A recent study by Nazareth, Lebwohl and Green, reported at the Digestive Disease Week conference, detected the presence of gluten in 12 of 22 probiotic products tested. Eight products with detectable levels of gluten were labelled as gluten-free. It should be noted, however, that only one of the products had gluten levels above the limit set by the FDA for labelling as gluten-free (i.e., less than 20 ppm). All the other products complied with current labelling regulations.
The detection of low levels of gluten using a more sensitive method, however, does not necessarily mean that products present any health risk to people with coeliac disease. The authors of the study themselves acknowledged that there was no risk from the one product that they found above the gluten-free labelling limit: “It is unlikely that contaminated probiotics can lead to that amount [that causes intestinal damage] unless patients are ingesting mega-doses.” Nevertheless, this product might appear to be incorrectly labelled, but without the details of the study being published we, the IPA cannot take a position.
The question that is posed in the report is: Why there is gluten in some of the products in the first place? Manufacturers do not add wheat or barley during their production process but some ingredients may carry traces of these ingredients, and thus may introduce very small amounts of gluten. To control for this, certified production ingredients can be used or, if those are not available, products should be tested using accredited labs and methods to ensure levels remain below the gluten-free labelling limit.
Probiotic bacteria require complex growth media that contain a range of ingredients but these can be controlled for the presence of gluten and other allergens. If a manufacturer chooses not to control for the presence of gluten, its products cannot be guaranteed as gluten-free. It is normal practice that only products labelled as gluten-free can be expected to be gluten-free.
The International Probiotics Association (IPA), acting as the probiotic industry ombudsman, is committed to substantiated probiotic products with science at the forefront. In that respect IPA is open to working with Dr. Green and the Celiac Disease Center at the University of Columbia in order to understand the findings and explore into more detail the results. However for IPA to comment accurately on the research, we would require further information in regards to the work, such as the products that were affected, additional excipients, dosage forms, and other such pertinent information as to properly evaluate.