Effects of a low-FODMAP diet on patients with endometriosis, a prospective cohort study.

Background: Patients with endometriosis often experience bowel symptoms such as changing stool, abdominal pain and bloating similar to those associated with irritable bowel syndrome. These symptoms reduce quality of life (QoL). Visceral hypersensitivity seems to be a shared pathogenic factor. The low-FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols) diet is a known visceral hypersensitivity targeted therapy with significant reduction in bowel symptoms. The aim of this study was to evaluate the effect of low-FODMAP diet on bowel symptoms such as constipation and bloating, pain and QoL in patients with endometriosis.

Methods: The diet involved four weeks of FODMAP elimination, followed by a reintroduction-period of at least ten weeks, varying by patient. Questionnaires were sent at baseline and after these periods. The primary outcome was constipation change after the reintroduction period compared to baseline, assessed by Groningen-DeFeC-questionnaire (0-30 scale) with paired-T-test or Wilcoxon-signed-rank-test. Secondary outcomes included changes in bloating, QoL and abdominal pain, assessed by Endometriosis Health Profile-30 (EHP-30). P-value < 0,05 indicated statistical significance.

Results: Forty-seven patients were included; thirteen withdrew before starting the diet, mostly due to lack of motivation. Of the remaining 34, 24 (71%) completed the diet (i.e. following the prescribed periods) Constipation scores improved significantly after low-FODMAP diet compared to baseline from 7.0 to 5.0 (p = 0.023). There was no significant difference observed in bloating, however 53% of patients that completed the diet mentioned a decrease. The following domains of the EHP-30 improved significantly: pain (from 47.8 to 29.2 (p = 0.002)), control and powerlessness (from 69.4 to 36.7 (p = 0.000)), emotional well-being (from 45.2 to 29.2 (p = 0.001)), social support (from 46.4 to 31.3 (p = 0.0017)), self-image (from 51.2 to 40.5 (p = 0.035)), work-life (from 35.0 to 21.7 (p = 0.003)) and sexual intercourse (from 61.6 to 45.7 (p = 0.023)). 65% of patients that completed the diet mentioned a decrease in pain, especially chronic pelvic pain.

Conclusions: This study suggests the low-FODMAP diet may improve bowel symptoms and QoL in endometriosis patients motivated to follow the diet, highlighting its potential in endometriosis care. However, further research in larger populations is needed to explore factors like endometriosis type, pain intensity and dropout rates to confirm these findings.

Trial registration: ICTRP: NL-OMON28996: Feasibility study: The effect of the low FODMAP diet on women suffering from endometriosis ( https://trialsearch.who.int/Trial2.aspx?TrialID=NL-OMON28996 ) on September 13th 2019.