Background: Our previous study on Gulf War (GW) Veterans demonstrated that gastroenteritis during deployment is a risk factor for the development of irritable bowel syndrome (IBS) after deployment. Additionally, we found that Veterans with IBS were more likely to report fatigue, joint pains, general stiffness, and headaches; symptoms that are indistinguishable from GW Illness. Gastroenteritis plays a major role in changing the gut bacteria. Gut bacteria are also known to change with travel, stress, and diet changes-factors which are relevant to the GW Veterans. In fact, changes in gut bacteria may be one of the major causes of GW Illness.

Probiotics are living organisms that are known to improve health by re-establishing a normal gut flora. Probiotics also improve inflammation. Probiotics have shown some success in the treatment of IBS in non-veterans. Probiotics should be more effective in GW Veterans than non-veterans because most of these Veterans with IBS had gastroenteritis during deployment. We propose to study the role of a novel probiotic, Bifidobacterium infantis 35624 (Align®) (BI), in the treatment of intestinal and non-intestinal symptoms of IBS (fatigue, joint pains, general stiffness, and headache). We will also study whether probiotics are effective through changing the gut bacteria and decreasing inflammation.

Study: The study will be double blind, in that during the study, neither the Veteran nor the study physician will know whether the Veteran is taking the probiotic or a placebo pill (i.e., sugar pill with no medical effects). We will recruit 80 GW Veterans with IBS who were deployed and served in Operation Desert Storm between August 1990 and March 1991. There will be a 2-week screening period to establish a baseline and to account for any degree of improvement based simply on participation in the study. Then, the Veterans will be randomly assigned to receive the study probiotic (BI) or a placebo for 12 weeks. After this treatment period, the Veterans will undergo a 4-week follow-up period. At the beginning and the end of each course of therapy, Veterans' medical history will be assessed, and they will receive a physical examination. Changes in IBS symptoms and non-intestinal symptoms (fatigue, joint pains, general stiffness, and headache) will be evaluated before and after the treatment period with standardized medical questionnaires. Additionally, blood inflammation markers (cytokines) and gut bacteria will be assessed before and after the treatment period. This will tell us if improvement in IBS was indeed because of the properties of the probiotic (BI).

Study Outcomes: Changes in IBS symptoms, non-intestinal IBS symptoms, inflammation markers, and gut bacteria will be compared in the Veterans who received the study probiotic to the Veterans who received the placebo.

Conclusion: This study will inform us whether the probiotic (BI) is effective in the treatment of IBS and non-intestinal IBS symptoms, which are indistinguishable from Gulf War Illness.