Researchers tested whether the Mediterranean diet—a way of eating based on foods from countries around the Mediterranean Sea—could help people with irritable bowel syndrome (IBS), a condition that causes stomach pain, bloating, and digestive issues. In a 6-week study with 139 people in the UK, those who followed the Mediterranean diet experienced more symptom relief than those who received standard dietary advice. About 62% of people on the Mediterranean diet felt significantly better, compared to 42% on standard advice. This suggests the Mediterranean diet could be a simple, first-line treatment option for IBS instead of more complicated diets.

The Quick Take

  • What they studied: Does the Mediterranean diet work better than standard dietary advice for helping people with irritable bowel syndrome feel better?
  • Who participated: 139 people with IBS from across the United Kingdom, average age 40 years old, mostly women (80%). All participants had similar symptom severity at the start.
  • Key finding: After 6 weeks, 62% of people eating the Mediterranean way felt significantly better compared to only 42% following standard advice—a meaningful 20-percentage-point difference that was statistically significant.
  • What it means for you: If you have IBS, trying the Mediterranean diet may help reduce your symptoms more effectively than general dietary advice. However, this was a short 6-week study, so we don’t yet know if benefits last longer. Talk to your doctor before making major dietary changes.

The Research Details

This was a randomized controlled trial, which is considered one of the strongest types of research. Researchers randomly assigned 139 people with IBS into two groups: one group (68 people) followed the Mediterranean diet for 6 weeks, while the other group (71 people) received traditional dietary advice. The Mediterranean diet focuses on eating lots of vegetables, fruits, whole grains, legumes, nuts, olive oil, and fish, with limited red meat and processed foods.

Participants were recruited online through a virtual platform in the United Kingdom. Researchers measured symptom improvement using a standardized scale called the IBS Symptom Severity Scale, which asks people to rate their symptoms. They also looked at other factors like mood, quality of life, and how satisfied people were with their diet.

The study was designed as a ’noninferiority’ trial, meaning researchers wanted to show that the Mediterranean diet was at least as good as standard advice, and ideally better. This is a smart approach because it sets a realistic bar for comparison.

Using a randomized controlled trial design is important because it helps prove that the diet itself—not other factors—caused the improvement. By randomly assigning people to groups, researchers reduce bias. The fact that this study was published in a major medical journal (Annals of Internal Medicine) suggests it met high scientific standards. Testing the Mediterranean diet is particularly valuable because it’s already known to be healthy for the heart and overall health, so if it also helps IBS, people get multiple benefits.

Strengths: This was a well-designed randomized trial with clear measurement tools and similar groups at the start. The results were statistically significant, meaning they’re unlikely to be due to chance. Weaknesses: The study only lasted 6 weeks, so we don’t know if benefits continue longer. All participants were from the UK and mostly women, so results might not apply equally to men or other populations. The study was relatively small (139 people), which limits how much we can generalize. There was no long-term follow-up data.

What the Results Show

The main finding was clear: the Mediterranean diet worked better than standard dietary advice for reducing IBS symptoms. Specifically, 62% of people following the Mediterranean diet achieved a significant improvement (defined as at least a 50-point reduction on the symptom severity scale), compared to 42% of those receiving standard advice. This 20-percentage-point difference was statistically significant, meaning it’s unlikely to have happened by chance.

When researchers looked at the actual symptom scores, the Mediterranean diet group improved by an average of 101 points on the symptom scale, while the standard advice group improved by 65 points. That’s a difference of about 37 points in favor of the Mediterranean diet. In practical terms, this means people on the Mediterranean diet experienced noticeably less stomach pain, bloating, and other IBS symptoms.

Another important finding was that people following the Mediterranean diet actually stuck with it and increased their adherence to Mediterranean eating patterns over the 6 weeks, as measured by a specific scoring tool. This suggests the diet was practical and sustainable for these participants.

Interestingly, the two groups showed similar improvements in other areas. There were no significant differences in mood changes, reports of other body symptoms, quality of life improvements, or satisfaction with their diet between the two groups. This suggests that while the Mediterranean diet was superior for IBS symptoms specifically, both approaches had similar effects on mental health and overall well-being. This is actually good news because it means the Mediterranean diet doesn’t have hidden downsides in these areas.

This research builds on earlier small pilot studies suggesting the Mediterranean diet might help IBS. This larger, more rigorous trial confirms those initial findings. The results are particularly important because current medical guidelines recommend standard dietary advice as the first-line treatment, with a more restrictive diet called the low-FODMAP diet reserved for people who don’t improve. The low-FODMAP diet is complicated and requires professional guidance. This study suggests the Mediterranean diet could become a simpler first-line option that’s easier for people to follow and understand.

The study had several important limitations. First, it only lasted 6 weeks, so we don’t know if the benefits continue for months or years. Second, all participants were from the United Kingdom and 80% were women, so the results might not apply equally to men or people from other countries with different food cultures. Third, the study was relatively small (139 people), which limits how confident we can be about applying these results to larger populations. Fourth, there was no long-term follow-up, so we don’t know what happens after people stop the study. Finally, the study didn’t compare the Mediterranean diet to the low-FODMAP diet directly, so we can’t say which is better.

The Bottom Line

If you have IBS, the Mediterranean diet appears to be a reasonable first-line dietary approach to try, with moderate-to-good confidence based on this study. It’s simpler than the low-FODMAP diet and has other health benefits for your heart and overall health. Start by gradually increasing vegetables, fruits, whole grains, legumes, nuts, and olive oil while reducing red meat and processed foods. Give it at least 4-6 weeks to see if it helps your symptoms. However, because this was a short study, expect to monitor your symptoms over a longer period to see if benefits last.

This research is most relevant for people with confirmed IBS who are looking for dietary ways to manage their symptoms. It’s particularly useful for those who want to avoid complicated diets or who are interested in eating patterns that benefit overall health. People with other digestive conditions should talk to their doctor before trying this approach. Pregnant women, people with allergies to Mediterranean diet foods, and those with other medical conditions should consult healthcare providers before making major dietary changes.

Based on this study, you might notice symptom improvement within 2-4 weeks, with more noticeable benefits by 6 weeks. However, individual responses vary. Some people may see benefits faster, while others might need 8-12 weeks. It’s important to give the diet a fair trial of at least 4-6 weeks before deciding if it’s working for you.

Want to Apply This Research?

  • Track your IBS symptoms daily using a simple 1-10 scale for pain, bloating, and bowel regularity. Record what you ate each day to identify which Mediterranean diet foods help most. Aim to see a trend of decreasing symptom scores over 4-6 weeks.
  • Start by adding one Mediterranean diet element each week: Week 1 add more vegetables, Week 2 add olive oil and nuts, Week 3 add fish twice, Week 4 add whole grains, Week 5 add legumes. This gradual approach helps your digestive system adjust and makes the change less overwhelming.
  • Create a weekly symptom summary comparing your average daily scores to the previous week. Take photos of your meals to track Mediterranean diet adherence. Set reminders to eat fish twice weekly and to include vegetables at each meal. Review your progress monthly to see if symptoms continue improving or if adjustments are needed.

This research suggests the Mediterranean diet may help manage IBS symptoms, but it is not a substitute for professional medical advice. IBS is a complex condition with many potential causes, and what works for one person may not work for another. Before making significant dietary changes, especially if you have IBS or other digestive conditions, consult with your doctor or a registered dietitian. This study lasted only 6 weeks, so long-term effects are unknown. If your symptoms worsen or don’t improve after 4-6 weeks of dietary changes, seek medical attention. This information is for educational purposes and should not replace personalized medical guidance.