Clinical Trial Examining Effects of Monosodium Glutamate (MSG) on Irritable Bowel Syndrome (IBS) and Fibromyalgia (FM)

Objective: Randomized, double blind, placebo-controlled, crossover, clinical trial to examine the effects of the food additive glutamate (in the form of MSG) on IBS and fibromyalgia. Setting and Subjects: The Fibromyalgia Research Database at OHSU will be utilized to identify and recruit fibromyalgia patients who also have IBS to OHSU study centers. Intervention: Approximately 60 male and female subjects aged 18-75 will be placed on a 1-month glutamate-free elimination diet. Those that respond positively to the diet (we are estimating 30-40 subjects), will then be randomized to receive either a citrus drink containing 5 grams of MSG; or placebo (the citrus drink alone)on three consecutive days one week apart. The investigators are hypothesizing that those who react positively to the elimination diet will have symptom occurrence statistically more frequently when given the glutamate challenge, than when given placebo.