Is “Gluten-Free” Beer Made From Barley Malt Safe for Celiacs?
By: Peter Olins, PhD on October 22, 2012
Making gluten-free beer is a challenge: almost all traditional beers are based on barley malt, which is responsible for their distinctive flavor. Unfortunately, barley also contains hordein—a protein related to wheat gluten—so traditional beers and malt-based foods are unacceptable for people on a gluten-free diet. With the increasing recognition of celiac disease in the population, and the increasing popularity of gluten-free foods, there has been a major effort among brewers to find alternatives to the traditional barley-based beer process.
Currently, there are two approaches for producing gluten-free beer:
- Use grains or seeds that are naturally gluten-free
- Start with barley malt, but then remove the gluten at a later stage
When low-gluten beer is based on barley, enzymes are used to break down the hordein into small “peptide” fragments. This is a complex mixture which is hard to measure accurately, and there is no test which has been approved for routine screening. More importantly, these small peptides have not been tested to see whether they are still toxic to celiacs.
This article will focus on the challenges in using barley malt to produce a gluten-free beer.
Gluten-Free Beers Made Without Barley or Wheat
Many breweries now produce gluten-free beer in which the barley has been substituted with other grains or seeds that are naturally gluten-free. Sorghum is commonly used as an alternative to barley, but some breweries have been experimenting with a variety of other seeds, such as rice, quinoa, millet, or buckwheat. Depending on your individual taste preferences, these beers may or may not be an acceptable substitute for barley-based beer. They may also be more expensive due to changes in the brewing process and the cost of ingredients.
Destroying “Gluten” in Barley-Based Beer Using Protein-Digesting Enzymes
Wheat gluten is a mixture of literally hundreds of closely related proteins; the equivalent protein in barley is called hordein. The alternative approach for creating a safer beer is to start with barley malt, but then adjust the process so that the hordein is broken down, and the gluten-like peptide fragments are inactivated. The idea is to remove all the peptide fragments that are responsible for provoking an immune response in celiacs. This is the approach that has been taken by such companies as Widmer Brewing and Two Brothers Brewing. The barley malting process already breaks down the majority of hordein; then, a commercially-available enzyme preparation called Clarex breaks down these peptides even further (Ref. 1).
The advantage of this approach is that many of the flavor and sensory properties of barley malt can be preserved. However, there are two downsides to this approach. Additional processing steps can add to the cost of production, and more importantly, it is hard to measure how much residual “gluten” is left. At the moment, beers based on barley malt cannot be labeled as “gluten-free” in the US (see below).
Regulation of Gluten-Free Foods by the Food and Drug Administration (FDA)
The FDA is currently working to define what products can be labeled “gluten-free” in the US. The wording of these regulations has not been set, but a draft regulation has been published. The draft makes it clear that barley-based foods cannot be labeled as gluten-free, unless the gluten has been removed to a level less than 20 ppm. Unfortunately, the FDA acknowledges that there is currently no available assay to determine the level of gluten in “hydrolyzed foods” in which the gluten has been broken down (such as beer made from barley). The FDA hopes to finalize its regulations by the end of the year.
Regulation of Gluten-Free Beer by the Tobacco Tax and Trade Bureau (TTB)
The TTB is responsible for regulating the labeling of alcoholic drinks in the US. The organization attempts to stay in step with the FDA, but since there is no final FDA definition of gluten-free foods, the TTB issued an interim policy on May 24, 2012 (Ref. 2). For now, beers claiming to be “Gluten-Free” can only be made from ingredients that are naturally gluten-free, such as sorghum. Beers based on barley—even if the majority of the gluten (hordein) has been removed—must adopt the following two rules, quote:
(1) One of the following qualifying statements must also appear legibly and conspicuously on the label or in the advertisement as part of the above statement: “Product fermented from grains containing gluten and to remove gluten. The gluten content of this product cannot be verified, and this product may contain gluten.”
OR,“This product was distilled from grains containing gluten, which removed some or all of the gluten. The gluten content of this product cannot be verified, and this product may contain gluten.”
(2) TTB will not approve labels containing the above claims unless the label application contains a detailed description of the method used to remove gluten from the product and R5 Mendez Competitive ELISA assay results for the finished product showing a response of less than 20 ppm gluten (and the name and manufacturer of the assay). Industry members should also be prepared to substantiate advertising claims with the same information, upon request.
The TTB also states that, quote:
Because the current tests used to measure the gluten content of fermented products have not been scientifically validated, such statements may not include any reference to the level of gluten in the product. TTB believes that the qualifying statement is necessary to avoid misleading consumers about the gluten content of these products because of the serious health consequences associated with the consumption of gluten by individuals with celiac disease.
FDA Proposes 20 ppm Limit for Gluten-Free Foods
Almost everyone in the celiac community is aware of the proposed FDA standard for “gluten-free” food labeling—foods must contain less than 20 ppm gluten. This standard is based on very limited clinical studies measuring the safety of the intact protein. As described in our article last year, there are significant challenges in devising a meaningful standard for ensuring that gluten-free foods are safe for celiacs (Ref. 3). These assays provide an estimate of the total amount of gluten in a food, but they are not a direct measure of food safety, and may not be adequate for the needs of all celiacs.
Currently, there are excellent assays available for measuring the level of intact gluten (or related proteins) in foods. The “R5 Mendez Sandwich ELISA” is the preferred assay selected by the FDA in its draft regulations. These assays are an attempt to provide standards that will ensure safety for the majority of celiacs. The assay is based on an antibody, called R5, that recognizes a specific short sequence of 5 amino acids. Since this sequence is present in many of the components on gluten, it provides a convenient way to estimate the amount of gluten present. Related proteins from barley or rye are fairly similar in structure to wheat gluten; the antibody cross-reacts with these proteins, and can be used to estimate the amount of “gluten” in these grains.
The Challenge of Measuring Gluten in Fermented Foods: What Does “20 ppm” Gluten Really Mean?
There are problems with assaying for “gluten” in beer. Hordein is partially broken down in the brewing process into smaller protein fragments (peptides), but these peptides do not react properly in the Sandwich ELISA. At the moment, there is no FDA-approved assay for “hydrolyzed” gluten (or hordein). The one assay that is commercially available (R5 Mendez Competitive ELISA) measures peptide fragments of gluten (Ref. 4). The competitive ELISA doesn’t measure gluten directly; instead, it uses an artificial mixture of peptides prepared by treating protein from wheat, barley and rye with human digestive enzymes. This seems promising, but it is currently impossible to make a direct comparison with the assay used for intact gluten.
Even less is known about the safety of gluten-related peptide fragments, so “20 ppm” gluten-like peptides doesn’t mean the same as 20 ppm intact gluten. Obviously, consumers are less interested in a specific number, and more concerned about safety. I am not aware of any studies that have addressed this question so far. I am concerned that the general public will misinterpret a value of less than 20 ppm “gluten” in the Competitive ELISA, and will assume that this corresponds to a comparable level of safety as the original 20 ppm value derived using the Sandwich ELISA.
Three Concerns About the Use of the R5 Mendez Competitive ELISA Assay for Gluten-Free Beer:
1) The R5 antibody does not detect all the peptides that are potentially toxic.
2) The peptides used to calibrate the assay are quite different from the ones created during beer-making.
3) The assay does not actually measure whether the remaining peptides in beer can still provoke an immune reaction in celiacs.
In other words, while an assay such as the Competitive ELISA may be able to give consistent values for a given sample of beer, there is no way to extrapolate to an estimate of safety.
The FDA has stated that it hopes to issue final regulations for gluten-free labeling by the end of 2012. Personally, I doubt whether there will be enough time to include a meaningful gluten standard for hydrolyzed proteins (such as the peptides in beer).
What about Personal Anecdotes that Gluten-Reduced Beers do not Cause Symptoms?
This is certainly encouraging, but it seems unwise to extrapolate from a few personal experiences. In addition, subjective symptoms are a poor test for the safety of a gluten-containing food: in one study, patients consuming low levels of gluten lacked any obvious symptoms, but still had significant intestinal damage (Refs. 5,6).
Other Approaches to Detoxifying Gluten
It’s interesting to note that the idea of inactivating gluten by breaking it down into small fragments is actually a very promising approach. Alvine Pharmaceuticals is developing an enzyme-based drug that would be given orally to remove traces of dietary gluten. Early clinical studies have indicated that the drug, ALV003, can reduce celiac symptoms. Nevertheless, a lot more work needs to be done in order to ensure that this enzyme is both safe and efficacious (Ref. 7).
So, Is Barley-Malt Beer Crafted to Remove Gluten Safe for Celiacs?
- As an alternative to gluten-free beers based on sorghum, reduced gluten beers which rely on breaking down the hordein in barley malt are promising, but their safety for people with celiac disease is unproven.
- There is no available assay that has been approved for the measurement of hydrolyzed gluten.
- We look forward to the development of reliable assays so that in the future, barley can be used to prepare gluten-free beer.