Massey scientists have discovered a weak link in human digestion that could revolutionise healthy eating and medical treatment for the chronically-ill.
The University?s Digesta group, a multi-disciplinary team of researchers, have for the first time been able to analyse the work of the small intestine, the principal organ of digestion and absorption.
Associate Professor Roger Lentle says that until now, the only way to understand what was going on was by mathematical simulation. His team of scientists is the first in the world to measure the extent of mixing in a section of living intestine that is kept alive in a tank that simulated normal conditions in the body. Intestine from a possum, a mammal with an intestine that was large enough to measure the mixing was used. The team used a complex system of coloured pulses of material to measure the level of mixing along with video imaging and computer software and frame-by-frame analysis to measure movements of the intestinal wall. Unlike the mathematically produced results, which indicated that mixing was poor, the small intestine was found to produce quite good levels of mixing. This was partly due to a jerky motion of the muscles in the intestinal wall that help to create a turbulent environment, and to the coiling of the small intestine inside the belly.
A key finding that is important for the design of foods is that any increase in the thickness of food within the small intestine significantly impaired mixing.
?This indicates that foods which are designed to thicken when they enter the small intestine will not mix and digest well and thus will be slower to release their load of glucose or fats,? Dr Lentle says. ?An example of a potential future application is a new drink which you may have in the morning with your bacon end eggs, which thickens when it reaches the intestine and to stops or slows absorption of the fats. Drinks could also be developed to impair the absorption of glucose and cholesterol.
The findings also bode well for sufferers of intestinal diseases including Crohn?s disease or Ulcerative Colitis. Some drugs used for treating these conditions need to stay within the small intestine, Dr Lentle says, so a drink could be formulated to take with the medicine to ensure the drug is not prematurely absorbed.
?So the medicines end up in the place where they can do most good,? Dr Lentle says. ?A further use is in getting probiotics [dietary supplements containing potentially beneficial bacteria] to the lower bowel, which is where they can do the most good, by preventing them from being killed on their way through the small intestine by mixing with bile salts?
As well as commercial applications, the research has shown for the first time that the physical form of food has the potential to slow digestion and improve glycaemic index, by influencing mixing in the small intestine rather than by simply delaying the emptying of the stomach as had previously been thought
The work was made possible when the team, based at the University?s Institute of Food, Nutrition and Human Health, developed a new electronic spatiotemporal mapping technique that to enabled them to simultaneously measure lengthwise and widthwise changes in the living intestine. Five pictures of the gut per second were captured on video and electronically processed to generate movement maps of the intestine. The findings are currently being published in the prestigious Journal of Physiology.