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

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

A Clinical Trial Examining the Effects of the Food Additive Glutamate on Irritable Bowel Syndrome and Fibromyalgia

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.

Glutamate challenge: After the one month glutamate free diet, subjects will receive 5 grams of glutamate for three days on one week and placebo for three days on the next week. Arm 1 is the 5 grams of glutamate which will be given in a mixed juice.

Glutamate challenge: After the one month glutamate free diet, subjects will receive 5 grams of glutamate for three days on one week and placebo for three days on the next week. Arm 2 is the placebo arm, which will be juice with nothing added.

All subjects will follow a diet for one month where all foods containing the additive glutamate have been removed. At the end of the one month diet, subjects who have responded positively to the diet will go onto the challenge arms of the study, where they will be randomized to receive placebo (mixed juice alone) for three days on one week, and 5 grams of glutamate in the mixed juice for three days on the other week.

To evaluate the number of patients who have a positive response to a one month glutamate free diet, as measured by the Perception of Global Impression of Change (PGIC) scores

To assess whether symptoms return with MSG challenge statistically more frequently than with placebo as measured by symptom scores.

A reduction in pain based on two visual analog scales, one for gut pain, and another for musculo-skeletal pain

Inclusion Criteria: Men and women aged 18-75 who fulfill criteria for Irritable Bowel Syndrome (IBS) and Fibromyalgia (FM) They must live in the greater Portland, OR, metro area, have transportation to/from study site, have access to email Willing to discontinue medications with bowel altering side effects Exclusion Criteria: Asthma Inflammatory bowel disease Colon cancer or active endometriosis Any major abdominal surgery (excluding caesarean section, tubal ligation, hernia repair, gall bladder removal or appendectomy) Female and pregnant Currently taking pregabalin, gabapentin, or anti-psychotic medications and are unwilling/ unable to discontinue use Suffered from alcohol/substance abuse or psychosis in the last two years.

Holton KF, Taren DL, Thomson CA, Bennett RM, Jones KD. The effect of dietary glutamate on fibromyalgia and irritable bowel symptoms. Clin Exp Rheumatol. 2012 Nov-Dec;30(6 Suppl 74):10-7. Epub 2012 Dec 14.