Gluten Contamination of Commercial Oat Products in the United States
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《新英格兰医药杂志》
To the Editor: Research published in the Journal1 and elsewhere2 strongly suggests that persons with celiac disease can consume moderate amounts of uncontaminated oats. Nonetheless, celiac disease organizations in the United States continue to advise against the consumption of oats because of concern that commercial oat products may be contaminated with wheat, barley, or rye during harvesting, transporting, milling, and processing.2 However, little information is available on the contamination of oat products in the United States. Here I report an assessment of selected brands of oats for gluten contamination.
Twelve containers of rolled or steel-cut oats, representing four different lots of each of three brands, were purchased in Massachusetts between October 2003 and March 2004. The three brands were Quaker (Chicago), selected because it is a popular brand of oatmeal in the United States; Country Choice (Eden Prairie, Minn.), because it is certified to be organic; and McCann's (Odlum Group, Naas, Ireland), because it is processed in an oats-only facility. Containers were sent unopened to an independent laboratory (Food Allergy Research and Resource Program, Lincoln, Nebr.) for analysis. Samples of oats were homogenized and analyzed in duplicate, according to instructions from the manufacturer (R-Biopharm, Darmstadt, Germany). The Ridascreen Gliadin sandwich enzyme-linked immunosorbent assay (ELISA), recently validated by the Working Group on Prolamin Analysis and Toxicity, was used for the analysis.3 This ELISA uses R5, a monoclonal antibody, that is equally sensitive to the prolamins of wheat, barley, and rye and that is insensitive to the prolamins of corn, rice, and oats.4 Internal controls for this assay include six gliadin standards of known concentration. The limit of gluten detection is 3 ppm. For this assessment, oat samples were considered gluten-free if they contained 20 ppm or less of gluten, in accordance with the current Codex limit for naturally gluten-free foods.5
The results of the analysis are presented in Table 1. On the basis of the mean gluten level in the two extractions, 3 of the 12 oat samples contained gluten levels of less than 20 ppm. The other nine samples had gluten levels that ranged from 23 to 1807 ppm. All three brands of oats had gluten levels above 20 ppm in at least two of the four samples tested. Ranges according to brand were as follows: McCann's, below the limit of detection to 725 ppm; Country Choice, below the limit of detection to 210 ppm; and Quaker, 338 to 1807 ppm.
Table 1. Gluten Content of Commercial Oat Products.
Contamination of commercial oats in the United States with wheat, barley, and rye is a legitimate concern for persons with celiac disease. None of the three brands of oats included in this assessment could be relied on to be gluten-free.
Tricia Thompson, M.S., R.D.
348 Summer St.
Manchester, MA 01944
Supported in part by a research grant from the Celiac Sprue Association.
References
Janatuinen EK, Pikkarainen PH, Kemppainen TA, et al. A comparison of diets with and without oats in adults with celiac disease. N Engl J Med 1995;333:1033-1037.
Thompson T. Oats and the gluten-free diet. J Am Diet Assoc 2003;103:376-379.
Immer U, Vela C, Méndez E, Janssen F. PWG collaborative trial of gluten in gluten-free food through "Cocktail ELISA." In: Stern M, ed. Proceedings of the 17th Meeting of the Working Group on Prolamin Analysis and Toxicity, October 3-6, 2002, London, England. Zwickau, Germany: Verlag Wissenschaftliche Scripten, 2003:23-33.
Valdés I, García E, Llorente M, Méndez E. Innovative approach to low-level gluten determination in foods using a novel sandwich enzyme-linked immunosorbent assay protocol. Eur J Gastroenterol Hepatol 2003;15:465-474.
Joint FAO/WHO Food Standards Program, Codex Committee on Nutrition and Foods for Special Dietary Uses. Draft revised standard for gluten-free foods. CX/NFSDU 98/4. July 1998:1-4. (Accessed October 19, 2004, at http://intl-spectrum.diabetesjournals.org/cgi/content/full/15/3/197.)
Twelve containers of rolled or steel-cut oats, representing four different lots of each of three brands, were purchased in Massachusetts between October 2003 and March 2004. The three brands were Quaker (Chicago), selected because it is a popular brand of oatmeal in the United States; Country Choice (Eden Prairie, Minn.), because it is certified to be organic; and McCann's (Odlum Group, Naas, Ireland), because it is processed in an oats-only facility. Containers were sent unopened to an independent laboratory (Food Allergy Research and Resource Program, Lincoln, Nebr.) for analysis. Samples of oats were homogenized and analyzed in duplicate, according to instructions from the manufacturer (R-Biopharm, Darmstadt, Germany). The Ridascreen Gliadin sandwich enzyme-linked immunosorbent assay (ELISA), recently validated by the Working Group on Prolamin Analysis and Toxicity, was used for the analysis.3 This ELISA uses R5, a monoclonal antibody, that is equally sensitive to the prolamins of wheat, barley, and rye and that is insensitive to the prolamins of corn, rice, and oats.4 Internal controls for this assay include six gliadin standards of known concentration. The limit of gluten detection is 3 ppm. For this assessment, oat samples were considered gluten-free if they contained 20 ppm or less of gluten, in accordance with the current Codex limit for naturally gluten-free foods.5
The results of the analysis are presented in Table 1. On the basis of the mean gluten level in the two extractions, 3 of the 12 oat samples contained gluten levels of less than 20 ppm. The other nine samples had gluten levels that ranged from 23 to 1807 ppm. All three brands of oats had gluten levels above 20 ppm in at least two of the four samples tested. Ranges according to brand were as follows: McCann's, below the limit of detection to 725 ppm; Country Choice, below the limit of detection to 210 ppm; and Quaker, 338 to 1807 ppm.
Table 1. Gluten Content of Commercial Oat Products.
Contamination of commercial oats in the United States with wheat, barley, and rye is a legitimate concern for persons with celiac disease. None of the three brands of oats included in this assessment could be relied on to be gluten-free.
Tricia Thompson, M.S., R.D.
348 Summer St.
Manchester, MA 01944
Supported in part by a research grant from the Celiac Sprue Association.
References
Janatuinen EK, Pikkarainen PH, Kemppainen TA, et al. A comparison of diets with and without oats in adults with celiac disease. N Engl J Med 1995;333:1033-1037.
Thompson T. Oats and the gluten-free diet. J Am Diet Assoc 2003;103:376-379.
Immer U, Vela C, Méndez E, Janssen F. PWG collaborative trial of gluten in gluten-free food through "Cocktail ELISA." In: Stern M, ed. Proceedings of the 17th Meeting of the Working Group on Prolamin Analysis and Toxicity, October 3-6, 2002, London, England. Zwickau, Germany: Verlag Wissenschaftliche Scripten, 2003:23-33.
Valdés I, García E, Llorente M, Méndez E. Innovative approach to low-level gluten determination in foods using a novel sandwich enzyme-linked immunosorbent assay protocol. Eur J Gastroenterol Hepatol 2003;15:465-474.
Joint FAO/WHO Food Standards Program, Codex Committee on Nutrition and Foods for Special Dietary Uses. Draft revised standard for gluten-free foods. CX/NFSDU 98/4. July 1998:1-4. (Accessed October 19, 2004, at http://intl-spectrum.diabetesjournals.org/cgi/content/full/15/3/197.)