IBS is an acronym that stands for irritable bowel syndrome. This irritation in digestive tract can greatly impact someones quality of life and is a common complaint we see in clinic.
IBS typically presents as a mix of either constipation or diarrhea and is often paired with abdominal pains, bloating, or flatulence.
What is normal?
In order to understand potential IBS triggers, knowledge of normal digestive function is key.
Even before we eat, our body is setting our system up for success by making digestive enzymes and acid in response to the smells and sights we experience while cooking. When we finally take a bite, chewing both manually grinds foods and stimulates saliva production that contains enzymes to break carbohydrates down. Swallowing then sends our food down the esophagus and into the stomach where acid and digestive enzymes await to to break it down further. From there, the small intestine is responsible for absorbing micronutrients. The large intestine sucks out all the water to form our stool and is home to our gut microbiome.
So what can lead to IBS?
Although there may be more at play and the exact causes of IBS are uncertain, I commonly encounter these four triggers in my practice:
1.) Gut Motility Issues & Mental Health
Our autonomic nervous system has two main branches, the parasympathetic (aka “rest and digest”) and sympathetic (aka “Fight or flight”). You may recall that during a period of intense stress, your bowel movements were not normal. Maybe you experienced a loose stool due to overactive nerves or were unable to pass one for multiple days. This is due to the significant impact that stress has on our vagus nerve. The vagus nerve is responsible for stimulating digestive juices and driving muscle contractions (aka peristalsis) that keep our bowels moving smoothly. When we eat on the run or do not allow our body time to calm before eating we impair our digestive function.
How we eat and when we eat can also play a role. IBS can often occur if meals are skipped, too large, or if we’re eating sporadically. Also, the plants we eat throughout the day provide us with fiber needed to regulate our bowel motility. The gut loves consistency!
Also, there is a well established bidirectional set of signals that pass between the brain and our gut tissue. Ninety percent of our serotonin is produced in the gut, so when these levels are low it can not only impact our mood but also impede peristalsis and increase sensitivity of the nerves of the gut. Addressing both mental health concerns, neurotransmitter imbalances and gut motility is an effective IBS management strategy.
2.) Microbiome Imbalances
Balance and diversity are essential when it comes to the community of bacteria, viruses, and fungi that live in our large intestine. Either insufficient or overgrown levels of these microbes can cause disruptions to bowel transit time and symptoms such as gas and bloating. Insufficiency is more common in cases of looser stools and the yeast Candida is a common culprit for those living with constipation, bloating and flatulence. Fiber is important here as well, as it not only helps to bulk up the stool but can nourish our gut bacteria.
A stool sample is the best way to gain insight into possible imbalances in the large intestine.
3.) Foods Sensitivities
When we eat foods our bodies do not tolerate well, the undigested food fragments that make their way through our GI tract activate our gut related immune system. This can cause a lot of local irritation and inflammation which serve to make the gut tissue more sensitive.
Common food sensitivities that contribute to IBS symptoms include gluten, dairy, eggs, soy, nuts, alcohol, and foods rich in FODMAPs.
FODMAPs are fermentable sugars that some individuals do not break down well. When undigested, FODMAPs draw water into the intestines resulting in looser bowel movements and increased peristalsis. FODMAPs often cause bloating from our gut microbes feasting on them and producing gas as a byproduct. Although a low FODMAP diet is not meant to be implemented long term, it can provide relief while other factors are being ruled out.
4.) Genetics & Enzyme Deficiencies
Enzyme deficiencies can be inherited. The classic example is an inability to produce lactase which is needed to break down lactose. This then leads to lactose intolerance which can trigger diarrhea, bloating, gas and abdominal pain if someone eats dairy. Sucrase, isomaltase and alpha-galactosidase can all impact ones ability to break down sugars. Supplementing with digestive enzymes or herbs to support enzyme production can be helpful in these cases.
Common medications that can worsen or trigger IBS symptoms include NSAIDs, antibiotics, antidepressants, PPIs, opioids, hormonal medications, etc.
- Patel N, Shackelford K. Irritable Bowel Syndrome. [Updated 2022 Oct 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534810/
- Wald A. Clinical Manifestations and Diagnosis of Irritable Bowel Syndrome in Adults. UpToDate. Updated July 20, 2022. Current through July 2023.