Although underutilized, what is emerging as one of the best ways of evaluating inflammation in the body, particularly in difficult to observe regions, is through the use of Fluorodeoxyglucose (FDG) positron emission tomography (PET). FDG is taken up in the body much like glucose and is particularly taken up in areas of inflammation where there is increased metabolism. Therefore, this technology can be used to assess inflammation, and measure the reduction in inflammation as the result of integrative interventions that target dietary modifications designed to reduce inflammation. With this proposed study, we plan to use FDG PET-MRI technology to develop a more specific and sensitive approach for evaluating areas of inflammation associated with IBS and measuring improvements in that inflammation in response to effective integrative interventions.

The typical goal of the integrative medicine approach is to develop an individualized plan to help restore homeostasis to the gastrointestinal system targeting a reduction in inflammation as an important element in helping to relieve symptoms. One of the most problematic issues though is to determine where in the GI tract the inflammation is occurring and then evaluating improvements in inflammation as any intervention proceeds.

Participants will undergo a small battery of diagnostic tests that include magnetic resonance imaging (MRI), fluorodeoxyglucose positron emission tomography (FDG-PET). A secondary goal of this study is to evaluate the utility of FDG PET-MRI for assessing reductions in inflammation in patients managed with an integrative medicine approach based upon diet and nutritional counselling.

Inclusion Criteria for IBS Subjects:

1. Age greater than 18 years old.
2. Meets the Rome III criteria for IBS: Recurrent abdominal pain or discomfort at least 3 days per month in the last 3 months associated with 2 or more of the following: 1) Improvement with defecation; 2) Onset associated with a change in frequency of stool; 3) Onset associated with a change in form (appearance) of stool.
3. Patients have no other pre-existing and active significant gastrointestinal medical, neurological, or psychological disorders as per review by the PI
4. Minor, stable health problems that should have no substantial effect on cerebral blood flow will be allowed (i.e. controlled hypertension, medication controlled diabetes) as per review by the PI.
5. Patients will be allowed to be taking medications or supplements at the initial intake, but they must be on a stable dose regimen for at least 1 month.
6. Able to give informed consent and willing to complete the study.

Inclusion criteria for Healthy Controls:

1. No significant current active medical conditions.
2. Stable medical conditions as determined by the PI are allowed.
3. No brain or body abnormalities that would affect the acquisition or analysis of the scan.

Exclusion Criteria for IBS Subjects and Healthy Controls:

1. Previous abdominal (bowel) surgery.
2. Not continuously taking antioxidants or anti-inflammatory medications ( to be reviewed by the PI.
3. No other active medical conditions potentially requiring changes in treatment regimen during the study duration.
4. Not pregnant or breast feeding
5. Enrollment in active clinical trial/ experimental therapy within the prior 30 days.
6. Subject is unable or unwilling to lie still in the scanner (i.e. due to claustrophobia or weight > 350 pounds)
7. Subject has metal in their body or other reason that they cannot undergo magnetic resonance imaging.

Subjects will be recruited only if they experience symptoms of IBS.