Mechanisms of Gulf War Illness

Inclusion Criteria: 1. Veterans 18-65 years old with GWI and chronic GI symptoms (abdominal pain, diarrhea, bloating) that started during their deployment in the Persian Gulf 2. Veterans 18-65 years old with GWI and chronic GI symptoms (abdominal pain, diarrhea, bloating) 3. increased intestinal permeability on the lactulose/mannitol permeability test (ratio \>0.07) 4. able and willing to cooperate with the study Exclusion Criteria: 1. current participation in another research protocol or unable to give informed consent 2. women with a positive urine pregnancy test or breastfeeding 3. history of inflammatory bowel disease, lactose intolerance and/or celiac sprue 4. \+ hydrogen breath test for bacterial overgrowth 5. \+ anti-endomysial antibody titer 6. use of NSAIDs 2 weeks before or during the study 7. known allergy to glutamine or whey protein 8. abdominal surgery except for removal of gallbladder, uterus, or appendix \>6 months prior to entry into the study 9. Abnormal serum BUN and/or creatinine 10. Mannitol recovery out of the normal range of 5-25 U/g 11. history of kidney disease 12. allergies to monosodium glutamate 13. current use of anti-seizure medications