Acute Studies on the Glycemic Index After Intake of Different Sorts of Barley in Subjects With Type 2 Diabetes

Approx. 60 mio. people worldwide live with diabetes and the prevalence is increasing. The increase is primarily due to obesity, unhealthy diet and lack of physical activity. Therefore, it is important to find dietary products that counteracts this development.

Intake of food with a low glycemic index (GI) reduces the risk of developing type 2 diabetes (T2D) and helps in the regulation of a preexisting diabetes.

Barley has shown some beneficial effects on GI compared with wheat, however, barley is not commonly used in bread making in Denmark.

The most common type of barley in Denmark is with rind and demands processing before use. Processing may remove important nutrients from the barley. Some of the original antiquity barley has a loose rind (nude barley), that falls of during harvesting, and thereby reduces the need for processing. However, it is not known how this ancient type of barley affects GI.

The composition of the starch in barley is of importance when the grain is degraded after consumption. The starch consists of both amylose (which is slowly degraded) and amylopectin (which is quickly degraded). By genetic modification, it was possible for collaborative researchers at the Universities of Aarhus and Copenhagen to increase the amount of amylose in regular barley. Slowly degraded starch is expected to decrease GI.

In a series of acute studies the investigators want to study the effects on the glucose metabolism to intake of bread made with different compositions of wheat, nude barley and gene-modified high-amylose barley in subjects with T2D.

It is expected that both nude barley and gene-modified high-amylose barley lowers the postprandial glycemic response more than wheat and hereby positively affect the glycemic regulation for subjects with type 2 diabetes.

Inclusion criteria

• Type 2 diabetes (T2D) defined by standard Danish guidelines.
• HbA1c between 48-78 mmol/l.
• Treatment with drugs for hypertension and high cholesterol is allowed if the treatment dose is stable and does not demand changes during the study period.
• Participants are encouraged to maintain their present psychical activity level and their smoking and alcohol habits.

Exclusion criteria

• Type 1 diabetes
• Insulin demanding T2D
• Use of weekly administrated GLP-1 antagonist (e.g. ozempic, trulicity or byetta)
• Use of acarbose
• Significant cardiovascular, kidney, liver or endocrine comorbidity
• Significant psychiatric history
• Treatment with steroids
• Alcohol or drug abuse
• Pregnancy or breastfeeding
• Legally incompetent