Effects of Acute Intake of Caffeinated Beverages in Type 1 Diabetes

The aim of this pilot study is to determine the impact of caffeine-enhanced energy drinks on blood glucose excursion on heart rate, blood pressure, cardiac output and cognitive performance in patients with type 1 diabetes.

Knowledge acquired may inform a wider study of the impact of these drinks.

This is a randomised, cross over blinded study in which all participants will participate in the 3 arms of the study.

The study will consist of 3 phases, each lasting 3 days. A different study drink will be administered during each phase. There will be an initial screening visit and a pre- study visit before each study phase. Each participant will make 10 visits to the research centre.

There will be a week wash out period between each study phase. Prior to each study phase, there will be a 3 day caffeine and alcohol abstinence run-in period.

Study drinks will be matched for taste and volume (as far as possible) and will be administered by the use of opaque cups, lids and straws to enable double-blind randomisation for both researcher and participants. Administration of the study drink to participants will be based on Latin squares to provide a balanced treatment order.

During the 3 days study period; participants will be required to abstain from all other caffeine containing beverages or confectioneries.

The secondary aim is to determine if tolerance to cardiovascular effects of caffeine-enhanced energy drinks is developed following acute short term ingestion.