By testing how molecules that slow down the breakdown of fat affect digestion in human volunteers, scientists at the Institute of Food Research (IFR) in Norwich in the UK hope to find new ways to control satiety, or the feeling of fullness, an important avenue in research to address the growing problem of obesity.
The project leader is Professor Peter Wilde, an expert in investigating ways to produce foods that delay fat digestion. Wilde and others at IFR have been studying food structures for the last 20 years. This includes looking at how fats interact with other ingredients to form emulsions.
The UK’s Biotechnology and Biological Sciences Research Council (BBSRC) announced on Monday 5 September that they are awarding the project a grant of about £750,000 to find out whether specific emulsions will delay the digestion of fats eaten during meals.
The project team will also include leading experts on gut hormones, satiety, and fat digestion from the Imperial College London (ICL), the University of Leeds, and the Scottish Universities Environmental Research Centre in Glasgow.
Thanks to lifestyle and dietary factors, plus the increasing availability of cheap, convenient high energy foods, making it harder for people to balance food intake with energy expenditure, obesity and conditions linked to it such as Type 2 diabetes and heart disease is a growing problem for the UK as it is in a lot of countries around the world. One way to address this problem is to increase our understanding of the biology of satiety and hunger.
Satiety is the absence of hunger and is part of a complex process controlled by hormones that feed back signals from the digestive system. When food first enters the intestines, it encounters the duodenum, where most nutrients are absorbed.
But if the meal is large or difficult to digest, some of the nutrients pass through unabsorbed to the end of the small intestine, to the ileum. When this happens, the gut walls detect the nutrients and release hormones that signal satiety: this suppresses appetite, reduces the feeling of hunger, and slows down digestion.
Scientists working in this field are trying to find ways to use this complex signalling system as a way to treat obesity. One way to do this is to slow down the digestion of fats.
As food is broken down on its journey through the gut, the fat in it forms an emulsion with the other thinner liquids. An emulsion is a mixture of two immiscible liquids where one exists as tiny droplets suspended in the other, for example as in paint.
Wilde has already shown that in the lab it is possible to slow down the digestion of fat by coating fat droplets with plant lipids or milk proteins treated with enzymes. These molecules make the fat droplets in emulsions resistant to digestion so they travel further along the intestine before being absorbed.
Wilde told the press that:
“We now want to apply these findings to human studies so that we can determine how these molecules work and measure their effects on lipid digestion, hormone release, and food intake.”
Carrying out the tests in human volunteers will help the researchers see which approaches work, and improve their understanding of satiety.
“This will provide the information needed to design a wide variety of foods with true, verifiable satiety-controlling effects,” said Wilde.
“The next step would then be to see how well these foods performed in the long term control of weight,” he added.
Written by Catharine Paddock PhD