Gluten-Free Diet May Expose You to Toxic Metals

Published in the journal Epidemiology, a study concludes that a gluten-free diet may actually pose serious health risks. According to their study, co-author Maria Argos, assistant professor of epidemiology at the University of Illinois at Chicago (UIC), and her colleagues found that those who go gluten-free may increase exposure to arsenic and mercury.

Essentially, gluten is a protein found in wheat, barley, and rye. For those who don’t eat gluten, rice flour is a viable alternative and is used in many gluten-free products. In many cases, people can’t eat gluten because they have autoimmune diseases like celiac disease. However, some people avoid gluten or limit their intake even if they’re not sensitive to it.

So, whether they have to or not, people are increasingly choosing to eat gluten-free. As a result, more people are using rice flour as a substitute. Meanwhile, Argos and her colleagues noted that rice can bioaccumulate many potentially harmful toxic metals from water, soil, or fertilizers.

Exposure to arsenic, mercury, and other toxic metals correlates with an increased risk of cardiovascular disease, cancer, and other diseases. The authors of the study conclude that “despite such a dramatic shift in the diet of many Americans, little is known about how gluten-free diets might affect exposure to toxic metals found in certain foods.”

Therefore, Argos and her team were determined to know more about the connection between gluten-free diets and exposure to toxic metals. To do so, they analyzed the data from the National Health and Nutrition Examination Survey, from 2009 to 2014, which examined 7,471 individuals. After thorough research, they identified 73 participants who followed a gluten-free diet.

Then, they took blood and urine samples to test the levels of metal toxicity among those surveyed. Once completed, the researchers found that mercury levels were 70% higher in the blood among the gluten-free subjects. As for arsenic, the toxicity levels were twice as high in the urine for those on the diet. Ultimately, the results indicate that metal toxicity is higher in subjects following the gluten-free diet than in those who eat gluten.

The researchers add that:

In Europe, regulations limit arsenic in food products. Argos suggests doing the same in the U.S, especially if rice flour consumption increases the risk for exposure to arsenic.

Since further research is still needed to determine the health risks of a gluten-free diet, seek consultation from your doctor to determine whether you should or should not remain on the diet.

More recent research has expanded on these concerns and offers guidance on how consumers can reduce potential risks without abandoning medically necessary gluten-free diets. The U.S. Food and Drug Administration (FDA) has confirmed that rice and rice-based products are a primary dietary source of inorganic arsenic in the United States, particularly for individuals who consume rice as a staple grain. Long-term exposure to inorganic arsenic has been associated with increased risks of bladder, lung, and skin cancers, as well as cardiovascular disease.

Importantly, nutrition experts emphasize that the risk is not inherent to gluten avoidance itself, but to limited dietary diversity. A 2020 peer-reviewed review published in Nutrients found that individuals on gluten-free diets often consume fewer whole grains and fiber while relying heavily on processed rice-based foods, increasing both nutritional deficiencies and toxic metal exposure.

Health professionals recommend diversifying gluten-free grains by incorporating quinoa, buckwheat, millet, amaranth, sorghum, and certified gluten-free oats, which generally contain lower arsenic levels and higher micronutrient density.

Practical mitigation strategies have also been identified. Research demonstrates that rinsing rice thoroughly and cooking it in excess water (a 6:1 water-to-rice ratio with draining) can reduce inorganic arsenic levels by up to 40–60%. Selecting rice grown in regions with lower soil arsenic concentrations—such as California, India, or Pakistan—may further reduce exposure.

The Academy of Nutrition and Dietetics stresses that gluten-free diets can be safe and nutritionally adequate when medically necessary, but should be planned with professional guidance to avoid unintended health risks.