Glycaemic Index Testing
We are the only centre in Europe and one of eight in the World accredited by the Glycemic Index Foundation to test foods for Glycemic Index
Why choose Brookes?
OxBCNH is internationally renowned for its work on glycaemic index (GI) and we have published extensively in this area. The OxBCNH is the only GI testing centre in Europe accredited by the Glycemic Index Foundation. Our procedure for GI testing is carried out in accordance with ISO 26642:2010 standards (ISO 26642:2010 Food Products – Determination of Glycaemic Index).
What is GI?
The glycaemic index (GI) is a method of ranking foods on a scale of 1 to 100 according to the extent to which a food raises blood sugar levels after ingestion. The principle is that the slower the rate of carbohydrate absorption, the lower the rise of blood glucose level and the lower the GI value. A GI value ≥70 is considered high, a GI value 56-69 (inclusive) is medium and a GI value ≤55 is low (where the glucose standard = 100).
How is GI measured?
Our GI tests involve a minimum of 10 healthy human participants, who are required to fast at least 12 hours before their test session. Prior to GI testing of a food, a control of three glucose references are measured on three different occasions.
On the day of testing:
- Two fasted capillary blood samples are taken by trained personnel
- The test food / glucose drink is consumed within 15 minutes
- Capillary blood samples are taken every 15 minutes for the first hour and then every 30 minutes for the next two hours
From the result obtained from stage two, the area under the curve (AUC) is calculated. This reflects the total rise in blood glucose levels after eating the test food or drink. The final GI value of a food is the average for all participants.
The GI of the food is calculated: