Lowering Post-Prandial Glycaemia
Glycaemic Index is a ranking of foods from 0-100 that tells us whether a food will raise blood sugar levels just a little, moderately or dramatically.
05/08/05 There is growing interest in the quantity and quality of carbohydrate in the diet since the evidence from 20 years of clinical research confirms the potential for disease-risk reduction by lowering post-prandial glucose levels.
We also know that the chemical nature of carbohydrates is not a reliable indicator of physiological effect. However, glycaemic index (GI) is an established index that classifies foods based on their potential to increase blood glucose.
The concept was first developed in the early 1980s at the University of Toronto to help determine which foods were best for people with diabetes. It was discovered that different carbohydrate-containing foods produce different blood sugar responses. Interesting facts emerged; for instance, ice cream has much less effect on blood sugar than ordinary white bread, despite its high sugar content. The GI factor was determined to account for such differences and is related to the relative rate of breakdown of foods during digestion.
Glycaemic Index tables exist that rank over 1000 foods by GI, including pure carbohydrates and commercial products.
Glycaemic Index is a ranking of foods from 0-100 that tells us whether a food will raise blood sugar levels just a little, moderately or dramatically.
Low GI foods - < 55
Intermediate GI foods - 55-70
High GI foods - >70
Low GI diets have been shown to:
Control established diabetes
Help people lose weight
Possibly help lower blood lipids
Improve the body’s sensitivity to insulin
Possibly help reduce the risk of heart disease
Be less likely to develop diabetes in middle age
Improve sports performance
Changes that are required to our diets should be based on using low GI foods, such as breakfast cereals based on wheat bran and oats, whole grain breads especially barley and rye, fruits such as pears, plums and apples and using pasta instead of potatoes. Many will recognise this as good, generally well-accepted nutritional and dietary advice. But in processed foods, where sugars and readily available carbohydrates such as highly refined flours and starches are commonly used in high quantities, it is not so simple to find low GI alternatives.
Most polyols, including lactitol and xylitol have a low GI. The speciality carbohydrate Litesse® (polydextrose) and fructose also have low GI values. These ingredients can replace sucrose and glucose, high GI polysaccharides such as starch and maltodextrin, as well as fat in a wide range of formulations, from beverages through to confectionery. In addition, it has been found that a preload of Litesse® can reduce the GI of a subsequent meal and reduce the GI of glucose itself when they are eaten together.
Reducing the glycaemic load of the diet is a valid objective and the growing evidence of clinical data confirms the potential for disease-risk reduction. Food processors have an opportunity to develop innovative new products. These will help to improve the nutritional profile of the diet. The full potential of the concept is still evolving, and communicating the message to consumers will be a creative challenge.
