Diagnosing sorbitol intolerance
The symptoms of sorbitol intolerance are unspecific; they correspond not only to the symptoms of fructose intolerance and lactose intolerance, but also to those of histamine intolerance, celiac disease, wheat sensitivity, intolerance to FODMAPs, and sometimes even to the symptoms of food allergies.
When experiencing various symptoms, keeping a food diary may be helpful to the patient's physician. If sufferers avoid sorbitol for a few days and feel better during this time, this may be evidence to support a sorbitol intolerance diagnosis.
Hydrogen breath test (as with lactose and fructose intolerances)
If the patient is suspected of having a sorbitol intolerance, a physician can perform a hydrogen breath test. The patient usually drinks 10 grams of sorbitol on an empty stomach. This dose is lower than that of lactose or fructose in the tests for lactose intolerance and fructose malabsorption because humans basically only tolerate small amounts of sorbitol.
If the patient suffers from a sorbitol intolerance, the absorbed sorbitol is not transported away in the small intestine, but moves into the large intestine. There, it is first converted to fructose and then further broken down. When the fructose is metabolized, hydrogen is produced and released by the body through the breath, and higher hydrogen content in the breath indicates a sorbitol intolerance. The principle of the test is the same as in the tests for fructose malabsorption or lactose intolerance. The range between normal and pathological in the sorbitol test is significantly narrower, however. A sorbitol test would catch most people's presence of sorbitol, even those that are perfectly healthy.