Patients With IBS See Long-Term Benefits From FODMAP Diet

Credit: Adobe Stock/Alexander Raths

If you’ve been diagnosed with irritable bowel syndrome (IBS), you may be familiar with the FODMAP diet — a way of eating that limits specific types of fermentable carbs that can trigger symptoms like bloating, gas and abdominal pain. But how well does this diet work long term?

A recent study examined patients who were taught the FODMAP approach by a dietitian to better understand the lasting effects on symptoms, quality of life and eating habits.

The FODMAP diet is most effective when taught by a specialist dietitian rather than attempted alone or with limited guidance. The diet has three phases:

1. Phase 1: Short-term (four to six weeks) restriction of high-FODMAP foods to reduce symptoms.
2. Phase 2: Systematic reintroduction of FODMAP groups (like lactose or fructans) to test your personal tolerance.
3. Phase 3: A personalized, long-term diet based on what you can tolerate, aiming to balance symptom control with food variety.

Ongoing education and support are key, especially when reintroducing foods and managing any symptom flare-ups.

“Active involvement of an expert dietitian is recommended not only to deliver better initial education, but also in monitoring outcomes whereby excessive restriction may be prevented, misconceptions resolved, and accurate ongoing information and education provided in the potentially misleading sea of digital information,” explained lead investigator Hannah Silva, Ph.D., associated with the Department of Gastroenterology at Monash University, Australia.

The team of investigators followed 74 people with IBS who had been educated by a gastrointestinal-focused dietitian between 2008 and 2018. On average, they were assessed seven years later (with some up to 13 years) to see how they were doing with their symptoms and diet. Most participants were in their 50s and 60s, and about two-thirds of the group were women.

At the start, everyone was taught to avoid all high-FODMAP foods. Over time, some patients worked with their dietitian to reintroduce certain foods and personalize the diet to their needs.

By the time of follow-up:

• 62% were following a personalized, modified version of the diet.
• 26% had returned to their regular (pre-FODMAP) diet.
• 12% were still avoiding all high-FODMAP foods strictly.

Interestingly, 84% were still avoiding at least one FODMAP food, but total FODMAP intake (on average) was similar to that in people without IBS — unless they were still strictly restricting, in which case intake was lower.

When it came to symptoms, 64% of patients reported they were experiencing relief, regardless of how strictly they followed the diet.

People who were still on a very strict version of the diet tended to report lower food-related quality of life — assessed using the IBS Quality of Life (IBS-QoL) questionnaire — likely because of the limitations on eating out and food variety. However, overall quality of life and IBS symptom severity were similar across all diet approaches.

Patients found that adjusting their FODMAP or fiber intake helped manage flare-ups, and fewer than one-third relied on medications for symptom control.

The long-term study provided valuable insights into how well the diet worked over time, how patients adjusted their eating habits, and how their symptoms and quality of life evolved. However, investigators noted some limitations: Memory recall may have affected results, especially regarding food triggers; those who benefited from the diet may have been more likely to participate; and the COVID-19 pandemic disrupted recruitment, reducing the number of participants and limiting certain subgroup analyses.

“Education of patients with IBS on a FODMAP diet delivered by dietitians appeared to self-empower patients and improve symptoms in the long term without compromising the overall intake of FODMAPs in the longer term,” investigators concluded. “Optimizing ongoing education strategies for participants following a FODMAP diet warrants consideration.”