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- Most people commonly eat plant foods rich in starch, notably cereal products (e.g. bread, rice), and also some that are rich in fat (e.g. tree nuts). However, little is known about how such foods release starch and fat in the human gut and how, in turn, this may influence digestion and ultimately the absorption of nutrients into the body. Improving our understanding of these processes is important for basic scientists studying the behaviour of foods in the gut and their effects on metabolism. It is also important for health professionals and policy makers that are worried about excessive food consumption and the growing problem of obesity and associated problems of heart disease and diabetes. Moreover, the rate and extent of starch and fat digestion and absorption into the blood stream are important factors in altering the risk of heart disease. The release of fat and starch from plant foods and the digestion and absorption of these nutrients by the body are highly complex processes. Our progress in understanding these processes is impeded by the hugely complex structure and properties of plant foods and individual nutrients. Our project proposal brings together a unique combination of world experts from different institutions and disciplines. These experts have formed a large team in order to improve our knowledge of how edible plants behave in the gut and how the gut reacts to the starch and fat available for digestion. For example, it is important to know about the rate at which nutrients are released from plant foods as they move along the gut, since this will affect the time course of digestion and absorption. This in turn will influence the way the nutrients are metabolised within the body. We currently study almond nuts and cereals, e.g. wheat, to see how fat and starch are released from plant tissues. Starch, fat and other nutrients are found inside numerous cells that make up the plant tissue, e.g. an almond seed contains about 50 million cells. Such cells are very small in size, often with a diameter of less than about one tenth of a mm. One significant factor that seems to affect nutrient release from plant cells is the presence of cell walls, more commonly referred to in nutrition as 'dietary fibre'. How starch and fat are released from these cells is poorly understood. Initial studies will involve examining the role of cell walls as physical barriers in controlling the release and digestion of nutrients, using various methods to examine plant tissue at a cellular scale. One novel method will be the use of a recently established 'Dynamic Gastric Model', a computer-controlled simulation of digestion in the human stomach. We will also feed human volunteers with the same plant foods rich in fat and starch, to determine the effects of processing and mastication on nutrient release and digestion and the rate at which digested nutrients are transported into the blood stream. Finally, we will also produce a mathematical description of how fat and starch are released from edible plant tissues during digestion. It is envisaged that in the future, the use of mathematics will allow research scientists to predict the behaviour of similar foods in the gut without having to do so many laboratory experiments. This work will help the food industry to produce new food products or ingredients that have a controlled release of starch and fat in the gut, which could, for example, help to reduce the risk of heart disease. Indeed, Premier Foods, a large food manufacturer, has agreed to collaborate with us and provide scientific and technological expertise. Premier Foods has also agreed to provide cereals (e.g. wheat) and food products made with these cereals, all of which have been specially prepared to control starch release. These raw materials and food products will be used in our project to study how they behave in the gut and assess their potential benefits in reducing the risk of heart disease.