In a new study involving 22 top-selling probiotics, as many as 12 (or 55 per cent) had detectable gluten – a component that is strictly a no no for patients with celiac disease as it could increase their pain, bowel symptoms and could even increase their risk of cancer.
Probiotics are one of the most common forms of dietary supplements used by people looking for healthier guts as well as people suffering from celiac disease. Gluten is a protein found in wheat, rye, and barley, and it is a component of food that patients with celiac disease are required to eliminate from their diet.
The research carried out by the Celiac Disease Center at Columbia University Medical Center (CUMC) used liquid chromatography-mass spectrometry, a sensitive detection technology, to quantify gluten content. Most of the probiotics that tested positive for gluten contained less than 20 parts per million of the protein, and would be considered gluten-free by Food and Drug Administration (FDA) standards. However, four of the brands (18 per cent of the total) contained in excess of that amount.
“Many patients with celiac disease take dietary supplements, and probiotics are particularly popular,” said Dr. Samantha Nazareth, a gastroenterologist at CUMC and the first author of the study. “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 Dr. Nazareth.
More than half of the 22 probiotics were labeled gluten-free, but this had no bearing on whether or not traces of gluten were present. Two probiotics that did not meet FDA standards carried the label.
“We have been following reports in the scientific literature and news media on inaccurate labeling of nutritional supplements, and it appears that labels claiming a product is gluten-free are not to be trusted, at least when it comes to probiotics,” said Dr. Peter Green, professor of medicine and director of the Celiac Disease Center, “This is a potential hazard for our patients, and we are concerned.”
It is uncertain whether these trace amounts of gluten could cause symptoms or otherwise harm patients with celiac disease.
“We know that most patients with celiac disease only develop intestinal damage when consuming more than 10 milligrams of gluten daily, and it is unlikely that contaminated probiotics can lead to that amount unless patients are ingesting mega-doses²,” said Dr. Benjamin Lebwohl, assistant professor of medicine and epidemiology at the Celiac Disease Center and a co-author of the study.
Still, these findings raise troubling questions, Dr. Lebwohl says. “Why is there any gluten in these products? Why should the consumer pay any attention to gluten-free labeling on such products? And given the great consumer interest in probiotics, will regulatory bodies take action to protect the public?”
The study, “Widespread Contamination of Probiotics with Gluten, Detected by Liquid Chromatography-Mass Spectrometry,” will be presented by Dr. Samantha Nazareth on May 16 at Digestive and Disease Week (DDW) in Washington DC.