The effect of dietary fibre and protein from lupin on blood glucose in type 2 diabetes

INTERVENTION: A study of the acute effects of dietary fibre and protein from legumes (when added to drinks) on blood glucose and insulin levels will be assessed. Three treatments, administered in random order at least 1 week apart, will be compared – 1) lupin flour high in protein and fibre [50 g of flour containing 22 g protein and 12.5 g fibre], plus 50 g glucose; 2) Soy protein [22 g] and fibre [12.5 g] provided as a mixture of isolated soy protein and concentrated soy fibre, plus 50 g glucose; 3) 50 g glucose (carbohydrate‐matched control). Each treatment will be consumed as a 600 ml beverage, consumed over a 15 minute time period. Each treatment corresponds to a single clinic visit lasting 5 hours. Participants attend the clinic after a 12 hour overnight fast. A venous cannula will be inserted in the antecubital fossa vein and after a 15 minute rest baseline blood samples will be drawn. The treatment beverage is consumed, then blood samples are taken every 15 minutes for 1 hour, then every 30 minutes to 2 hours and then hourly to 4 hours. CONDITION: type 2 diabetes PRIMARY OUTCOME: Plasma glucose concnetrations assessed using routine biochemical techniques performed in an accredited pathology laboratory Plasma insulin concnetrations assessed using routine biochemical techniques performed in an accredited pathology laboratory SECONDARY OUTCOME: Incretin hormones including glucagon‐like peptide‐1 (GLP‐1) assessed using a commercially available assay INCLUSION CRITERIA: Diagnosis of type 2 diabetes within the previous 10 years (confirmed by a general practitioner, or evident at screening with fasting glucose > 7 mmol/L); age 35‐65 years; body mass index < 40kg/m2; glycated haemoglobin < 9%.