Clinical Trial: Effect of a 28‐Day Low FODMAP Diet on Gastrointestinal Symptoms Associated With Endometriosis (EndoFOD)—A Randomised, Controlled Crossover Feeding Study

BACKGROUND: Gastrointestinal symptoms affect most women with endometriosis, but therapeutic interventions are poorly defined. AIMS: To compare the effects of a 28-day low fermentable oligo-, di- and mono-saccharides and polyols (FODMAP) or control diet on gastrointestinal symptom severity in individuals with endometriosis and poorly controlled gastrointestinal symptoms. METHOD: In this single-blinded randomised, controlled cross-over feeding trial, we randomised women aged ≥ 18 years to 28 days of either a low FODMAP (< 5 g/day FODMAPs) or control diet (20 g/day FODMAPs), both modelled on Australian Dietary Guidelines, before a ≥ 28-day washout and crossover to the alternate diet. The primary outcome was the proportion of responders defined according to the response in overall gastrointestinal symptoms on a 100-mm visual analogue scale. Secondary outcomes included gastrointestinal symptoms, quality of life and psychological status. RESULTS: Of 35 women randomised (mean age 31; 95% confidence interval 29, 33 years), 21 (60%) responded to the low FODMAP diet compared with 9 (26%) to the control diet (p = 0.008). In the 4th week of the dietary intervention, overall symptom scores were 35 (21, 42) mm on the low FODMAP diet and 58 (55, 65) mm on the control diet (p < 0.001). Abdominal pain, bloating, stool form and quality of life for both gastrointestinal and endometriosis-associated scales were significantly better for the low FODMAP diet compared with the control diet, but not overall for perceived stress, anxiety or depression. CONCLUSIONS: The low FODMAP diet ameliorates gastrointestinal symptoms related to endometriosis and improves quality of life. Confirmation of these findings in a real-world setting is required. TRIAL REGISTRATION: The trial is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12621000153819).