Bioavailability has always been the achilles heel of polyphenols. Scientist felt they had a good handle on why these molecules exerted their health effects, but had a far less clear view of how to get them to the locations in the body where they could do the most good. The answer for many years was a practice of putting in overages in formulations, an approach that was not very tidy, and potentially more expensive than it needed to be.
A big problem for getting polyphenols to circulate systemically in the blood is where the blood goes on its circuits through the body, namely through the liver. The liver is very good at quickly metabolizing any circulating polyphenolic molecules, changing them into metabolites that by and large have lesser activity. A number of approaches are available to get the molecules into the bloodstream more effectively but they don’t necessarily address the changes that occur in the liver.
Food scientist of Hang Xiao at the University of Massachusetts Amherst is taking a different approach. Xiao recently received a four-year, $490,000 grant to study the biochemical fate of nanoemulsion-based food delivery systems in the gastrointestinal tract. Xiao’s goal is to find the optimum chemical design for these delivery systems with an aim to delivery the polyphenolic (and other) molecules they are carrying into body via the lymphatic system, thereby bypassing the all-metabolizing liver.
“The goal is to produce an emulsion to enhance bioavailability to enhance the lymphatic transport,” Xiao told NutraIngredients-USA.
“By going directly into the lymphatic system the active component would bypass the first step in the liver. After metabolism in the liver a lot of times those metabolites are less active or are subject to very rapid clearance via the urine,” he said.
Xiao said the technology could be applied to a wide variety of hard-to-absorb nutraceutical compounds. It could serve as the a new basis for functionality in food and supplements, he said. Btu it could also pose risks, which is one of the things he’ll be looking at in the research funded by the grant.
“We have to use food grade materials and we don’t think the emulsion itself will present any problems,” Xiao said. “If their bioavailability (of substances otherwise metabolized in the liver) will be greatly enhanced you could do harm. That is a possibility that we will be looking at.”
Xiao and his research colleagues will also study further the effect that the small particle size has on system performance. At the moment, this is something of a mystery, he said.
“Right now I don’t think it is completely understood how the smaller particles are taken up by the enterocytes. But based on our previous publication we do know that when the particle size decreased the uptake is enhanced,” he said.
Xiao said the nanoemulsion offers some other benefits, too. It tends to be more stable than commercially available emulsion systems, increasing shelf life. And he said the properties of the emulsion can be tweaked to deliver different properties such as a transparent emulsion for beverage systems.