A systematic literature review of the effect of anthocyanins on gut microbiota populations.

BACKGROUND

Evidence has shown that anthocyanins, a subclass of polyphenol, are metabolised in the gut, modulate bacterial species and exert bioactive effects through this interaction.

METHODS

A systematic literature review was undertaken to determine the level of current evidence for the association between anthocyanin intake and changes in gut microbiota populations. The studies included were also assessed for the different techniques used in microbiota determination. Following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, scientific databases, including Scopus, PubMed, ScienceDirect, Web of Science and MEDLINE, were searched up to June 2017. Details on population/sample, study design, intervention/control, dosage and method of microbiota determination were extracted.

RESULTS

Six studies (three in vitro, two animal and one human trials) were included in the review, which showed that anthocyanins induced a significant proliferative effect on Bifidobacterium spp., known for their wide use in probiotics and for the treatment of irritable bowel syndrome. There was also an observed inhibition of Clostridium histolyticum, which was shown to be pathogenic in humans. The depth of analysis is an important consideration for the choice of microbiota determination technique with respect to a comprehensive, high-resolution microbiota analysis or analysis of the main microbiota taxa.

CONCLUSIONS

Very limited research has been carried out in the area of anthocyanins and gut microbiota; beneficial effects have generally been observed, and further clinical trials in humans are needed to confirm changes to gut microbes in relation to dietary anthocyanin intake and potential health benefits.