Assessment of the glycemic index of groats available on the Polish food market

Background: Glycemic index (GI) and glycemic load (GL) are often used to assess diet quality in relation to the risk of diabetes, cardiovascular diseases and cancer development. Taking into account differences in nutritional value of food products in different countries it is often suggested to used national databases to assess dietary intake in different populations.

Objective: To assess the glycemic index and glycemic load of the selected groats available on the Polish food market.

Material and methods: GI of the following groats available on the Polish food market was assessed: couscous, buckwheat (roasted) groats, millet groats, spelt groats, barley (hulled) groats and bulgur groats. The GI was assessed as the incremental area under the blood glucose response curve of a 50g carbohydrate portion of a test food expressed as a percent of the response to the same amount of carbohydrate from a standard food taken by the same subject. GL was calculated for the 100 g of the cooked product.

Results: The lowest GI was found for buckwheat (34.7±8.2%) and barley (31.3±13.4%) groats. The GL for these groats was 8.1±1.9 and 8.0±3.4, respectively. The GI for millet, spelt and bulgur groats amounted to 56.2±20.6%, 69.8±35.0%, 64.5±36.8%, respectively, while for couscous amounted to 99.0± 36.0%. The highest GL was observed for couscous (24.7±9.0).

Conclusions: The groats tested in this study can be classified as follows: barley and buckwheat as a low GI food, millet and bulgur as a medium GI food, spelt and couscous as a high GI food. Buckwheat and barley groats should be chosen the most often among these products, while the intake of couscous should be limited especially by people with diabetes.