils and chickpeas) flours.
As consumer trends move toward a more balanced approach to nutrition and diet, we are still faced with soaring obesity rates. Choosing products with low GI ratings is an important factor in an overall food cocktail to fight this growing problem. As consumers are reminded to check portion sizes and increase physical activity, the industry needs to offer healthful options with accurate nutrition information, statements and claims, so informed choices can be made.