How female hormones affect gut symptoms
A couple of weeks ago we had a guest blog from Eloise Charleson about the influence of the gut microbiome on female hormones.
This week, we are going to switch things around and look at how female hormones affect gut symptoms.
The fact that functional gut disorders such as irritable bowel syndrome are so much more common in women than men (1.5 to 3 x higher in women), gives us a hint that ovarian hormones influence our gut health. Women also suffer with IBS symptoms most from the teenage years until the mid-40s, when levels of ovarian hormones drop off.
Similarly, around 30% of otherwise asymptomatic women experience gut symptoms around the time of their period. The effect is even stronger in women with IBS with 40% reporting that symptoms are influenced by their menstrual cycle.
It’s also worth noting that IBS symptoms tend to differ between the sexes, with men more likely to experience diarrhoea and women more likely to experience pain and bloating. Oestrogen may contribute to pain perception and higher visceral sensitivity in women than men. However the relationship between oestrogen and pain perception is dynamic and complex, GI symptoms over the course of the cycle appear to be linked to a sudden drop in oestrogen levels.
If this blog had a theme tune it would be “Sometimes it’s hard to be a woman”, but there are a few high points in the ebb and flow where the gut settles down and we are able to suggest some things you can do to help improve symptoms when they are at their worst… so read on and let’s take a look at what’s going on across the menstrual cycle and across a woman’s life.
Across the ovarian cycle - what to expect
Follicular Phase - Days 1 to 14
This is the phase from the start of your period until ovulation.
Abdominal symptoms expecially pain are often most pronounced during menstruation at the beginning of the follicular phase when oestrogen and progesterone are at their lowest. Even women without IBS often experience symptoms at this time.
Researchers believe that there is likely an association between IBS and other pelvic pain disorders such as dysmenorrhea (very painful periods). These conditions often coexist and it has been suggested that this is mediated through the effects of ovarian hormones on mast cells in the immune system, but further research is needed to fully understand the mechanism.
The good news is that later in the follicular phase after the end of menstruation, symptoms are typically much less. Progesterone is low during this phase, and gut transit times are normal.
Some studies indicate that fluctuations in oestrogen, progesterone, prostaglandins, and luteinizing hormone at the time of ovulation can alter gut motility, water retention, bloating and the sensitivity of the intestines leading to a brief increase in IBS symptoms for some women.
Luteal Phase - Days 15 to 28
This is the second half of your cycle from ovulation until the start of your period.
Progesterone and oestrogen levels start to steadily increase after ovulation. The progesterone in particular can slow gut transit times and constipation becomes more likely. Abdominal pain and bloating can also start to occur from the mid-luteal phase onwards. Soluble and insoluble fibre can help (try adding in some Superflora), plus magnesium-rich foods like dark chocolate, pumpkin seeds and spinach.
Symptoms typcally build further during the pre-menstrual phase. Just before menstruation, levels of progesterone and oestrogen suddenly drop, this can contribute to exacerbation of GI symptoms and bloating. The drop in progesterone combined with the rise in prostaglandins (hormone-like substances that trigger uterine contractions) causes many women to experience diarrhoea just before or at the start of their period. Pain perception also appears to be increased at this time. Drink plenty or water to ensure you stay hydrated.
A stylised diagram showing how gut symptoms typically change over the ovarian cycle - diet and lifestyle factors may change this.
Puberty: Laying the foundation for good gut health
The ovarian hormones can take a while to settle down into a regular cycle during the teenage years, with disruption to the length of the menstrual cycle and gut symptoms.
However, these years can be a great time to build good habits to promote gut health: plenty of plant foods (fruit, veggies, nut, seed and legumes) to provide soluble and insoluble fibre, regular exercise, relaxation and hydration. These all promote a healthy gut microbiome, with knock on effects for female hormones as we saw in Eloise’s blog.
Oral contraception effects
The combined contraceptive pill typically reduces abdominal symptoms, but some women still experience symptoms during menstruation likely due to the drop in hormones at this time.
Pregnancy, IBS and constipation
Women become less sensitive to pain during later pregnancy and this typically reduces visceral hypersensitivity improving the pain experienced by many women with IBS.
However, many women experience an increase in constipation and bloating during the later months of pregnancy due to rising progesterone which slows gut transit times. This effect occurs through progesterone's direct interaction with smooth muscle cells in the GI tract, altering contraction and relaxation pathways. Increasing a mix of both soluble and insoluble fibre in your diet, along with staying hydrated and taking gentle exercise like walking can help. Just out our Best Ever Poop Plan for great fibre sources.
Progesterone can also cause the esophageal sphincter, the muscle that keeps stomach acid down, to relax. This along with pressure from the growing baby can increase the risk of reflux in pregnancy.
To avoid reflux, focus on diet and lifestyle changes such as eating smaller, more frequent meals, avoiding trigger foods like spicy and fatty foods, caffeine, and carbonated drinks, and not eating for 2-3 hours before lying down or sleeping. Elevating the head of your bed can also help.
Menopause and gut symptoms
The research is a little mixed around the perimenopausal and menopausal period, but it appears that IBS prevalence peaks between the ages of 40 to 49, and the perimenopausal and menopausal period can be a difficult time for IBS symptoms.
In later life the decrease in ovarian hormones, particularly oestrogen after menopause mostly leads to a decrease in IBS symptoms.
However, some researchers have reported an increase in gas and excessive flatulence in post-menopausal women. The prevalence of constipation also tends to increase as we age.
Oh joy!
HRT and IBS
There is a suggestion that HRT can lead to new gut symptoms and increase incidence of IBS.
It may also prolong and worsen symptoms in women who already have the condition. If you experience this, you should discuss it with your doctor who may suggest management strategies or adjust your HRT to help control symptoms.
Takeaways:
Whilst many people look to their diet as a trigger for symptoms, consider that they may also be caused by hormone changes. Keeping a diary tracking symptoms may help you spot patterns.
Being aware of your cycle and how that influences your gut can help to prepare you for symptoms and potentially reduce them with diet and lifestyle measures, like increased soluble and insoluble fibre, water and exercise when constipation is likely, and decreased caffeine and increased soluble fibre when you expect diarrhoea.
Chat to your doctor about other ways to manage symptoms including changes to medication.
References:
Mulak, A., Taché, Y., & Larauche, M. (2014). Sex hormones in the modulation of irritable bowel syndrome. World journal of gastroenterology, 20(10), 2433–2448. https://doi.org/10.3748/wjg.v20.i10.2433
Coquoz, A., Regli, D., & Stute, P. (2022). Impact of progesterone on the gastrointestinal tract: a comprehensive literature review. Climacteric : the journal of the International Menopause Society, 25(4), 337–361. https://doi.org/10.1080/13697137.2022.2033203
Wald, A., Van Thiel, D. H., Hoechstetter, L., Gavaler, J. S., Egler, K. M., Verm, R., Scott, L., & Lester, R. (1981). Gastrointestinal transit: the effect of the menstrual cycle. Gastroenterology, 80(6), 1497–1500. https://pubmed.ncbi.nlm.nih.gov/7227774/
Heitkemper, M. M., & Chang, L. (2009). Do fluctuations in ovarian hormones affect gastrointestinal symptoms in women with irritable bowel syndrome?. Gender medicine, 6 Suppl 2(Suppl 2), 152–167. https://doi.org/10.1016/j.genm.2009.03.004
Blog written by: Noisy Guts co-founder Dr Mary Webberley. Mary has a background in biology, with two degrees from the University of Cambridge and post-doctoral research experience.