IBS Awareness Month: Understanding IBS, SIBO (Small Intestinal Bacterial Overgrowth), and the Link to Disordered Eating

Apr 23

The month of April marks IBS (Irritable Bowel Syndrome) awareness month and April 8th highlights SIBO (Small Intestine Bacterial Overgrowth) awareness day, bringing attention to two common digestive conditions.

IBS affects an estimated 5–10% of the population, and many people remain undiagnosed. It presents in three main subtypes: diarrhea-predominant (IBS-D), constipation-predominant (IBS-C), and mixed type (IBS-M). While IBS is often thought of as “just a gut issue,” it can impact far more than digestion. Many people experience disruptions in their social life, work, mental health, and their relationship with food

IBS Treatment: Symptom Management vs. Root Cause

Conventional treatment for IBS typically focuses on symptom management. This may include medications to address constipation or diarrhea, antispasmodics, antidepressants, probiotics, antibiotics, or elimination diets like the low FODMAP diet. Behavioral therapies may also be part of the plan.

While these tools can be helpful, they don’t always address the root cause of symptoms, providing temporary relief. Long-term reliance on restrictive diets or certain medications can also come with unintended consequences, particularly when it comes to gut health and nutritional adequacy.

IBS, Gut Health, and Your Relationship with Food

One of the most overlooked aspects of IBS is how deeply it can influence eating behaviors. Many individuals I work with come in following highly restrictive diets, sometimes eating only a small list of “safe” foods. While this may offer short-term symptom relief, it often comes at a cost.

Over time, restriction can negatively impact the gut microbiome, increase anxiety around food, and create or worsen patterns of disordered eating. It can also become a major barrier to healing. This is where IBS and disordered eating frequently intersect, making it challenging to introduce new foods and/or make headway in improving gut symptoms.

IBS and SIBO: What’s the Missing Piece?

For some individuals, IBS may not be the full picture. A subset of people diagnosed with IBS may actually have SIBO, or Small Intestinal Bacterial Overgrowth. Estimates suggest that anywhere from 4% to 78% of those with IBS also have SIBO. While this is a large range, it was only in late 2023 that SIBO finally landed its own diagnostic ICD code, making tracking before that challenging.

SIBO occurs when bacteria overgrow in the small intestine, where they ferment carbohydrates and trigger a wide range of digestive and systemic symptoms. You may also hear the term IMO, or intestinal methane overgrowth, which involves methane-producing organisms rather than bacteria, which are often associated with more constipation-dominant symptoms.

SIBO is not limited to IBS. Research suggests that up to 30% of individuals with inflammatory bowel disease (IBD) may also experience SIBO, highlighting how common and under-recognized this condition can be.

Recognizing SIBO Symptoms

SIBO symptoms often overlap with IBS, which is one reason it can be missed. Digestive symptoms commonly include bloating, abdominal distention, gas, belching, diarrhea, constipation, and reflux. However, symptoms are not limited to the gut.

Many people also experience brain fog, fatigue, headaches, joint pain, skin issues, and increasing food intolerances. Nutrient deficiencies, particularly vitamin B12 and iron, are also common due to impaired absorption in the small intestine. Additionally histamine issues may also be present due to the negative impacts of SIBO to the small intestine lining, where the histamine degrading enzyme DAO is made.

SIBO Testing: A Practical Approach

Testing for SIBO can be done in a few ways. While a duodenal aspirate collected during an endoscopy is considered a gold standard, it is invasive and is considerably less accessible. More often, a breath test is used, which is non-invasive and accessible.

This test typically involves a limited, specific non-fermentable diet preparation the day prior to the test, an overnight fast, and a three-hour testing window. During that time, breath samples are collected every 20 to 30 minutes. Many patients appreciate that this can be done from home, making it easier to fit into daily life.

Treating SIBO: Why a Comprehensive Plan Matters

Standard treatment for SIBO often includes prescription antibiotics such as rifaximin (Xifaxan) paired with a low FODMAP diet. While this approach can be helpful and, for some, works great, in my experience, it’s not enough! It doesn’t address the reason the gut terrain was set for overgrowth in the first place. As a result, this often leads to relapse, usually occurring within one to three months after treatment. Additionally, restrictive diets used for too long can further deplete the gut microbiome, making long-term healing more difficult.

A more comprehensive approach to SIBO looks beyond just removal. It includes:

Supporting gut motility
Addressing digestion through stomach acid, enzymes, and bile flow
Ensuring adequate nutrition, liberalizing the diet as quickly as possible
Considers the gut-brain connection
Addresses physical factors like abdominal adhesions or pelvic floor dysfunction
Considers underlying medical conditions that may impact gut motility and digestive function (Diabetes, Ehlers-Danlos Syndrome, Hypothyroid, etc.)

Equally important is addressing a person’s relationship with food. This is often overlooked but is essential, especially for those with a history of disordered eating.

Treatment is typically phased and highly individualized. Early phases focus on symptom management and/or testing, followed by targeted antimicrobial support along with nutrition, digestive support, and motility work. The final phase focuses on rebuilding and maintaining a healthy gut environment and expanding the diet as soon as possible. The timeline varies from person to person.

Eating Disorders, IBS, and SIBO: An Overlooked Connection

There is a strong connection between IBS, SIBO, and eating disorders. Research shows that individuals with gastrointestinal disorders are more likely to have disordered eating patterns compared to those without GI issues.

This relationship goes both ways. An existing eating disorder can increase the risk of developing IBS or SIBO, while chronic digestive symptoms can increase the risk of disordered eating behaviors. Even beyond remission of an eating disorder, the digestive issues can remain.

This is why screening for eating disorders is so important before recommending dietary changes, especially restrictive ones. In individuals with a history of disordered eating, elimination diets may do more harm than good. There are many tools in the toolbox for SIBO and IBS management that do not involve restrictive diets.

Not all healthcare providers are trained to recognize or manage this overlap. Working with someone who understands both gut health and eating disorder-informed care can make a difference in outcomes.

Why SIBO Keeps Coming Back

If you’ve been treated for SIBO multiple times or have been following restrictive diets for years, there is often an underlying reason why symptoms persist.

In many cases, treatment may not have fully addressed digestive function or gut motility. Some individuals may require different or repeated antimicrobial approaches. Long-term restriction can also weaken the gut microbiome and immune system, increasing susceptibility to ongoing symptoms.

It’s also important to consider that symptoms may not always be due to SIBO alone. Conditions like gut dysbiosis, fungal overgrowth, mold exposure, or other gastrointestinal infections can present in similar ways. In some cases, disordered eating patterns themselves can contribute to ongoing symptoms.

A Better Path Forward for IBS and Gut Health

If you’ve been managing IBS with medications alone and still feel stuck, it may be time to take a more comprehensive approach. True gut healing goes beyond symptom suppression and focuses on restoring function, balance, and flexibility—both in digestion and in your relationship with food.

This process takes time and intention, but it can lead to meaningful, lasting improvements. The goal is not just fewer symptoms, but more freedom in how you eat, live, and feel.

Ready to Take the Next Step?

1:1 Personalized Nutrition Counseling can help guide you through this process in a way that is both strategic and supportive. Working with a clinician who understands IBS, SIBO, the gut-brain connection, and the impact of disordered eating can help you move forward with clarity and confidence.

If you’re ready to dig deeper and take a root-cause approach to your gut health, this is your invitation to get started.

Get Started Now

REFERENCES:

https://pmc.ncbi.nlm.nih.gov/articles/PMC11792544/

https://pmc.ncbi.nlm.nih.gov/articles/PMC10134763/

https://pubmed.ncbi.nlm.nih.gov/31923640/

https://pubmed.ncbi.nlm.nih.gov/25312748/

https://pubmed.ncbi.nlm.nih.gov/34618988/

https://pmc.ncbi.nlm.nih.gov/articles/PMC5347643/