As a gut health specialist, clients frequently ask me, “But why me?”. “Why do I have IBS?”, ”What caused all these symptoms in the first place?

If you’re grappling with gut symptoms, chances are this question has crossed your mind more than once. While pinpointing the exact cause of IBS remains elusive, I’m here to share six prevalent factors that contribute to the development of Irritable Bowel Syndrome. These factors may be responsible for the onset of your symptoms.

So if you’re wondering ‘’why me?” then I hope this will help give you some answers.

Let’s begin.

(To explore more videos on IBS and digestive health, head on over to The Calm and Happy Gut YouTube channel).

Factor 1: Post-Infectious IBS following Viral Gastroenteritis

Viral gastroenteritis, commonly known as the stomach flu, can irritate and inflame the stomach and intestines. In cases of viral gastroenteritis, such as those caused by norovirus or rotavirus, persistent low-grade inflammation in the gut may lead to the development of Irritable Bowel Syndrome. This phenomenon is termed Post-Infectious IBS.

Factor 2: Gut Disruption from Bacterial Infections

Similarly, bacterial infections within the gut can trigger IBS. For example, bacteria like Campylobacter, Salmonella, or E. coli caused by food poisoning. These infections not only induce persistent low-grade inflammation but may also cause nerve damage in the gut lining, affecting gut motility and sensation.

This alters the speed at which food moves through your bowel, increasing your sensitivity to pain and irritation.

Interestingly, 6-17% of individuals with IBS who previously had normal bowel habits believe their illness began suddenly after an infection. And although estimates vary, studies suggest that around 10% of people who suffer bacterial gastroenteritis develop IBS.

Furthermore, bacterial infections like Campylobacter can alter IBS subtypes, with 50% of constipation-dominant IBS cases changing to mixed or diarrhea-dominant.

Factor 3: Impact of Early Life Stress on Digestion

Numerous studies examine the correlation between early-life stress exposure and increased susceptibility to IBS.

Why does this happen? Research shows that stressful childhood events trigger abnormal signaling from a protein called nerve growth factor, leading to IBS development. The finding uncovers a link between traumatic psychological events in childhood and lifelong health repercussions.

In addition, adverse early life events significantly impact upon many of the communication pathways within the brain-gut-microbiota axis. This axis allows for two-way interaction between the central nervous system (your brain) and the gastrointestinal tract. In IBS, this axis is seen to be dysfunctional.

If you want to learn more about the brain gut axis and its role in IBS, you can check out this post: Is a Faulty Gut Brain Connection Causing Your IBS?

Factor 4: Dysbiosis and Gut Microbial Imbalance

Recent studies indicate that an imbalance in gut bacterial communities, known as dysbiosis, may contribute to the development of IBS. Changes in gut flora can trigger low-grade inflammatory responses, activating the gut immune system and precipitating symptoms. Factors such as gastrointestinal infections and antibiotic usage can disrupt the composition of gut microbiota, potentially leading to Irritable Bowel Syndrome.

Factor 5: Hormonal Changes Post-Pregnancy

Pregnancy brings about significant hormonal changes that can impact gut function. Up to 25% of women report experiencing digestive issues after childbirth, with hormonal fluctuations contributing to the development or exacerbation of Irritable Bowel Syndrome. Many women find that their symptoms worsen during or around their menstrual cycles, further highlighting the role of hormones.

Factor 6: Influence of Chronic Stress on the Gut

Most of us know and have experienced the impact of stress on our digestive system. And whether or not you have IBS, when you experience stress, it’s not unusual to have gut symptoms. Whether this is nausea, tightness in the stomach or experiencing urgency and diarrohea. Stress and gut symptoms unfortunately go hand in hand because of the close link between your brain and your gut.

In fact more and more clinical and experimental evidence shows that IBS is a combination of irritable bowel and irritable brain.

But unlike short periods of stress, such as presenting to a room of people or sitting an exam, chronic stress persists continuously. And over time chronic stress can cause numerous issues in the digestive system. For example chronic stress can cause an imbalance of the bacteria inside of your gut, which as you’ve just learnt, can be one of the factors in developing IBS.

Stress and major life trauma are also known to worsen IBS symptoms and can have a marked impact on the sensitivity inside your intestines, the speed at which your bowel functions, and on secretion and gut permeability.

Many people can trace the onset of their symptoms back to stressful periods in their lives.

Now unfortunately with IBS, your IBS symptoms themselves can trigger stress and this can very easily lead you into what is known as the vicious stress and IBS symptom cycle.

This of course is a problem. Because the more you think about your gut symptoms, the worse they are likely to become, and therefore the more stressed you become.

So join me in this next post where I talk more about this vicious stress and IBS symptom cycle, and what you can do to finally get off it and break this cycle: Are You Stuck in the Vicious Anxiety and IBS Cycle?

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