Gluten-intolerant people who are aware of their condition know what they need to avoid eating in order to prevent serious health consequences.
It's easy enough to find celiac-safe products like gluten-free beer these days, but a new study shows that the most common method of assessing gluten levels in beer is inaccurate.
Gluten, a flexible protein found in common grains like wheat, barley and rye, is present in an enormous variety of commonly consumed American foods like bread, pasta, and beer.
An increasing number of people are being diagnosed with gluten sensitivity, a spectrum of immune conditions from mild gluten allergy to celiac disease that can cause digestive issues or joint pain if gluten is eaten regularly. For celiacs, it can eventually lead to intestinal damage and severe nutrient deficiencies.
Promising research may eventually allow the gluten-intolerant to eat wheat products without harmful reactions, but for the time being the only way to manage gluten intolerance is to stick to a strict gluten-free diet.
New research, however, might complicate that effort for beer-loving celiacs.
Australian scientists from the Commonwealth Scientific and Industrial Research Organisation in Canberra conducted a study published in the journal PLOS One on February 28, finding that a widely used method of detecting gluten levels in beer is often inaccurate.
Most beers are brewed with gluten-rich malted wheat or barley, but it's possible to extract the gluten after brewing. That process removes enough of the protein to be considered gluten-free according to current international standards, but highly sensitive drinkers often still avoid them.
The researchers examined 60 common beers to see whether their levels of hordein, a common barley-derived type of gluten protein, were accurately detected by enzyme-linked immunosorbent assay (ELISA), the test approved by the World Health Organization to detect gluten.
ELISA is relatively simple to perform, but the scientists found that it often failed to accurately detect high hordein levels compared to a more sensitive but complicated method, multiple-reaction monitoring mass spectrometry (MRM-MS).
Whereas ELISA uses antibodies to detect substances, mass spectometry detects the contents of samples by ionizing them, then sorting them by particles' mass and charge.
The methods used in the study measured hordein levels on a scale from zero for completely gluten-free beers, to 47,000 parts per million (ppm) for wheat-based beers.
The findings showed that two of the beverages marketed as gluten-free beer and two of the low-gluten beers had ELISA readings of zero, but were actually revealed by mass spectometry to have significant, or near average, levels of hordein. Six beers gave false negatives, with zero ELISA readings but average hordein content by MRM-MS.
Overall, 10 of the 60 commercial beers were assessed by ELISA as having hordein levels of less than 1 ppm, whereas mass spectometry results showed that they actually had near average hordein content.
Half of the commercial gluten-free beers were free of hordein according to both methods.
The study showed that ELISA fails to accurately measure hordein proteins that are altered during the beer-brewing process, but can still cause health problems for gluten-intolerants. Most barley-derived beers contain only trace levels of hordein, but those levels are still too high for celiacs and gluten-intolerants to drink safely.
The researchers concluded that ELISA, while convenient, is no longer a suitable method of measuring gluten in beverages derived from wheat or barley.
The team is working on a simple, rapid, and more accurate method of measuring gluten based on mass spectrometry, which the food industry and regulatory boards can eventually use to protect celiacs by accurately labeling foods and beverages as "gluten-free."
Until then, gluten-intolerant beer lovers can take comfort in beers that are certain to be gluten-free.
NPR suggests a wide variety of gluten-free beers brewed with alternative free grains like sorghum, rice, buckwheat, or millet, which can be as delicious as beers derived from wheat and barley even for non-celiacs.
"You won't know what you're missing," said Josh Bernstein of Bon Appetit after trying a few.