From Constipation to Diarrhea: Why IBS Looks Different in Every Woman
If you’ve been diagnosed with IBS, you may have noticed that your symptoms don’t look exactly like someone else’s. Some women struggle with constipation that leaves them bloated for days, while others deal with urgent diarrhea that disrupts their daily life. And then there are those who bounce between both extremes, never knowing what to expect.
This wide variation is part of what makes IBS so confusing—and sometimes so frustrating. But functional medicine offers clarity: by understanding the different subtypes of IBS and what drives them, you can find more targeted, lasting relief.
1. The Three Main Types of IBS
Doctors classify IBS into three broad categories based on your most common bowel patterns:
IBS-C (Constipation-Predominant): Hard, difficult-to-pass stools, fewer than three bowel movements per week, and often significant bloating.
IBS-D (Diarrhea-Predominant): Frequent, loose, or watery stools, often with urgency after meals.
IBS-M (Mixed-Type): Alternating constipation and diarrhea—sometimes unpredictably.
There’s also a less common category, IBS-U (Unclassified), where symptoms don’t fit neatly into the above groups.
Understanding which type you fall into helps guide both treatment and lifestyle changes.
2. Why Constipation and Diarrhea Happen in IBS
IBS isn’t “just stress” or “just bad digestion.” At its core, IBS involves a dysregulation of gut motility and sensitivity. Here’s how it plays out differently:
Constipation (IBS-C):
Sluggish motility in the colon means stool moves too slowly.
Too much water is reabsorbed, leaving stool hard and painful to pass.
Women with IBS-C often experience bloating, fullness, and discomfort that worsen throughout the day.
Diarrhea (IBS-D):
The opposite problem: rapid motility pushes stool through too quickly.
Not enough water is absorbed, leading to loose stools and urgency.
Many women with IBS-D feel tied to the bathroom after meals due to the “gastrocolic reflex.”
Mixed (IBS-M)
A shifting gut environment and inconsistent motility create unpredictable swings between diarrhea and constipation.
This type can be especially disruptive because it’s hard to anticipate.
3. The Role of the Microbiome
A growing body of research shows that the gut microbiome—the trillions of bacteria living in your intestines—plays a key role in IBS subtypes.
IBS-C patients often show reduced levels of Bifidobacteria and microbes that produce short-chain fatty acids (important for motility) (Pozuelo et al., Gut Microbes, 2015).
IBS-D patients tend to have more opportunistic bacteria that ferment aggressively, producing excess gas and loose stools.
Dysbiosis (imbalanced bacteria) increases gut sensitivity and permeability, fueling both constipation and diarrhea symptoms.
4. Stress and the Gut–Brain Axis
Your brain and gut are in constant communication. Stress and anxiety directly affect bowel habits:
Stress increases gut sensitivity, making mild bloating or fullness feel painful.
It alters motility, sometimes slowing things down (constipation) and sometimes speeding them up (diarrhea).
Women with IBS often report that their worst flares follow stressful events—even if their diet hasn’t changed.
This explains why two women eating the same meal might have opposite reactions based on their nervous system state.
5. Hormones and Bowel Habits
Hormonal fluctuations also affect whether IBS symptoms lean toward constipation or diarrhea:
Progesterone, which rises in the luteal phase of the menstrual cycle, slows gut motility—often worsening constipation in IBS-C patients.
Prostaglandins, released during menstruation, stimulate the bowels and can worsen diarrhea in IBS-D patients (Adeyemo et al., Am J Gastroenterol, 2004).
Perimenopause and menopause shifts can magnify symptoms by altering gut microbiome diversity and motility.
6. Functional Medicine Approaches for Each IBS Subtype
Rather than giving every patient the same advice, functional medicine tailors treatment to your IBS subtype.
For IBS-C (Constipation):
Hydration + Magnesium: Magnesium citrate or glycinate can help soften stools and relax the bowels.
Fiber—but the right kind: Soluble fiber (psyllium husk) is often better tolerated than insoluble fiber (like raw bran).
Motility support: Gentle exercise, regular meal timing, and prokinetic herbs (ginger, artichoke extract).
Address SIBO: Methane-dominant SIBO is strongly linked with constipation (Rezaie et al., Am J Gastroenterol, 2017).
For IBS-D (Diarrhea):
Low-FODMAP trial: Removing fermentable carbs can reduce urgency and frequency.
Binders + soothing agents: Peppermint oil, chamomile, or partially hydrolyzed guar gum help calm spasms.
Probiotics: Certain strains (Saccharomyces boulardii, Lactobacillus plantarum) help normalize bowel frequency.
Stress reduction: Since stress directly triggers diarrhea, nervous system support is crucial.
For IBS-M (Mixed):
Identify triggers: Food journaling often reveals what flips symptoms toward constipation vs. diarrhea.
Restore microbiome balance: A combination of antimicrobial herbs and probiotics may reduce swings.
Support gut-brain axis: Mind-body practices (yoga, mindfulness) help stabilize motility.
7. Real-Life Example
Anna, a 37-year-old with IBS-M, alternated between days of no bowel movement and sudden diarrhea.
Testing showed:
Hydrogen + methane SIBO, explaining her mixed symptoms.
High stress levels and poor sleep quality.
Her plan included:
Herbal antimicrobials for SIBO.
A low-FODMAP diet with careful food journaling.
Magnesium citrate to support constipation days.
Daily yoga and mindfulness practice.
Within three months, her bowel patterns became more predictable, bloating reduced, and her energy improved.
8. Practical Tips for Every Woman with IBS
Track your symptoms: Note stool type, stress levels, meals, and menstrual cycle timing. Patterns often emerge.
Don’t assume all fiber helps: Soluble vs. insoluble fiber can make a huge difference.
Hydrate wisely: Adequate water is essential for constipation but also helps regulate diarrhea.
Work on stress: Even 5–10 minutes of deep breathing can calm the gut–brain axis.
Takeaway
IBS doesn’t look the same for everyone—and that’s why generic advice so often falls short. Whether you lean constipated, diarrheal, or both, the key is to understand your subtype and support the root causes: motility, microbiome balance, stress, and hormones.
When we stop lumping all IBS sufferers together and start personalizing care, women can finally find the relief they’ve been searching for.
👉 At Bluegrass Natural Health, we specialize in helping women identify their IBS subtype and create a tailored healing plan. Whether constipation, diarrhea, or both are holding you back, we can help uncover your triggers and restore balance. Book a free discovery call today to learn more.
📚 Selected References
Adeyemo MA et al. (2004). Menstrual cycle and symptoms in IBS. Am J Gastroenterol, 99(2): 390–396.
Pozuelo M et al. (2015). Microbiome signatures in IBS subtypes. Gut Microbes, 6(5): 279–293.
Rezaie A et al. (2017). Methane and constipation in IBS/SIBO. Am J Gastroenterol, 112(5): 775–784.
Staudacher HM et al. (2017). Low-FODMAP diet in IBS. Gastroenterology, 152(5): 1358–1364.