Wheat grass juice and barley grass in supplements

Melinda Dennis MS, RDN, LDN

Q: 1. Is wheatgrass juice safe for people with celiac disease?
2. I bought a probiotic (pill form) at Sprouts Grocery. The front of bottle said “Gluten Free,” but when I read the ingredients in the back, it said contained barley grass. I have celiac disease and am very sensitive to any gluten, so I returned the product. Do you know what barley grass is?


I have combined the above 2 questions to address wheat grass juice and barley grass in supplements.

Wheat grass or barley grass (and their juices) are the young (gluten-free) grasses of the wheat or barley plant. They are different from the wheat grain or barley grain that grow on the same plant and DO contain gluten. The Food and Drug Administration will allow wheat or barley grass as an ingredient in a labeled gluten-free product, including supplements, as long as the final product contains <20 parts per million (ppm) gluten, INCLUDING the presence of any gluten due to cross contact with gluten-containing grains.1 So, technically, the probiotic supplement in question above is correctly labeled if the product contains <20ppm gluten when tested.

If a person with a gluten-related disorder wants to consume a labeled gluten-free product that contains wheat grass or barley grass, it is recommended that he/she verify the manufacturer is testing for gluten contamination using the R5 ELISA test.1,2

I personally do not recommend wheatgrass or barley grass or their juices to my patients because of this risk of cross contact between the young grass and the grain seeds. It is very difficult to guarantee that wheat or barley grass is 100% free of seeds, in other words, absolutely pure and free of gluten. Please see my updated post on FDA’s stance on labeled gluten-free wheat grass, barley grass, and their juices:

Note: there is a SEPARATE issue that involves barley as a possible growth medium for the bacteria used in probiotic supplements. To read more about how this affects the gluten-free consumer, please see references #3-5.:

  1. National Celiac Association. Ask the Dietitian. https://nationalceliac.org/celiac-disease-questions/do-wheat-grass-and-barley-grass-contain-gluten/
  2. Gluten-Free Dietitian. https://www.glutenfreedietitian.com/can-products-containing-wheat-and-barley-grass-be-labeled-gluten-free/.
  3. Thompson T, Dennis M, Emerson L. Gluten-free labeling: are growth media containing wheat, barley, and rye falling through the cracks? J Acad Nutr Diet. 2017 Sep 1. http://www.sciencedirect.com/science/article/pii/S2212267217310663
  4. A summary of the Thompson, Dennis, Emerson article: https://www.glutenfreewatchdog.org/news/study-summary-gluten-free-labeling-are-growth-media-containing-wheat-barley-and-rye-falling-through-the-cracks/
  5. National Celiac Association. Ask the Dietitian. https://nationalceliac.org/celiac-disease-questions/gliadinx-product-digestive-enzyme-supplement/

Reviewed and updated October 4, 2022.

Note: This information is provided by NCA and Melinda Dennis, NCA's Senior Consulting Dietitian. This information is meant for educational purposes and is not intended to substitute for personalized medical advice or replace any medical advice provided directly to you by your health care provider. This information can be printed and used in consultation with your physician or dietitian. No liability is assumed by NCA, Ms. Dennis or her nutrition consulting service Delete the Wheat, LLC. by providing this information.

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About Melinda Dennis MS, RDN, LDN

Melinda Dennis, Senior Nutrition Consultant for NCA, is an expert celiac dietitian and and Nutrition Coordinator for the Celiac Center at Beth Israel Deaconess Medical Center in Boston, MA. Diagnosed with celiac disease in 1990, she specializes in the nutritional treatment of patients with celiac disease and gluten-related disorders.

Melinda lectures internationally and has written extensively on the nutritional management of celiac disease including the award-winning book Real Life with Celiac Disease. Melinda was the original founder of NCA in 1993 and so it is only fitting that she comes back to us in this capacity. We are truly honored to have her on our team.