Study shows this diet improves symptoms of irritable bowel syndrome (IBS)

The daily hassle of abdominal pain, bloating, and unpredictable bathroom trips drives many people with with irritable bowel syndrome (IBS) to search for a diet that actually works.

Between four and five percent of US adults live with irritable bowel syndrome (IBS). The go‑to plan has been the low FODMAP diet, but a restrictive menu of do‑nots can turn mealtime into math class.

A new pilot trial from the University of Michigan compares that elimination regimen to the heart‑healthy Mediterranean diet and finds that both can soothe symptoms, though with different trade‑offs.

Prashant Singh, MBBS, a gastroenterologist at Michigan Medicine, led the study.

Why food choices matter

IBS is considered a disorder of gut-brain interaction, where nerves and microbes inside the intestine over‑react to normal digestion.

That hypersensitivity means small tweaks in what you eat can translate into outsized cramps or gurgles. Scientists have long noted that patients prefer diet therapy over pills, and guidelines now place food at the center of care.

Yet no single plate helps everyone. Some people flare after wheat, others after garlic, and a few after stress alone.

Targeting patterns rather than individual ingredients has therefore become a pragmatic strategy, giving physicians a framework to test and tweak without endless trial‑and‑error meals.

A closer look at FODMAP

FODMAP stands for “fermentable oligo‑, di‑, and monosaccharides and polyols,” short‑chain carbs that gut bacteria quickly digest, producing gas that can stretch sensitive intestines.

A 2022 network meta‑analysis ranked the low FODMAP diet first for global IBS symptom relief among 13 controlled trials.

“Restrictive diets, such as low FODMAP, can be difficult for patients to adopt,” said Prashant Singh.

The drawback is complexity. Shoppers must memorize long lists, calculate portion sizes, and reintroduce foods in three labor‑intensive phases.

Concerns also linger about nutritional gaps and the potential loss of beneficial gut bugs when fermentable fibers disappear.

Mediterranean diet: flavor without fear

Enter the seafood‑and‑olive‑oil approach celebrated around the world for heart protection. The landmark PREDIMED trial cut heart attack and stroke by roughly 30 percent in high‑risk adults who ate extra‑virgin olive oil or nuts daily.

Beyond arteries, recent reviews link Mediterranean eating to a bloom of short‑chain‑fatty‑acid‑producing bacteria that dampen gut inflammation.

“This study adds to a growing body of evidence which suggests that a Mediterranean diet might be a useful addition to the menu of evidence‑based dietary interventions for patients with IBS,” noted William Chey, MD, chief of Gastroenterology at Michigan Medicine.

Researchers have wondered whether that microbiome shift could calm IBS. A 2024 Australian randomized trial found the diet feasible and tied it to lower gastrointestinal distress scores. 

Unlike low FODMAP, the Mediterranean template emphasizes inclusion over exclusion, plenty of fruits, vegetables, legumes, nuts, whole grains, fish, and olive oil, with minimal red meat and sweets.

Meals feel recognizable and communal, an advantage when family dinners or restaurant outings matter to quality of life.

Numbers behind the findings

The Michigan pilot randomized 20 adults with diarrhea‑predominant or mixed‑type IBS to four weeks of either eating style.

Seventy‑three percent of the Mediterranean group and 81.8 percent of the low FODMAP group hit the U.S. Food and Drug Administration (FDA) yardstick of a 30 percent drop in abdominal pain.

Symptom-severity scores also fell in both cohorts, though the low FODMAP arm logged a steeper average decline.

Importantly, every participant received pre‑portioned meals to maximize adherence, and dietitians verified compliance rates above 90 percent.

That control means the relief probably stemmed from the diets themselves, not random chance or inconsistent follow‑through.

Still, sample size was small, so the authors call for larger, real‑world studies before formal guidelines change.

What patients can try now

If meticulous tracking and temporary restriction feel manageable, low FODMAP may offer the fastest path to quieter bowels.

Those who dread counting apple slices or onion fragments can lean into Mediterranean staples instead, foods such as oatmeal with berries at breakfast, lentil salad drizzled with olive oil at lunch, and grilled salmon with roasted vegetables for dinner.

Either way, work with a registered dietitian familiar with IBS. Professional guidance prevents nutrient gaps, monitors symptom diaries, and designs a reintroduction schedule if you start with low FODMAP.

It also helps personalize Mediterranean patterns, ensuring adequate calcium, iron, and protein for different life stages.

Remember that stress, sleep, and movement matter too. Pair dietary tweaks with a short daily walk or breathing exercise to tap the gut–brain axis from multiple angles. Small, consistent habits often beat drastic overhauls in the long haul.

The study is published in Neurogastroenterology & Motility.

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