Gluten free labeled foods not always gluten free

Gluten free labeling is, sadly, not a guarantee of safety for those with celiac disease or non-celiac gluten sensitivity as demonstrated in a study recently published in the Journal of Food Protection. The authors state:

"Gluten is the main storage protein in grains and consists of gliadin and glutenin occurring in the same ratio. Persons suffering from intolerances, including celiac disease, must avoid foods containing gluten or products containing wheat, barley, and rye... This study was designed to determine the concentrations of gluten in foods labeled “gluten free” available in the United States."

Gluten found in diverse products

Many sources of gluten are far from obvious and it may not occur to question whether a product is gluten free.

"Gluten is found not only in all products made with wheat, rye, and barley but also as an ingredient in foods including meat, sausages, soups, and ready-to-eat meals. Due to its physicochemical characteristics, gluten is used in food products to modify both texture, e.g., as a thickener to improve texture and water or fat retention, and form, e.g., to increase the extensibility. Gluten can also be used as an animal protein substitute in meat products to reduce manufacturing costs. Furthermore, gluten and wheat starch are found in some drugs as a filler."

 Standards for 'Gluten Free' labeling

There is a significant difference between gluten free and ‘‘foods specially processed to reduce gluten content’’ or ‘‘very low gluten’’.

"To be labeled ‘‘gluten free,’’ products must contain less than 20 mg/kg gluten, i.e., equivalent to 10 mg/kg gliadin, while foods labeled as ‘‘foods specially processed to reduce gluten content’’ or ‘‘very low gluten’’ must comply with levels between 20 and 100 mg/kg. In October 2013, the U.S. Food and Drug Administration (FDA) issued a final rule to define the term ‘‘gluten free’’ for voluntary use in the labeling of foods. According to the final rule, gluten free means that the food bearing the claim does not contain (i) an ingredient that is a gluten-containing grain (e.g., spelt wheat), (ii) an ingredient that is derived from a gluten-containing grain and has not been processed to remove gluten (e.g., wheat flour), or (iii) an ingredient that is derived from a gluten-containing grain and has been processed to remove gluten (e.g., wheat starch) if the use of that ingredient results in the presence of 20 mg/kg or more gluten in the food, or it means that the food (iv) inherently does not contain gluten, and food with any unavoidable presence of gluten that is below 20 mg/kg gluten can be labeled as gluten free."

Cross-contamination

Cross-contamination of products inherently gluten free can occur in production, transportation and storage.

"Cross-contamination of inherently gluten-free foods can occur at all stages of the food chain, including when they are grown, harvested, and/or processed. Comingling of grain in the field can occur because of crop rotation with wheat, barley, or rye if they are grown next to or in rotation with these grains. It is possible that seeds of the gluten-containing grains will linger in the soil and, as a result, some of the gluten-containing grain may be collected during the same harvest with the inherently gluten-free grain. Sharing of storage facilities where relevant, such as in grain elevators, can result in co-mingling of grains. Further, using the same transportation vehicles for moving the grains to the processing site and sharing of processing facilities and equipment within those facilities can also result in cross-contamination. The presence of wheat in oats is a good example of on-farm cross-contamination...If cross-contamination occurs at any stage in the food chain, undeclared glutens can end up in the processed food products...A few small studies have shown that contamination may occur in gluten-free foods or inherently gluten-free grains and their milled fractions, such as oats, millet flour, and sorghum flour. In addition, gluten has been detected in rice-, corn-, oat-, and buckwheat-based foods with or without the gluten-free label. Hence, the aim of the present study was to analyze foods in the U.S. market labeled gluten free for gluten contamination."

So the authors randomly collected 78 commercially available samples labeled gluten free were from different local markets in Moscow, Idaho and analyzed them for gliadin content by competitive enzyme-linked immunosorbent assay. Their data engenders concern and vigilance for anyone who truly needs to avoid gluten:

Breakfast cereals were the most frequently contaminated

"Based on the gluten levels of samples, 48 of the 78 (61.5%) products contained gluten below the limit of quantification (less than 10 mg/kg gluten). Fourteen of the 78 (17.9%) products contained a detectable amount of gluten ranging from 10.9 to 18.7 mg/kg. Sixteen (20.5%) of the 78 would not be considered gluten free under the proposed FDA rules for gluten-free labeling. Among other parameters, foods labeled gluten free must contain <20 ppm gluten to be labeled gluten free. The gluten contamination frequency was highest in breakfast cereal (62.5%), followed by bread (37.5%), pasta (23.1%), snack food (13.3%), and baking mix (11.1%)."

Rice and corn products are attractive to those avoiding gluten but are not free of treachery:

"Being the most popular ingredients in gluten-free products, rice and corn might be considered to be safer cereal-based foods for CD patients...of the 16 gluten-contaminated samples, the most contaminated gluten-free food samples were made with rice, corn, or mixed grains, including seven rice-based foods, three corn-based foods, and six mixed-grain-based foods. Moreover, all of 6 mixed-grain-based samples included rice flour. According to our data, the most contaminated samples labeled gluten free were made from rice or corn and the levels of contamination were less than 50 mg/kg gluten."

 Gluten free mislabeling is a world-wide problem

The concern is similar for Europeans and Canadians:

"A few previous studies have examined gluten in gluten- free foods and reported cross-contamination of 14 to 22% in inherently gluten-free foods and 46% in products based on gluten-free wheat starch produced by a deglutination process. According to Valde ́s et al., a study of more than 3,000 gluten-free foods in Europe showed that one third had gluten levels higher than 20 mg/kg, which is above the gluten-free threshold. Another study reported that 5% of 1,583 different products labeled as gluten free contained gluten. In a study of Canadian cereal foods, about 10% of the 77 gluten-free foods were contaminated with gluten."

Bottom line on gluten free labeling

More rigorous standards of compliance are necessary to ensure the dependability of products labeled or presumed to be gluten free. A product such as rice or corn is being intrinsically gluten free is not sufficient to confirm that it is.

"Products made from inherently gluten-free crops that are labeled gluten free but are not tested to be gluten free may be deemed misbranded if the label implies that all inherently gluten-free crops are free of gluten, since these inherently gluten-free grains, such as rice, corn, and buckwheat, can be contaminated with gluten."

The authors conclude by recommending the measurement of gluten in all grain based products:

"Under the proposed FDA rule for labeling of foods as gluten free, manufacturers who voluntarily choose to label their single-ingredient grain products as gluten free will have to imply to consumers that since all inherently gluten-free grains, such as rice, corn, millet, buckwheat, and sorghum, are gluten free by nature, their products using these grains are gluten free; this does not guarantee, though, that there will be no gluten contamination. ...Statements such as ‘‘all millet is gluten free’’ can be misleading and potentially harmful to the consumer with CD who requires a strict gluten-free diet. Therefore, the determination of gluten in all grain-based products, including those made with inherently gluten-free grains or ingredients, is recommended. This study shows that there is no guarantee that products labeled gluten free are in fact gluten free, which could be harmful for patients with CD."

What should practitioners and patients do?

Avoiding gluten is necessary in cases of celiac disease or non-celiac gluten sensitivity but is not recommended in the absence of objective evidence of intolerance. The clinical manifestations of both can be widely diverse and a high degree of suspicion is warranted, not only with chronic unexplained gastrointestinal complaints but also a wide range of disorders with an autoimmune component. A comprehensive Wheat/Gluten Proteome Reactivity & Autoimmunity™ panel is necessary to avoid false negatives.When indicated diligence in remaining gluten free is warranted, but it is unrealistic to expect that inadvertent exposure will never occur. Overall case management mandates a treatment plan that includes support for immune tolerance and regulation of inflammation. Additionally, supplementation during times of heightened risk (such as eating meals outside the home) with enzymes that break down gliadin and wholesome natural anti-inflammatory agents can significantly ameliorate the effect of inadvertent exposure.