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The effect of dietary glutamate on fibromyalgia and irritable bowel symptoms
Kathleen F Holton1, Douglas L Taren, Cynthia A Thomson
1Departments of Orthopaedics and Rehabilitation, Oregon Health & Science University, Portland, OR 97239-3098, USA. holtonk@ohsu.edu
Objectives:
To examine the effects of a challenge with monosodium glutamate (MSG) as compared to placebo on the symptoms of fibromyalgia (FM), in participants who initially experienced >30% remission of symptoms on an excitotoxin elimination diet.
Methods:
Fifty-seven FM patients who also had irritable bowel syndrome (IBS) were placed on a 4-week diet that excluded dietary additive excitotoxins including MSG and aspartame. Thirty-seven people completed the diet and 84% of those reported that >30% of their symptoms resolved, thus making them eligible to proceed to challenges. Subjects who improved on the diet were then randomised to a 2-week double-blind placebo-controlled crossover challenge with MSG or placebo for 3 consecutive days each week. The primary outcome measure was total symptom score. Secondary outcome measures included visual analogue pain scales (VAS for FM and IBS), an IBS Quality of Life Questionnaire (IBS QOL) and the Fibromyalgia Impact Questionnaire-Revised (FIQR). Repeated measures ANOVA was used to analyse crossover challenge results.
Results:
The MSG challenge, as compared to placebo, resulted in a significant return of symptoms (total symptom score, p<0.02); a worsening of fibromyalgia severity as determined by the FIQR (p<0.03); decreased quality of life in regards to IBS symptoms (IBS QOL, p<0.05); and a non-significant trend toward worsening FM pain based on visual analogue scale (VAS, p<0.07).
Conclusions:
These findings suggest that dietary glutamate may be contributing to FM symptoms in some patients. Future research on the role of dietary excitotoxins in FM is warranted.
Insights
Monosodium glutamate (MSG) challenge worsened fibromyalgia symptoms and quality of life in patients who previously improved on an excitotoxin elimination diet. Dietary glutamate may contribute to fibromyalgia symptoms.
Area of Science:
- Nutrition Science
- Clinical Medicine
- Rheumatology
Background:
- Fibromyalgia (FM) is a chronic condition characterized by widespread pain and fatigue.
- Dietary factors, including excitotoxins like monosodium glutamate (MSG), are increasingly investigated for their role in symptom exacerbation.
- Excitotoxin elimination diets have shown promise in managing FM symptoms for some individuals.
Purpose of the Study:
- To investigate the impact of monosodium glutamate (MSG) challenge versus placebo on fibromyalgia (FM) symptoms.
- To assess symptom changes in patients who achieved significant symptom remission on an excitotoxin elimination diet.
Main Methods:
- Fifty-seven FM patients with irritable bowel syndrome (IBS) underwent a 4-week diet excluding excitotoxins.
- Thirty-seven participants achieving >30% symptom improvement were randomized to a double-blind, placebo-controlled crossover challenge with MSG or placebo.
- Primary outcome: total symptom score. Secondary outcomes: pain (VAS), IBS Quality of Life (IBS QOL), and Fibromyalgia Impact Questionnaire-Revised (FIQR).
Main Results:
- MSG challenge significantly increased total symptom scores compared to placebo (p<0.02).
- MSG challenge worsened fibromyalgia severity (FIQR, p<0.03) and decreased IBS-related quality of life (IBS QOL, p<0.05).
- A trend towards increased FM pain with MSG was observed (VAS, p<0.07).
Conclusions:
- Dietary glutamate, in the form of MSG, appears to trigger or worsen fibromyalgia symptoms in susceptible individuals.
- These findings highlight the potential role of dietary excitotoxins in the pathophysiology of FM.
- Further research into dietary excitotoxins and their impact on FM is warranted.
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