Eating “gluten-free” is at the height of gastronomic trendiness, but some new data may put the skids to the big eating fad.

Scientists at the the University of Illinois at Chicago have discovered a gluten-free diet may increase the risk of arsenic and mercury exposure.

Gluten-free refers to a diet that eschews any gluten, that protein found in wheat, barley, rye, and many of the by-products of these grains. For people suffering from the autoimmune condition, celiac disease, there is no choice but to adhere to a strict gluten-free diet, else risk intestinal damage. But a 2012 survey indicated that a good 28 to 30 percent of the population followed a gluten-free diet for its perceived health benefits. The new threat of arsenic and mercury poisoning is poised to toss a monkey wrench into that line of thinking.

The danger is premised upon the common use of rice flour as a gluten substitute in many gluten-free products. As the study's co-author Maria Argos noted, that rice can bioaccumulate arsenic, mercury, and other potentially harmful toxic metals from water, soil, or fertilizers.

The researchers examined the data of 7,471 individuals who were a part of the National Health and Nutrition Examination Survey between 2009 and 2014. In all these cases, the levels of toxic metals found were much higher among subjects who followed a gluten-free diet than those who did not eat gluten-free products. Arsenic levels in urine were almost twice as high, while mercury levels were 70 percent higher in the blood of gluten-free subjects.

All these data added up to what the scientists described as the "unintended consequences of eating a gluten-free diet."

"With the increasing popularity of gluten-free diets, these findings may have important health implications since the health effects of low-level arsenic and mercury exposure from food sources are uncertain but may increase the risk for cancer and other chronic diseases,” the report notes

“Although we can only speculate, rice may be contributing to the observed higher concentrations of metal biomarkers among those on a gluten-free diet as the primary substitute grain in gluten-free products."

The scientists also pointed out that Europe has much stricter regulations on their books regarding arsenic than does the US.

"We regulate levels of arsenic in water, but if rice flour consumption increases the risk for exposure to arsenic, it would make sense to regulate the metal in foods as well," the study notes.

The study has been published in Epidemiology.