Are All Grains Cross Contaminated?

Are Whole Grains Like Millet, Corn and Rice Safe in a Gluten-free Diet?

By Cheryl Harris, MPH, RD, LD

Gluten-free labeling has been a sore point in the U.S. because as of now, there is no national standard.  FDA regulations state that all label claims must be truthful and not misleading, but that’s a far cry from definitive rules.

Under this proposed ruling, products containing 20 parts per million or less of gluten could be labeled “gluten-free”, and single ingredient foods, such rice, millet, corn, etc., may not be labeled as “gluten-free”, unless the the manufacturer says “All (name of the grain, flour, or seed product for sale) is gluten-free.”  A new study, “Gluten Contamination of Grains, Seeds, and Flours in the United States” questions that assumption.

The research team collected a variety of grains, seeds, beans, and flours that were NOT marked “Gluten-Free” (GF) and sent them to a lab to test for the presence of gluten.  The products highest in gluten were flours, such as soy flour, millet flour, sorghum flour, and buckwheat flour.  Soy flour had the highest levels of any flours tested, with one batch containing up to 3,000 parts per million—150 times the proposed standard for “gluten-free”.  Amaranth flour had undetectable levels, as did some of the rice flours that were tested.  Whole grains were a mixed bag.  Some batches of whole grain millet exceeded the limit set under FDA’s recommended proposed ruling of 20 parts per million, but others, such as buckwheat, amaranth, and rice were under.

Sigh . . . As a dietitian who has been recommending for years that people eat naturally gluten-free foods when possible to gain their whole-grain benefits, this is unfortunate news. This is the first study of its kind and it only looked a few different grains, so it would helpful to know more about other naturally gluten-free grains, nuts, seeds, and beans.

In light of this study, however, it makes a lot of sense to ONLY and ALWAYS purchase flours that are made in a dedicated, gluten-free facility and/or ones that are tested for the presence of gluten through the Gluten Intolerance Group of North America (GIG), which tests to 10 ppm, or the Celiac Sprue Association (CSA), which tests to 5 ppm.

It also demonstrates large potential loopholes in the proposed FDA gluten-free guidance, because it shows that naturally gluten-free grains may well not be gluten-free after processing.  As the study states, “The FDA may want to modify their proposed rule for labeling of food as gluten-free, removing the requirement that gluten-free manufacturers of inherently gluten-free grains, seeds, and flours must state on product labels that all foods of that type are gluten-free.”

What about gluten-free whole grains? Products must contain less than 5 ppm. Products must contain less than 10 ppm


Harris Whole Health offers individual sessions, family sessions and group classes to help people eat healthier and feel better! Whether you are dealing with Celiac Disease, food allergies, picky eaters, children on the Autistic spectrum, chronic illness, or if you just want to feel and look better, Cheryl can help you achieve your goals. For an appointment with Cheryl Harris, Registered Dietitian and Nutritionist, please click here or call 571-271-8742.