Compositional and functional differences in human gut microbiome with respect to equol production and its association with blood lipid level: a cross-sectional study

Abstract

Background Gut microbiota affects lipid metabolism interactively with diet. Equol, a metabolite of isoflavones produced by gut bacteria, may contribute substantially in beneficial lipid-lowering effects. This study aimed to examine equol production-related gut microbiota differences among humans and its consequent association with blood lipid levels. Results Characterization of the gut microbiota by deep shotgun sequencing and serum lipid profiles were compared between equol producers and non-producers. Gut microbiota differed significantly at the community level between equol producers and non-producers (P = 0.0062). At the individual level, 32 species associated with equol production were identified. Previously reported equol-producing related species Adlercreutzia equolifaciens and Bifidobacterium bifidum showed relatively higher abundance in this study in equol producers compared to non-producers (77.5% vs. 22.5%; 72.0% vs. 28.0%, respectively). Metabolic pathways also showed significant dissimilarity between equol producers and non-producers (P = 0.001), and seven metabolic pathways were identified to be associated with the equol concentration in urine. Previously reported equol production-related gene sequences in A. equolifaciens 19450T showed higher relative abundance in equol producers than in non-producers. Additionally, we found that equol production was significantly associated with the prevalence of dyslipidemia, including a marginal increase in serum lipids (27.1% vs. 50.0%, P = 0.02). Furthermore, equol production was not determined by intake of soy isoflavones, which suggested that gut microbiota is critical in the equol production process. Conclusion Both content and functioning of the microbial gut community significantly differed between equol producers and non-producers. Further, equol producers showed lower prevalences of dyslipidemia, which suggests the important role that equol might play in lipid metabolism by gut microbiota. Electronic supplementary material The online version of this article (10.1186/s13099-019-0297-6) contains supplementary material, which is available to authorized users.

Bacterial Colonization and Th17 Immunity are Shaped by Intestinal Sialylation in Neonatal Mice

“…Our findings also indicate that ⍺2,6-sialyl ligands support the key isoflavone-producing species Adlercreutzia, the presence of which is associated with improved blood lipids and reduced dietinduced obesity 108,109 . We also show a role for ST6GAL1 expression in suppressing the colonization of Helicobacter and Bilophila species, which are collectively implicated in causing infection, cancer, and metabolic dysfunction 95,96,110 .…”

Integrative Analysis of Fecal Metagenomics and Metabolomics in Colorectal Cancer

“…Adlercreutzia is a bacterium known to produce equol from isoflavonoids consumed in the diet [57], and considered to be the most contributing bacterium to equol levels in host. Equol presence in the host is also associated with lower dyslipidemia levels and higher levels of high-density lipoprotein-cholesterol [58], thus suggesting a role for these bacteria in the host's health. Equol has also been inversely associated with CRC risk in prospective studies [59], so that the increased abundance of Adlercreutzia in AD samples and its reduction in CRC patients could also be associated to this fact.…”

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“…A recent cross‐sectional study has described for the first time the overall difference (both composition and functional) in the gut microbiota between the equol‐producer and non‐producer metabotypes as well as their possible association with blood lipids. [ 189 ] Unfortunately, this study did not take into account the ODMA metabotype as an important feature of daidzein metabolism. In contrast to UMs, no significant difference in bacterial richness was found between the equol‐producer and non‐producer metabotypes.…”

“…Besides, equol‐producing related species such as Adlercreutzia equolifaciens and Bifidobacterium bifidum showed higher abundance in the equol‐producer metabotype versus the non‐producer. [ 189 ] Individuals from the equol‐producer metabotype showed a lower prevalence of dyslipidemia than non‐producers (27% vs 50%), and some microbes were statistically associated with serum lipids. However, these authors did not find any association between microbial composition and functionality with BMI, smoking habit, age, and gender.…”

“…The only difference was obviously associated with the production of equol. [ 189 ] Overall, causal conclusions regarding the involvement of the microbiota cannot be obtained from a cross‐sectional design.…”