• Estrogen is amazing

    By Dr. Jessica Brandes

    It keeps our bones strong and our tissues pliable. It keeps our minds agile and happy, and even helps regulate cholesterol. It also wanes as women get older and this decrease of estrogen is partly to blame for hot flashes, bone loss, decreased sex drive, increased health risks, mood and cognitive decline. Estrogen really is amazing and since nearly 1/3 of a woman’s life is spent in menopause, it’s important to know how to live well with less of it. That means, in our later years, gut health is more important than ever.

    The “Estrobolome”

    The gut microbiome is actually one of the key regulators of estrogen metabolism in the body. Bacteria in the gut produce beta-glucuronidase, an enzyme responsible for catalyzing many reactions, among them the deconjugation of estrogen into its active forms. Once this estrogen is free, it is taken up by the blood stream for distal distribution. If deconjugation process is ineffective, it can lead to a substantial decrease in circulating estrogen.1 In fact, the gut bacteria working to assist estrogen metabolism has its very own name: the Estrobolome.

    Bacteria & Bone Loss

    Estrogen inhibits osteoclast activity. So, when estrogen decreases, osteoclastic activity increases, leading to bone resorption and loss of bone strength.

    A 2015 study demonstrated that Bifidobacterium longum given to mice who had undergone an ovariectomies "increased bone formation, decreased bone resorption, and changed the microstructure of the femur”.Lactobacillus helveticus and L. reuteri have also demonstrated positive effects on bone mass and density under certain conditions.3,4,5

    Urinary Tract Health after Menopause

    Undesirable bacteria in the urinary tract are not fun at any time of life, but the incidence can be as high as 26% in women over 65, with 20-30% experiencing recurrence. Why? Because of estrogen. Estrogen stimulates the proliferation of Lactobacilli, reduces vaginal pH, and retards vaginal colonization of Enterobacteriaceae.

    Vaginal Health & Lactobacilli

    Vaginal lactic acid-producing bacteria (lactobacilli) have many protective roles. They help to establish vaginal eubiosis by maintaining an acidic environment and inhibiting adhesion of undesirable organisms, in part through hydrogen peroxide production.  Restoration of vaginal flora with various species and strains of lactobacilli probiotics has proven an effective strategy to support vaginal health and balance.6

    Breast Health

    Since the microbiota plays a role in regulating circulating estrogen, it made sense for researchers to look into the role the estrobolome might play in estrogen-receptor positive (ER+) reproductive health risks.

    The research determined two things: 1) biopsy-positive women had a substantially less diverse microbiome than the control group; and 2) the amount of circulating estrogen was not related to the specific composition of the microbiota suggesting that the microbiome is involved in an estrogen-independent way.7

    Based on these and other findings, it certainly appears that a diverse microbiome plays a compelling role in health and prevention.


    1. Baker JM, Al-Nakkash L, Herbst-Kralovetz MM. Estrogen-gut microbiome axis: Physiological and clinical implications. Maturitas. 2017 Sep;103:45–53.

    2.  Parvaneh K, Ebrahimi M, Sabran MR, et al. Probiotics (Bifidobacterium longum) Increase Bone Mass Density and Upregulate Sparc and Bmp-2 Genes in Rats with Bone Loss Resulting from Ovariectomy. Biomed Res Int. 2015;2015:897639.

    3. Narva M, Collin M, Lamberg-Allardt C, et al. Effects of long-term intervention with Lactobacillus helveticus-fermented milk on bone mineral density and bone mineral content in growing rats. Ann Nutr Metab. 2004;48(4):228–234.

    4. McCabe LR, Irwin R, Schaefer L, Britton RA. Probiotic use decreases intestinal inflammation and increases bone density in healthy male but not female mice. J Cell Physiol. 2013;228(8):1793–1798.

    5. Collins FL, Irwin R, Bierhalter H, et al. Lactobacillus reuteri 6475 increases bone density in intact females only under an inflammatory setting. PLoS One. 2016 Apr 8;11(4):e0153180.

    6. Ueharaa S, Monden K, Nomoto K, et al. A pilot study evaluating the safety and effectiveness of Lactobacillus vaginal suppositories in patients with recurrent urinary tract infection. Int J Antimicrob Agents.2006 Aug;28 Suppl 1:S30–S34.

    7. Goedert J, Jones G, Hua X, et al. Investigation of the association between the fecal microbiota and breast cancer in postmenopausal women: a population-based case-control pilot study. J Natl Cancer Inst. 2015 Aug;107(8):djv147.

    Klaire Labs guest author:

    Dr. Jessica Brandes

    Jessica is a board-certified Naturopathic Doctor who earned her doctorate from the CNME-accredited National College of National Medicine. A former New Yorker, Jessica did her undergraduate work at NYU. She is a member of the AANP and the OANP and holds a certification in the use of advanced IV treatments from the IIVNTP.

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