An analysis performed by researchers at the Celiac Disease Center at Columbia University Medical Center showed that more than half of popular probiotics tested contained traces of gluten. Probiotics are typically used to help promote gut health, though the evidence surrounding their benefits is limited.

Using liquid chromatography-mass spectrometry, the investigators analyzed 22 of the top-selling probiotics and found 12 of them to have detectable gluten; four of the brands contained in excess of the standard set by the Food and Drug Administration (FDA) for labeling a product gluten-free (less than 20 parts per million of the protein).

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For patients with celiac disease, ingesting gluten may increase the chance for intestinal problems; however,  researchers are uncertain as to whether these trace amounts could cause symptoms or otherwise harm patients. “Most celiac patients only develop intestinal damage when consuming more than 10 milligrams of gluten daily, and it is unlikely that contaminated probiotics can cause problems unless someone is ingesting mega-doses,” said Dr. Benjamin Lebwohl, assistant professor of medicine and epidemiology at the Celiac Disease Center and a co-author of the study.

Still, the question remains as to why these probiotics contain any gluten. More than half of the 22 products were labeled as gluten-free, but this had no bearing on whether or not traces of gluten were present. Given the increased interest in probiotics, patients with celiac disease need to be aware that the product labeling may not allows match up with the contents.

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