The Effect of Dietary Nitrate Supplementation on Ability of Individuals With Type 2 Diabetes to Perform Exercise

The investigators are conducting a research study to see if increasing the amount of nitrate (a substance found in large quantities in certain vegetables) in the diet can increase the ability of individuals with Type 2 diabetes (T2D) to perform exercise. Some people with T2D find exercise more uncomfortable than individuals who do not have T2D. This may be explained by the experimental studies showing that T2D can result in reductions in the supply of oxygen to the muscles. Studies have also shown that for a given level of activity, individuals with T2D will be much closer to their maximum exercise capacity than healthy individuals. Dietary nitrate may have two important beneficial effects in individuals with T2D: 1) The effects of dietary nitrate on the responses to exercise may have a significant impact on the ability of individuals with Type 2 diabetes to perform daily tasks and exercise more comfortably and 2) experimental studies suggest that increased nitrate consumption has been shown to reduce the amount of oxygen required for a given level of exercise.

The investigators will recruit 60 individuals with T2D. These people will take part in a randomised crossover design study where they will be asked to drink normal beetroot juice (rich in nitrate) and nitrate depleted beetroot juice, prior to performing two different walking exercise tasks (a six minute walk and repeated, low intensity treadmill walking). This study aims to determine if dietary nitrate supplementation reduces the amount of oxygen required for a given level of exercise in individuals with T2D. To test brain function individuals will be asked to perform a standard computerised decision making task following consumption of the nitrate rich and nitrate depleted juices.