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HRT and your gut

Whether or not you are on or thinking of having HRT it’s a good idea to check out what we know about how HRT affects your gut community. As women age, their production of estrogen lowers which is normal as we don’t need our reproductive system in our 50 and beyond. But estrogen also has other beneficial effects in non-reproductive parts of our body such as bone, muscle, liver, skeletal muscle, and more. When you combine this lack of estrogen with a lifestyle of reduced activity and a Western diet too high in sugar, fat and salt postmenopausal women are more susceptible to weight gain and metabolic diseases like Type 2 Diabetes. Estrogen and the microbiota also work independently of each other but when they work together they appear to regulate your weight and fat deposits.

As we age the diversity of our gut microbiota can change if we don’t nurture it. This is why there have been some suggestions that estrogen and the gut microbiota together may influence obesity, diabetes and cancer. We already know that there are certain types of bacteria that are associated with obesity. Through manipulating the gut microbiota with prebiotic fibre, diet and some probiotics we can make an obese person leaner over time. Mice studies have shown that obese mice fed with Lactobacillus and Bifidobacterium probiotics, and a high fibre diet (and exercise on a mouse wheel) lost weight and in turn improved their blood glucose levels. This can also work for humans however they are not usually as compliant as the mouse 😊 and some probiotics work with some and not others.

When it comes to HRT there have been several studies looking at infection such as urogenital infections and bacterial vaginosis in post-menopausal women and how the use of HRT has decreased these infection rates. This is because the estrogen in the HRT has increased the amount of Lactobacillus species who are the main gatekeepers of vaginal health.

There are also those studies that looked at the anatomical changes of the vagina with and without HRT. Those with HRT had fewer issues such as dryness and pain than those not on HRT. One study also looked at the differences between taking Lactobacillus orally versus those inserted in the vagina (containing estrogen and Lactobacillus). Those who took the probiotics orally and inserted both saw an increase in their Lactobacillus vaginal community and reported overall improvements with their vaginal symptoms. These types of results have also been seen in similar studies with varying results.

These studies tell the same basic story. As we age, if we don’t look after our microbiota they won’t look after us. We have to maintain a healthy high fibre diet with variety and prebiotics, and of course some exercise, to keep up the diversity of our communities. It’s your choice to go on HRT or not and so far it has been shown to be an effective treatment for women with recurring infections and improves vaginal symptoms (such as dryness).

What prebiotic fibres does Lactobacillus love?

-Galacto-oligosaccharides (GOS) which you will find in Artichoke, beans, beetroot, broccoli, chickpeas, fennel, lentils, lettuce, radicchio, onion, Black beans and Borlotti beans.


- Pectin which you will find in apples, pears, apricots, lemon, cherries, oranges, carrots (raw), green beans, sugar snap peas, zucchini, cabbage, tomato, kiwifruit, eggplant, Jerusalem artichoke and blackberries.

They may also be increased by having dark chocolate and ginseng because of the polyphenols in them. It doesn’t hurt to have some probiotic yoghurt with some of the above prebiotics in them to give the yoghurt bugs to eat on the way down.


Baker, J. M., Al-Nakkash, L., & Herbst-Kralovetz, M. M. (2017). Estrogen–gut microbiome axis: Physiological and clinical implications. Maturitas, 103, 45-53. doi:

Beroukhim, R., Mermel, C. H., Porter, D., Wei, G., Raychaudhuri, S., Donovan, J., . . . Meyerson, M. (2010). The landscape of somatic copy-number alteration across human cancers. Nature, 463(7283), 899-905. doi:10.1038/nature08822

Chen, K. L., & Madak-Erdogan, Z. (2016). Estrogen and Microbiota Crosstalk: Should We Pay Attention? Trends in Endocrinology & Metabolism, 27(11), 752-755. doi:

Muhleisen, A. L., & Herbst-Kralovetz, M. M. (2016). Menopause and the vaginal microbiome. Maturitas, 91, 42-50. doi:

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