Overview

The goal of this clinical trial is to investigate the effect of an anti-inflammatory diet and cognitive behavioral therapy (CBT) on pain symptoms, health related quality of life and the effect on inflammatory characteristics in serum and menstruum samples as well as the effect on the gut and vaginal microbiome in women with endometriosis. In addition, we want to investigate the differences in stress (measured by hair cortisol levels), inflammatory markers in peripheral blood, menstrual effluent, and the vaginal and intestinal microbiome between persons without and with endometriosis. Participants will be randomized between standard care (control group), standard care and an anti-inflammatory diet intervention, or standard care, an anti-inflammatory diet intervention and CBT or CBT alone. Participants will follow an anti-inflammatory diet based on the Dutch Dietary Guidelines or CBT or a combination of both interventions for 12 weeks. They will receive personalized dietary advice from a dietician and recipes will be available. cognitive behavioral therapy will be administered in a total of seven individual sessions led by a psychotherapist. The content of these sessions will be psycho-education regarding pain mechanisms (and diet).

Eligibility

Inclusion Criteria:

• Confirmed diagnosis of endometriosis via ultrasound, MRI or surgery*
• NRS pain score > 4*
• Age from 17 years
• Premenopausal status
• Body Mass Index (BMI) 18-30 kg/m2
• Ability to understand the explanation about the diet intervention (DI) and CBT*
• Willing to follow the DI*
• Willing to continue their use of food supplements
• Willing to undergo CBT*
• Willing to collect menstrual effluent, and therefore willing to have two stop weeks from hormonal contraception (if applicable) during the study period.

Exclusion Criteria:

• Recurrent miscarriages (> 2)
• Eating disorder
• Diagnosed with Crohn's disease, Ulcerative Colitis, short bowel syndrome or another chronic inflammatory disease
• Self-reported celiac disease
• Vegan diet
• Smoking
• Use of immunosuppressive or psychotropic medication
• Score on FFQ > 120
• Diagnosed with severe mental disorder currently requiring treatment by psychiatrist
• NRS average score below 4 during the last month
• Participation in another intervention study
• Unable to speak Dutch or to understand the intervention
• Need for surgery during the participation in the study
• Serious pain (NRS > 4) from other origin than endometriosis
• Pregnant
• Scalp hair shorter than 4 cm
  • Only applicable to patients with endometriosis