Resistant starch type-4 intake alters circulating bile acids in human subjects

• Published in: Frontiers in Nutrition Vol. 9; p. 930414
• Main Authors: Dhakal, Samitinjaya, Dey, Moul
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media SA 20.10.2022; Frontiers Media S.A
• Subjects: algorithms; Bifidobacterium adolescentis; bile; biochemical pathways; biosynthesis; circulating bile acid; class; deoxycholic acid; dietary fiber; genes; humans; metabolic syndrome; metabolomics; microbiome; microbiota; Nutrition; Nutrition. Foods and food supply; nutritional intervention; prebiotics; principal component analysis; resistant starch; resistant starch type 4; species; taurocholic acid; TX341-641; circulating bile acid; metabolic syndrome; microbiota; dietary fiber; metabolomics; resistant starch type 4
• ISSN: 2296-861X; 2296-861X
• DOI: 10.3389/fnut.2022.930414

Resistant starch (RS) type 4 (RS4) is a type of RS, a class of non-digestible prebiotic dietary fibers with a range of demonstrated metabolic health benefits to the host. On the other hand, bile acids (BA) have recently emerged as an important class of metabolic function mediators that involve host-microbiota interactions. RS consumption alters fecal and cecal BA in humans and rodents, respectively. The effect of RS intake on circulating BA concentrations remains unexplored in humans. Using available plasma and stool samples from our previously reported double-blind, controlled, 2-arm crossover nutrition intervention trial (Clinicaltrials.gov: NCT01887964), a liquid-chromatography/mass-spectrometry-based targeted multiple reaction monitoring, and absolute quantifications, we assessed BA changes after 12 weeks of an average 12 g/day RS4-intake. Stool BA concentrations were lower post RS4 compared to the control, the two groups consuming similar macronutrients ( = 14/group). Partial least squares-discriminant analysis revealed distinct BA signatures in stool and plasma post interventions. The increased circulating BA concentrations were further investigated using linear mixed-effect modeling that controlled for potential confounders. A higher plasma abundance of several BA species post RS4 was observed (fold increase compared to control in parenthesis): taurocholic acid (1.92), taurodeoxycholic acid (1.60), glycochenodeoxycholic acid (1.58), glycodeoxycholic acid (1.79), and deoxycholic acid (1.77) (all, < 0.05). Distinct microbiome ortholog-signatures were observed between RS4 and control groups (95% CI), derived using the Piphillin function-prediction algorithm and principal component analysis (PCA) of pre-existing 16S rRNA gene sequences. Association of with secondary BA such as, deoxycholic acid (rho = 0.55, = 0.05), glycodeoxycholic acid (rho = 0.65, = 0.02), and taurodeoxycholic acid (rho = 0.56, = 0.04) were observed in the RS4-group, but not in the control group (all, > 0.05). Our observations indicate a previously unknown in humans- RS4-associated systemic alteration of microbiota-derived secondary BA. Follow-up investigations of BA biosynthesis in the context of RS4 may provide molecular targets to understand and manipulate microbiome-host interactions.