The Excitotoxin Elimination Diet: A Novel Dietary Intervention for those with Fibromyalgia and Irritable Bowel Syndrome

Abstract

Fibromyalgia is a chronic pain disorder characterized by multiple symptoms including severe fatigue, headache, muscle pain, cognitive dysfunction, and paresthesias. Up to 81% of patients with fibromyalgia (FM) also suffer from irritable bowel syndrome (IBS). The objectives of this study were: 1) to evaluate the effect of a 4-week excitotoxin additive free diet on symptoms of fibromyalgia (FM) and irritable bowel syndrome (IBS), and then further, to use a randomized double blind crossover challenge to determine: 2) whether FM symptoms would return more frequently when subjects were challenged with MSG as compared to placebo, and 3) whether IBS symptoms returned upon MSG challenge more frequently than placebo. Subjects were recruited from the Portland, OR area, and attended a 2-hour group diet training session and individual clinic appointment before starting a one-month excitotoxin additive free diet. At the end of the month, subjects reporting greater than 30% symptom improvement went onto a 2-week double blind crossover challenge period where they were randomized to receive either MSG in juice for 3 days or placebo for 3 days. The following week they received whatever they did not receive the first week. Eighty-four percent of those who finished the diet reported >30% symptom improvement and pre-post diet analysis demonstrated highly significant difference scores for all major outcome measures. Total symptom scores (11.4, p<0.0001), fibromyalgia impact questionnaire-revised scores (FIQR) (22, p<0.0001), and IBS quality of life (IBS-QOL) questionnaire scores (11, p<0.0001) were all significantly reduced, as were visual analog pain (VAS) change scores for FM (5.4, p<0.0001) and IBS (4.6, p<0.0001). Challenge results demonstrated that diet responders got significantly worse when challenged with MSG as compared to placebo in most measures (total symptom score, p<0.02; FIQR, p<0.03; and IBS-QOL, p<0.05). VAS for IBS and FM both worsened, but to a lesser degree (mean change of 2.1 (p<0.19) and 2.5 (p<0.07) respectively). The majority of responders were still following the diet at 2 months post study which suggests feasibility and benefit. Results suggest that the excitotoxin additive free dietary intervention may provide significant symptom relief equal to or greater than current pharmacological strategies for fibromyalgia patients with IBS.