ProfilingofEndogenousandGutMicrobial MetabolitestoIndicateMetabotype-Specific DietaryResponses:ASystematicReview

Abstract

Upon dietary exposure, the endogenous metabolism responds to the diet-derived nutrients and bioactive compounds, such as phytochemicals. However, the responses vary remarkably due to the interplay with other dietary components, lifestyle exposures, and intrinsic factors, which lead to differences in endogenous regulatory metabolism. These physiological processes are evidenced as a signature profile composed of various metabolites constituting metabolic phenotypes, or metabotypes. The metabolic profiling of biological samples following dietary intake hence wouldprovideinformationaboutdiet—thatis,astheintakebiomarkersandtheongoingphysiologicalreactionstriggeredbythisintake—thereby enable evaluation of the metabolic basis required to distinguish the different metabotypes. The capacity of nontargeted metabolomics to also encompass the unprecedented metabolite species has enabled the profiling of multiple metabolites and the corresponding metabotypes with a singleanalysis,decodingthecomplexinterplaybetweendiet,otherrelevantfactors,andhealth.Inthissystematicreview,wescreened345articles published in English in January 2007–July 2018, which applied the metabolomics approach to profile the changes of endogenous metabolites in thebloodrelatedtodietaryinterventions,eitherderivedbymetabolismofgutmicrobiotaorthehumanhost.Weexcludedallthecompoundsthat were directly derived from diet, and also the dietary interventions focusing on supplementation with individual compounds. After the removal of less relevant studies and assessment of eligibility, 49 articles were included in this review. First, we mention the contribution of individual factors, eithermodifiableornonmodifiablefactors,inshapingmetabolicprofile.Then,howdifferentaspectsofthedietwouldaffectthemetabolicprofiles aredisentangled.Next,theclassesofendogenousmetabolitesalteredfollowingincludeddietaryinterventionsarelisted.Wealsodiscussthecurrent challengesinthefield,alongwithfutureresearchopportunities