The search has been on for some time to identify dietary strategies to tackle diabetes, which is estimated to affect around 4.8m people in the UK, including about a million undiagnosed individuals, and carries considerable cost to the NHS.
Type 2 diabetes accounts for about 90% of diabetes cases. It is the result of a progressive decline in the capacity of specialised cells in the pancreas to secrete insulin, the hormone that controls blood glucose levels. This decline can be accelerated by a poor diet and unhealthy lifestyle, and for some time a beneficial role for resistant starch in the diet has been recognised.
Resistant starch is a carbohydrate that resists digestion in the upper parts of the digestive tract, with some reaching the large bowel (colon) where it is fermented by the bacteria that reside there. Details can be found in a paper by Lockyer and Nugent. This process generates products known as short chain fatty acids which are thought to improve insulin secretion by acting on the specialised cells in the pancreas known as beta cells. Although a variety of fruits and vegetables contain resistant starch, UK diets generally contain low amounts.
The research is a collaboration between Imperial College London, the Quadram Institute and the John Innes Centre. It set out to study which features of starch structure are important in determining resistance to digestion, whether resistant starches from different food sources differ in their capacity to improve beta cell function and whether cooking method is important. The project aspired to identify strategies to reduce type 2 diabetes risk through development of new forms of common foods containing resistant starches.