I’m really excited to share some of the main root causes of IBS symptoms as summarised by an excellent research paper recently published by naturopathic doctor, Benjamin Brown. This paper highlights identifiable and more importantly, TREATABLE causes of IBS.
By targetting an individual’s root cause of IBS we can tailor a nutritional programme to address their specific needs. This can potentially provide improved symptom management or even resolution of symptoms in the long-term which can be life-changing. I know this to be true from my own experience with IBS-D.
Side note: In conventional medicine, IBS is purely a label for a cluster of symptoms (such as abdominal cramps and a change in bowel habits). It is a “diagnosis by exclusion”, as it is only diagnosed after excluding other pathologies such as inflammatory bowel diseases (for example Coeliac, Crohn’s and microscopic colitis). The IBS diagnosis tells us nothing about the underlying cause. In functional medicine we’re interested in the underlying pathology so that we can identify and address the root cause. So, does IBS really exist? Not really! And that’s because IBS can have a different root cause in different people, meaning it isn’t simply a standalone condition.
ROOT CAUSES OF IBS SYMPTOMS
- Nickel allergy: If you have a nickel allergy you’ll notice an itchy rash when wearing nickel containing jewellery or if you come into contact with nickel-containing coins, zips and buttons etc. For those with a nickel allergy, the ingestion of nickel (via food) causes an inflammatory response in the small intestines, just like it does on the skin. Inflammation in the gut is a key feature of IBS. Check out my blog post here all about nickel allergy and IBS, and how to reduce your intake of nickel to lower gut inflammation.
- Intestinal hyper-permeability: the lining of the intestines is selectively permeable (i.e. it only allows certain substances across such as nutrients and immune messengers whilst preventing other substances such as food particles from crossing into the bloodstream). The intestinal lining can become “leaky” (known as “leaky gut”), triggering inflammation. Intestinal hyper-permeability can be caused by food intolerances, medications, infections and chronic stress. Intestinal hyper-permeability contributes to low-grade inflammation and increased pain sensitivity, again key features of IBS. Factors influencing intestinal hyper-permeability include viral, bacterial, dietary and environmental toxins.
Intestinal hyper-permeability can be caused by food intolerances, medications, infections and chronic stress. Intestinal hyper-permeability contributes to low-grade inflammation and increased pain sensitivity which are key features of IBS
- Vitamin D deficiency: Vitamin D is important for immune function. There is a high prevalence of vitamin D deficiency in those with IBS compared to healthy adults. Vitamin D deficiency can contribute to inflammation of the gut lining, intestinal hyperpermeability and gut dysbiosis (an imbalance in the healthy bacteria living in the gut, another feature of IBS) .
There is a high prevalence of vitamin D deficiency in those with IBS
- Food hypersensitivity: food intolerances may play a role in the development of gastrointestinal symptoms due to triggering inflammation in the gut. A food intolerance involves a heightened, delayed and often long-lasting but less severe immune response than a food allergy. The most common food sensitivities tend to be dairy, gluten and eggs. Symptoms of food hypersensitivity can be systemic, which means that they can include the whole body not just the gut such as headaches, muscle and joint pain, eczema, acne, fatigue and respiratory problems.
Gut microbiome imbalance
- Small intestinal bacterial overgrowth (SIBO): Our gut is home to an abundance of micro-organisms such as bacteria, viruses, parasites and fungi, many of which play an important role in our immune system, metabolism, detoxification and regulating inflammation. Most of the bacteria live in the large intestine with much less living in the small intestine.
- SIBO is the abnormal growth of bacteria in the small intestines. Commonly, patients with SIBO experience nausea, abdominal cramping, bloating, flatulence, and diarrhoea, symptoms of IBS-D. The prevalence of SIBO in IBS patients is between 19-37%. Constipation may also be linked to SIBO although it is thought to involve the overgrowth of different bacteria compared to diarrhoea-dominant SIBO.
- There are many risk factors for SIBO including poor digestion, immunodeficiency, hypothyroidism, diabetes, physical abnormalities from abdominal surgery, medications and poor gut motility.
The prevalence of small intestinal bacterial overgrowth in IBS patients is between 19-37%
- Parasitic infection: A Blastocystis infection may be an overlooked cause of IBS symptoms in some individuals. There is a high rate of Blastocystis in IBS patients. Blastocystis can cause inflammation in the gut and intestinal hyper-permeability.
- Gut dysbiosis: a lack of beneficial bacteria and an increase in pathogenic (“bad”) bacteria in the gut can activate an immune response, increasing inflammation in the gut, setting the stage for intestinal hyperpermeability and increased sensitivity to pain in the gut. Levels of the beneficial bacterium Bifidobacterium tend to be low in patients with IBS.
Levels of the beneficial bacterium Bifidobacterium tend to be low in patients with IBS
- Pancreatic insufficiency: the pancreas produces digestive enzymes which break down protein, carbohydrate and fats in the gut so that we can absorb nutrients from our food. Pancreatic insufficiency is the inadequate production of digestive enzymes which results in poor digestion of food and absorption of nutrients. This can result in inflammation, malabsorption, intestinal hyperpermeability and gut dysbiosis. All of these factors can cause symptoms of IBS. Pancreatic insufficiency is assessed via stool testing which measures pancreatic elastase.
- Bile acid malabsorption (BAM): bile is produced by the liver and stored in the gallbladder, it contains bile acids, which are critical for the digestion and absorption of fats and fat-soluble vitamins in the small intestine. Once they’ve served their purpose, bile acids should be reabsorbed in the colon. Unabsorbed or excessive bile acids which reach the colon pull water into the colon, causing diarrhoea by speeding up gut motility. BAM is linked to a lack of beneficial bacteria in the colon and poor digestion and absorption of fat, specific areas we can target for symptom improvement.
Bile acid malabsorption is linked to a lack of beneficial bacteria in the colon and poor digestion and absorption of fat, specific areas we can target for symptom improvement
- Lactose intolerance and fructose/carbohydrate malabsorption:
- Lactose intolerance is the inability to digest lactose, a type of sugar found in milk due to a lack of an enzyme called lactase. This results in diarrhoea and wind.
- Fructose is a monosaccharide found naturally in small quantities in fruits and some vegetables, and in much larger quantities in sweeteners and added sugars. Fructose malabsorption is the impaired ability to absorb fructose and can also result in abdominal pain and IBS-D.
- Carbohydrate malabsorption is an issue with digesting and metabolising carbohydrate-rich foods, especially those that are fermentable. You may have heard of the popular low-FODMAP diet for IBS. FODMAPs are a group of short-chain carbohydrates that are poorly absorbed in the small intestine and can cause increased gas and water in the colon in some individuals, causing IBS-D and severe bloating. Fructose and carbohydrate malabsorption are linked to a gut imbalance known as SIBO (small intestinal bacterial overgrowth) which I discussed above.
Fructose and carbohydrate malabsorption are linked to a gut imbalance known as SIBO (small intestinal bacterial overgrowth)
- Stress: psychological and physical stress can influence the gut. Cortisol, our main stress hormone can influence the main features of IBS such as sensitivity to pain, colonic motility, inflammation, intestinal-hyper-permeability and alterations in the gut microbiota. A stressed mind can equal a stressed gut!
- Sedentary lifestyle: Clinical studies have found that increasing physical activity can improve gastric (stomach) emptying, intestinal gas transit and reduce abdominal distension. Therefore being sedentary can slow down the rate at which food and gas travel through the gut and increase the amount of gas produced resulting in abdominal distension and constipation.
- Poor sleep: Adequate sleep is important for so many functions within the body such as metabolism, hormone balance, brain health and immune function to name just a few. A disruption to our sleep (circadian rhythm) can affect several aspects of gut function including gastrointestinal motility, sensitivity to pain, immune function, and intestinal permeability. For a healthier gut, we definitely need to make sure we are getting adequate sleep!
Whoa! That was a lot of technical information. If you’ve read to the end, thank you! If you’re feeling overwhelmed and thinking “How do I figure out my underlying root cause?”, firstly I apologise for overwhelming you and secondly, don’t worry! Some of these factors are interconnected and can be addressed altogether using diet and lifestyle adjustments along with supportive nutritional supplements to target your root cause/s.
A snapshot of what my therapeutic protocol for IBS might look like depending on the root cause/s:
Where to start?
My recommendation is to switch to an anti-inflammatory diet and address the lifestyle aspects first: sleep, stress reduction/management and physical movement! Doing these things will help to reduce inflammation, support healthier gut bacteria and improve bowel motility. Not everyone will need antimicrobials or antifungals but they can be helpful in certain cases where there is a bacterial or fungal overgrowth in the gut or a parasitic infection. Working with a qualified practitioner in this area is helpful to address more complex cases.
Not sure where to start with your IBS diet? You can download my low FODMAP meal plan and recipe guide below!
Get in touch if you have any questions!
Brown, B.I., 2019. Does Irritable Bowel Syndrome Exist ? Identifiable and Treatable Causes of Associated Symptoms Suggest It May Not. (3), pp.314–340.
What a fantastic blog on the symptoms of ibs. Sadly too many medical drs blame so many digestive issues as ibs. But they have no real idea how to treat those suffering from it. Thank goodness we have claire and her knowledge to help seek out the root causes from digestive problems.