Skip to main content
. 2021 Jun 29;10(13):2916. doi: 10.3390/jcm10132916

Table 1.

Characteristics and summary, of studies included for research questions 1–2 (estrogen/menopause and gut microbiome).

Study Sample Size Patient Characteristics Gut Microbiota Analysis Main Findings
Zhao et al. (2019) n = 24 Premenopausal women
n = 24 Postmenopausal women		 Premenopausal:
Age (yrs) 52.6 ± 6
BMI (kg/m2) 23.1 ± 4.5
LDL (mM) 3.0 ± 0.8
Postmenopausal
Age (yrs) 53.9 ± 3.8
BMI (kg/m2) 23.0 ± 3.2
LDL (mM) 2.89 ± 0.83
No statistical differences.		 Single-end metagenomic sequencing on BGISEQ-500 platform.
Relative abundance calculation by Metaphlann2 (used by the NIH Human Microbiome Project part 2).
Alpha-diversity → Shannon-index.		 Alpha diversity (Shannon index):
Premenopausal 1.8
Postmenopausal 1.3 (p 0.000005)
Phyla:
Firmicutes:
  • -

    Premenopausal 31.6

  • -

    Postmenopausal 17.4 (p 0.00003)

Bacteroidetes:
  • -

    Premenopausal 20.1

  • -

    Postmenopausal 28.9 (p 0.003)

Gemmatimonadetes
  • -

    Premenopausal 22.5

  • -

    Postmenopausal 26.5 (p 0.03)

Spirochetes:
  • -

    Premenopausal 18.1

  • -

    Postmenopausal 30.9 (p 0.001)

Genera:
Postmenopausal state:

  • ↓ Faecalibacterium, Alistipes, Eubacterium, and Roseburia.

  • ↑ Bacteroides, Staphylococcus, Parabacteroides

Postmenopausal:
When ↑ Eubacterium rectale (stimulated by isoflavones → ability prevention dysbiosis)
Shin et al. (2019) n = 9 high estrogen women (premenopausal)
n = 8 medium estrogen women (premenopausal)
n = 9 low estrogen women (postmenopausal)		 High estrogen
(>60 pg/mL)
Age (yrs) 39.3 ± 3.2
BMI 28.9 ± 0.2
Medium estrogen:
(5–60 pg/mL)
Age (yrs) 44 ± 2
BMI (kg/m2) 26.9 ± 0.9
Low estrogen: (<5 pg/mL).
Age (yrs) 54.9 ± 1.0
BMI (kg/m2) 24.9 ± 0.5
BMI not statistically different		 16S V6 rRNA amplicon sequencing using QIIME.
Taxonomy assigned against the Greengenes 16S rRNA gene database.
Alfa diversity → Chao1 richness, Simpson evenness, Good’s coverage and Shannon diversity.		 Inline graphic
  • -

    Low estrogen 5.6

Alpha diversity (Chao1-index):
  • -

    High estrogen -6900

  • -

    Low estrogen -6500 (NS)

Phyla:
Firmicutes:
  • -

    Low estrogen 0.4

  • -

    High estrogen 0.28 (IQR; p < 0.05)

Bacteroidetes
  • -

    Low estrogen 0.58

  • -

    High estrogen 0.69 (IQR; p < 0.05)

Firmicutes/Bacteroidetes ratio
  • -

    Low estrogen 1.2

  • -

    High estrogen 0.4 (p < 0.05)

Family within Bacteroidetes phylum:
Dominant: Bacteroidaceae (61.2%), Prevotellaceae (28.6%), Rikenellaceae (3.6%)
Postmenopausal vs. premenopausal
  • ↓

    Bacteroidaceae

  • ↑

    Rikenellaceae

  • ↑

    Porphyromonadaceae

  • ↑

    Odoribacteraceae

Family within Firmicutes phylum:
Dominant: Ruminococcaceae (42.3%), Lachnospiraceae (39.9%), Veillonellaceae (11.7%).
Postmenopausal vs. premenopausal.
  • ↓

    Veillonellaceae

  • ↑

    Lachnospiraceae

Specific genera for postmenopausal status:
  • -

    No presence of Veillonella

  • -

    Enriched in Slackia, Lactococcus, Christensenella, Dehalobacterium, Adlercreutzia, Odoribacter, and Butyricimona

Link genera and serum estradiol levels.
  • -

    Drop in serum estradiol through

Slackia (r = −0.4; p 0.033)
Butyricimonas (r = −0.4; p 0.046)
Zhu et al. (2018) n = 25 premenopausal women
n = 46 postmenopausal women
(breast cancer patients excluded)		 Premenopausal
Age (yrs) 35.5 ± 6.0
BMI (kg/m2) 23.0 ± 2.0
Postmenopausal
Age (yrs) 56.9 ± 6.4
BMI (kg/m2) 24.0 ± 2.5
BMI not statistically different		 Illumina DNA sequencing.
Taxonomy calculated against the integrated reference catalog of the human gut microbiome (IGC) by bowtie2
Alfa-diversity → Shannon index, Chao index		 Alpha diversity (Shannon index)
Premenopausal 3.1
Postmenopausal 3.2 (p-value not calculated)
Alpha diversity (Chao1 index)
Premenopausal −430
Postmenopausal −415 (p-value not calculated)
Alpha diversity (OTU)
Premenopausal −400
Postmenopausal −390 (p-value not calculated)
Link genera and serum estradiol levels.
  • -

    Shewanella putrefaciens (Spearman rho = 0.379; p = 0.025)

  • -

    Erwinia amylovora (Spearman rho = 0.351; p = 0.039)
Santos-Marcos et al. (2018) n = 17 premenopausal women
n = 20 postmenopausal women		 Premenopausal
Age (yrs) 46.1 ± 0.8
BMI (kg/m2) 26.3 ± 1.5
LDL (mg/dL) 119 ± 7
Postmenopausal
Age (yrs) 55.6 ± 0.6
BMI (kg/m2) 28.9 ± 1.3
LDL (mg/dL) 137 ± 7		 Sequencing the V1–V2 microbial 16S rRNA gene on the Illumina MiSeq
Taxonomy assigned against Greengenes v13-8 database		 Phyla:
Firmicutes
  • -

    Premenopausal 44.1%

  • -

    Postmenopausal 50.7%

Bacteroidetes
  • -

    Premenopausal 48%

  • -

    Postmenopausal 43.4%

Firmicutes/Bacteroidetes ratio
  • -

    Premenopausal 1.2

  • -

    Postmenopausal 2.1 (p 0.01)

Actinobacteria phylum
  • -

    Premenopausal

  • -

    Postmenopausal (p 0.001)

Genus:
Premenopausal
  • ↑

    Parabacteroides (p = 0.002)

  • ↑

    Prevotella (p < 0.001)

  • ↑

    Bilophila

Postmenopausal
  • ↑

    Lachnospira (p = 0.047)

  • ↑

    Roseburia (p = 0.003)

Link gut microbiome and estradiol levels:
Positively correlated:
  • -

    Class Gammaproteobacteria (R = 0.575, p = 0.013)

  • -

    Family from Mixococcales (R = 0.521, p = 0.039, respectively)

Negatively correlated
  • -

    Family Prevotellaceae (R = −0.523 p = 0.018)

Immunology:
TNF-alfa (pg/mL)
Premenopausal 0.26 (±0.05)
Postmenopausal 0.38 (±0.06; NS)
IL-6 (pg/mL)
Premenopausal 1.25 (±0.15)
Postmenopausal 1.75 (±0.25; p 0.036)
MCP-1 (pg/mL)
Premenopausal 72 (±4)
Postmenopausal 94 (±7; p 0.045)
Choi et al. (2017)
Animal study 		n = 3 SHAM mice
n = 5 ovariectomized mice (OVX)		 SHAM
Weight (g) 29.96 ± 2.13
LDL (mg/dL) 30.9 ± 5.1
OVX
Weight (g) 41.44 ± 1.52
LDL (mg/dL) 45.1 ± 9.1
Weight significantly different		 V3-V4 16S rRNA amplification following the 16S Metagenomic Sequencing Library Preparation guide by Illumina.
Gene-enrichment and functional annotation analysis performed using gene ontology and KEGG pathway analysis.		 Alpha diversity (Shannon index)
  • -

    SHAM 3.3

  • -

    SHAM-HF (significant reduction)

  • -

    OVX 2.4 (significant reduction)

  • -

    OVX-HF no difference controls

Phyla
Firmicutes
  • -

    SHAM mice: 20%

  • -

    OVX mice: 90%

Bacteroidetes
  • -

    HAM mice: 78%

  • -

    OVX mice: 2%

Actinobacteria
  • -

    Increase in abundance in OVX mice

Genus and species
SHAM
  • ↑

    Prevotella (p 0.036)

  • ↑

    Bacteroides (p 0.036)

  • ↑

    Bacteroidales (p 0.036)

OVX
  • ↑

    Lactobacillus species (p 0.049)

  • ↑

    Bifidobacterium animalis (exclusively present in this group p 0.043)

Link gut microbiome and estradiol
  • -

    Gene expression of estrogen signaling pathways differed significantly between OVX and SHAM

Differences in the microbiome caused by ovariectomy similar to those caused by the high-fat diet
Zhang et al. (2017)
Animal study		 n = 6 SHAM rats
n = 12 OVX
  • -

    n = 6 OVX vehicle

  • -

    n + 6 with curcumin

 All groups:
Virgin Wistar rats
Age (yrs) 0.5
Weight: 310 ± 20.0 g
(OVX rats significantly higher weight)		 The estradiol concentration in the serum detected through electrochemiluminescence immunoassay (ECLIA) Alpha diversity (Shannon index)
  • -

    SHAM 7.0

  • -

    OVX 7.16

Phyla
  • -

    Firmicutes

  • -

    SHAM: 0.26 ± 0.05

  • -

    OVX: 0.53 ± 0.07

Bacteroidetes
  • -

    SHAM 0.66 ± 0.07

  • -

    OVX: 0.32 ± 0.11

Genus
Incertae_Sedis
  • -

    SHAM: 0.04 ± 0.00

  • -

    OVX: 0.10 ± 0.01 (p 0)

Heliobacter
  • -

    SHAM 0.03 ± 0.01

  • -

    OVX: 0.15 ± 0.051 (p 0.002)

Anaerovorax
  • -

    SHAM 0.000233 ± 0.00

  • -

    OVX 0.001323 ± 0.00 (p 0.02)

Anaerotruncus
  • -

    0.003101 ± 0.00

  • -

    0.006812 ± 0.00 (p 0.04)
Fuhrman et al. (2014) n = 6 postmenopausal women
(acting as their own controls)		 Postmenopausal
Age (yrs) 60.2 ± 3.2
BMI (kg/m2) 27.3 ± 5.4		 Pyrosequencing V1–V2 16S rRNA amplicons, QIIME: Ribosomal Data Project Bayesian classifier. Alpha diversity (Shannon index)
  • -

    Postmenopausal 6.6 ± 6.6

Phyla
Firmicutes
  • -

    Postmenopausal 63.5% (IQR 48.4–73.1%)

Bacteroidetes
  • -

    Postmenopausal 35.6% (IQR 26.4–50.4%)

Link gut microbiome to estradiol levels.
Positive correlation ratio of estrogen metabolites to parent estrogen:
  • -

    Order clostridiales (R0.32; p 0.02)

  • -

    Family Ruminococcaceae (R0.37; p 0.05).

Negative correlation ratio of estrogen metabolites to parent estrogen:
  • -

    Genus bacteroides (R-0.3; p 0.03).

Urinary estrogen (pM/mg creatinin)
Postmenopausal women 28.1 (±17.8)
Parent estrogen (estrone and estradiol 32 % of total EM’s) 2-, 4- and 16-hydroxilated metabolites represented 29%, 3% and 35%)
Flores et al. (2012) n = 19 premenopausal women
n = 7 postmenopausal women
n = 22 age matched men (55 yrs and older)		 Average BMI 26 In feces, β-glucuronidase and β-glucosidase activities were determined by real-time kinetics, and microbiome diversity and taxonomy were estimated by pyrosequencing 16S rRNA amplicons. Urinary estrogen (pM/mg creatinine):
men 82.6
premenopausal women 68.7
postmenopausal women 155.1
Levels non-ovarian estrogens
Premenopausal
  • -

    No association with alpha diversity.

Postmenopausal
  • -

    Strongly associated with fecal microbiome richness and alpha diversity

Non-ovarian urine estrogen (estrone) levels strongly and significantly associated with
Postmenopausal
  • -

    Taxa Clostridia (Firmicutes,)

  • -

    3 genera from family Ruminococcaceae (β = 0.57 to 0.70, p = 0.03 to 0.002

Premenopausal:
  • -

    Correlation premenopausal estrogens with abundance Clostridiales Firmicutes almost nil (β = −0.10, p = 0.55)

Fecal β-glucuronidase activity:
Postmenopausal
  • -

    Significantly correlated with urine estrone level (R = 0.36, p = 0.04) but not with total urine estrogens (R = 0.24, p = 0.19), estradiol (R = 0.16, p = 0.38), or EM

Premenopausal
  • -

    Urine estrogens not correlated with either β-glucuronidase or β-glucosidase activity. Activity of the control enzyme, β-glucosidase, was not related to total urine estrogens (R = 0.12) or to any of the parent estrogens or EM

Fecal estrogens in postmenopause:
  • -

    Deconjugated estrogens inversely correlated with total estrogen levels in urine; especially strong for deconjugated fecal estrone (R = −0.50, p = 0.005)

  • -

    Conjugated not correlated with urinary estrogen levels

  • -

    Fecal β-glucuronidase activity inversely correlated with both deconjugated and conjugated estrogens in feces (p ≤ 0.01 for all except 16-epiestriol)

  • -

    Shannon index and OTU species were strongly and significantly associated with lower levels of conjugated and especially deconjugated estrogens in feces