Posted May 20, 2015

Gluten Found in More Than Half of Popular Probiotic Supplements Tested

Tests of 22 popular probiotic supplements revealed that 12 contained detectable amounts of gluten, according to researchers at the Celiac Disease Center at Columbia University Medical Center. Gluten is a protein found in wheat, rye and barley that can cause bowel pain and increase the risk of cancer in people with celiac disease.

Some of the supplements found to contain gluten were labeled as gluten-free -- however, the FDA allows products containing gluten up to 20 parts per million to be labeled as gluten-free, and most of the probiotics tested contained less than this amount. Four of the supplements were found to exceed this amount. 

(See's Review of Probiotic Supplements for tests of related products.)

"We have previously reported that celiac patients who use dietary supplements have more symptoms than non-users, so we decided to test the probiotics for gluten contamination," said gastroenterologist and lead author of the study, Dr. Samantha Nazareth. 

The researchers noted that the amount of gluten found in the probiotics was unlikely to cause intestinal damage in people with celiac disease unless they took "mega-doses" of the supplements, but questioned why there was any gluten in the products at all.  They did not publish the names of the tested products. is currently testing multivitamin supplements that claim to be gluten-free for levels of gluten and offers two levels of gluten-testing for products through its voluntary Quality Certification Program. It will be checking gluten levels in "gluten-free" probiotics in its next review of these products.

To read Columbia University Medical Center's full press release, use the link below.