Doctors who practice so-called “functional” medicine look at IBS as a problem with the “ecology” of your gastrointestinal tract. You may have a bad mix of bacteria growing in your intestines, microbes such as yeast or even microscopic parasites overwhelming the usual, “friendly” microbes inhabiting your GI tract. You may have digestive enzyme deficiencies that are inhibiting proper food absorption. You could be intolerant of a food or food additive. Even some of the drugs used to treat GI disorders, like proton pump inhibitors (PPIs) used to treat GERD (heartburn) can contribute to IBS symptoms.
To figure out the right IBS diet and treatment approach, doctors who practice functional medicine do tests such as a comprehensive stool analysis–which can include an analysis of what’s growing in your guts–and food allergy testing to figure out what’s causing your symptoms. This allows them to come up with the right IBS diet and treatment regimen for you. Even a course of certain antibiotics (Rifaximin or Biaxin) can be helpful for IBS, because these drugs can knock out bad bacteria infecting your gut. But the antibiotic needs to be followed up with treatment to restore the bacterial “good guys.” Yeast overgrowth requires different treatment, with yeast-killing drugs.
You can find a doctor specializing in functional medicine at http://www.functionalmedicine.org. Click on “Find a Practitioner.”