Lisa,
For this situation following the Low FODMAP diet should be helpful. Here is a list of high sulfur foods – http://www.livingnetwork.co.za/chelationnetwork/food/high-sulfur-sulphur-food-list/
Some people report benefit by supporting sulfation detoxification with the introduction of Molybdenum at 100mg to 150mg three times daily for 10 to 14 days. This trial can be worthwhile to try to see if a patient/clients symptoms improved.
Dr. Woeller