Once we know which dietary fibres give people a feeling of fullness, it will be possible to produce food which provides a high degree of satiety and which also tastes good.
People will then stop eating sooner, thus reducing their chance of obesity or diabetes. The 'Dietary fibres and health' project attempts to find this information via research with test subjects.
The study, conducted by the Agrotechnology chair group at Wageningen University, aims to find out which fibres give people a feeling of fullness and how much fibre is necessary to achieve this. There are different types of dietary fibre, such as cellulose, inulin, beta glucan, and guar gum.
Dietary fibres can help prevent obesity and diabetes because they create a feeling of fullness. The Dutch Health Council recommends that adults get between 35 and 40 grams of dietary fibres per day. The problem is that this quantity is so high that it is nearly impossible to meet this requirement. On average, Dutch people eating fruit, vegetables and grains usually don’t get more than 25 grams of dietary fibres per day.
Some of these fibres end up in the large intestine, where they have an effect because they are used by bacteria in the intestines. This results in the creation of short-chain fatty acids which end up in the bloodstream, thereby creating a satiated feeling. The question is how long this feeling will last.
Other fibres bind water in the stomach, causing the stomach contents to become viscous. As a result, the stomach contents are emptied into the intestines less rapidly. The consequence of this is that the quantity of sugars in the blood remains more constant and displays fewer peaks and dips. A drop in the blood sugar level creates a hungry feeling even if there is enough food in the intestines.
The researchers are also examining the effect of physicochemical properties, such as molecular weight, load, viscosity and the bond with sugars. They are also looking at other components which bind to fibres, such as proteins.
The research is being conducted with test subjects. In the first part of the study, the subjects are given biscuits which are made with different types of fibres. They may eat as many as they like while watching a film. The researchers can determine the satiety of the different fibres from the quantity of biscuits consumed. In a different experiment, the test subjects are given standardised meals for a period of several weeks. During this period, the researchers will regularly measure the blood sugar level, hormones which are released by the intestine under the influence of fibres, and lipid metabolism in the blood.
Using the results of the study, it might be possible to modify fibres to reduce the quantity required. Food processing companies would then be able to manufacture food that tastes good and satiates.
More research: Sensory and metabolic drivers of eating behaviour