The researchers, affiliated with Maastricht University in the Netherlands and Ghent University in Belgium, wanted to provide a detailed overview specifically of the intestinal metabolism of citrus flavonoids and their interaction with the gut microbiota composition.
“Following oral ingestion, citrus flavanones reach the distal part of the small intestine and the colon almost completely intact, where they interact with the microbiota,” they reported in their paper, published recently in the journal Nutrients.
Important to keep in mind, however, was that most of the studies on the subject that have been published so far were in vitro (observations on a petri dish) or on animals.
“Therefore, more research focusing on bioavailability and on effects in human subjects may help to improve our understanding of the effects of citrus flavanones in the human gut,” they added.
The research was funded in part by BioActor BV, a Dutch functional ingredients manufacturer that makes a branded citrus extract called MicrobiomeX. Lead researcher Yala Stevens, affiliated with Maastricht University, is also head of clinical research at BioActor.
In the US, the ingredient is distributed by Seppic, a division of French chemicals giant Air Liquide.
Human clinical trial
Among the few human clinical trials included in the systematic review was one done on MicrobiomeX. It was a 12-week randomized, parallel, double-blind, placebo-controlled study on 50 overweight but otherwise healthy participants.
“The results showed MicrobiomeX anti-inflammatory activity as a result of a cross-talk between the active citrus flavonoids and the gut microbiome composition,” according to a press release circulated by BioActor announcing results of the systematic review.
“Indeed, a significant increase in the butyrate proportion of total SCFA was measured, and an almost significant reduction in calprotectin levels are signs of the positive contribution of MicrobiomeX to a balanced microbiome and host gut health.”
Worldwide, the MicrobiomeX ingredient can be found as a stand-alone ingredient in some finished products, or in combination with different probiotic strains.
Published online, doi:10.3390/nu11071464
The intestinal Fate of Citrus Flavanones and their Effects on Gastrointestinal Health
Authors: Yala Stevens, et al.