GI research gains ground but uncertain future in Europe
reducing risk of type 2 diabetes may benefit high-fibre foods and
those using healthy ingredients.
But a proposed European health claims regulation will play a role in the success of this dietary approach. In its current form the proposal makes no reference to the use of glycaemic index (GI) claims, despite its clear relevance to healthy eating.
The use of a 'glycaemic index', which rates a carbohydrate food according to how fast it is broken down into sugar by the body, is gaining increasing attention from nutritionists, food manufacturers and retailers. Already well established in Australia, the GI is seen in Europe as a more sensible approach to the 'low-carb' craze currently sweeping America - rather than removing 'carbs' altogether from the diet, it looks at carbohydrate type.
But 'low GI' foods are not only being promoted for weight loss. It appears that paying close attention to the GI value of one's diet could also reduce the risk of the serious obesity-related diseases.
New studies in the August issue of the American Journal of Clinical Nutrition seem to support this theory. Researchers from the Harvard School of Public Health and Brigham and Women's Hospital report that a diet high in rapidly absorbed carbohydrates and low in cereal fibre is associated with an increased risk of type 2 diabetes.
Analysing data from more than 91000 women over an eight-year period, they found glycaemic index was significantly associated with an increased risk of diabetes. Conversely, cereal fibre intake was associated with a decreased risk of the disease in the study (vol 80, no 2, 348-356).
Another study (pp337-347) by scientists at the Royal Veterinary and Agricultural University in Frederiksberg, Denmark and Lund University in Sweden found that although a low-fat, low glycaemic index diet had no greater benefit to weight loss than a low-fat, high glycaemic diet, it did benefit risk factors for ischemic heart disease.
In the ten-week parallel, randomised, intervention trial on 45 adults, the low glycaemic index diet brought a 10 per cent decrease in LDL cholesterol and a tendency to a larger decrease in total cholesterol compared with the high glycaemic index diet.
In an editorial in the same journal, Jennie C Brand-Miller from the University of Sydney, Australia notes that "prevention of type 2 diabetes is one of the biggest challenges facing public health in the 21st century".
She adds that studies such as the Diabetes Prevention Program have shown that intensive diet and exercise programmes are "not only highly effective in delaying or preventing the disease but are more cost-effective than even the cheapest drug".
There are however some problems with the glycemic index. Many breads and cereal products have unknown GI values, making this a significant source of error. And there is some difference of opinion on whether glycaemic load, which relates to portion sizes, is more important than a food's glycemic index.
There is also some conflicting evidence on the benefits of the GI diet. This may not help food makers hoping to draw a consumer's attention to a low-GI food with labelling. The European Commission's draft proposal on health claims is strict on all claims relating to weight loss.
However, such issues have not stopped the UK's number one supermarket Tesco from introducing new food labels that rank a product according to its position on the glycemic index.
Ingredient makers are also preparing for increased interest in carbohydrate type.
"The next phase in the low carb hype is the 'slow carb' trend," according to Liesbeth Neven, product manager of health ingredients at Acatris. "Healthcare professionals and consumers know that we need some carbohydrates in our diets. The key is to understand which types of carbs are beneficial."
Ingredients, such as the firm's FenuLife fenugreek extract, are now being pitched at the emerging trend for 'low GI' foods. Other fibre suppliers carefully watching this trend include Japan's Taiyo Kagaku which makes SunFiber, produced from guar beans, National Starch with its Hi-maize resistant starch, and the sugar replacer Isomalt.
Industry may however need to begin lobbying their MEPs if they want to be able to successfully market low-GI foods in the future. European legislation on health claims is set to pick up pace under the new Dutch presidency, which appears to be aiming for the regulation to get its first reading in the European parliament by December.