GI Symptom Related-Anxiety Drives Restrictive Eating in IBS

New research presented at Digestive Disease Week (DDW) 2025 offers novel insight into the complex relationship between diet, anxiety, and the gut microbiome in patients with irritable bowel syndrome (IBS).

Study findings were presented by Jeemin Kwon, MD, an internal medicine resident at the University of California Los Angeles David Geffen School of Medicine, and shed light on the critical role that gastrointestinal (GI) symptom–related anxiety plays in shaping dietary patterns and altering gut microbiome composition among patients with IBS.

“We are beginning to realize, even besides general anxiety disorder or depression, which definitely run comorbid with IBS and other disorders of gut brain interaction, it's really the anxiety even of having GI symptoms that plays a key role in terms of the behaviors that we see people doing to control their GI symptoms,” Kwon explained to HCPLive.

While it’s long been known that meal-related symptoms are common in IBS—affecting more than 80% of patients— Kwon says the field is now gaining clarity on what drives food avoidance behaviors. Foods high in FODMAPs, along with gluten and dairy, are widely recognized triggers, but many patients restrict their diets beyond what guidelines recommend, often without systematic reintroduction, which may negatively affect nutritional diversity and long-term gut health.

According to Kwon’s research, the key driver behind this restriction may not be symptoms themselves, but rather the anticipation or fear of symptoms.

“We were really surprised to see that it was actually the GI symptom-related anxiety, rather than the actual symptoms themselves, that drove most of that relationship between having IBS and following a restrictive diet,” she said.

The study also leveraged shotgun metagenomic sequencing to explore downstream effects on the microbiome and found notable differences in certain species abundances related to fermentation pathways as well as related reductions in pathways such as pyruvate fermentation to butanoate implying less short chain fatty acid production.

“If you think about it, it makes a lot of sense that reducing lactose and FODMAPS is going to lead to less fermentation, and that's probably why a lot of these folks have that symptom relief in terms of bloating and abdominal pain,” Kown said. “But now we're kind of raising the question, do we need to be concerned? Are there more long term negative effects in terms of what these restrictive diets are doing to our microbiome?”

Looking ahead, Kwon says future research needs to explore the hypothesis that targeting GI symptom-related anxiety in the clinical setting could be helpful for patients with IBS. She also points to the need for longitudinal data to explore the long-term effects of reductions in fermentation on gut health and a more comprehensive understanding of the gene pathways being upregulated or downregulated and how they play into the gut-brain axis for IBS.

Editors’ note: Kwon has no relevant disclosures.

Reference

1. Kwon J, Mahurkar-Joshi S, Fasulo C, et al. GI SYMPTOM-RELATED ANXIETY DRIVES RESTRICTIVE EATING IN IBS, LEADING TO GUT MICROBIOME ALTERATIONS AND POTENTIAL NEGATIVE EFFECTS ON GUT HEALTH. Abstract presented at Digestive Disease Week 2025 in San Diego, CA, from May 3 - May 6, 2025.