What the New FAO/WHO Gluten Reference Dose Means for People with Celiac Disease
In a global effort to make labeling for gluten less confusing, last month the Food and Agriculture Organization (FAO) and World Health Organization (WHO) released new scientific recommendations to help countries determine when a food should carry a precautionary allergen label such as “may contain gluten.”
This work moved forward quickly over the past year. In July 2024, the Celiac Disease Foundation was asked by our colleagues at AOECS (Association of European Coeliac Societies) and Coeliac UK to engage with the Codex Committee on Food Labelling (CCFL) after Codex raised the possibility of removing celiac disease and gluten from its precautionary allergen labeling framework, since gluten is not an IgE-mediated allergen. In consultation with our scientific experts, the Foundation confirmed that new evidence supported the development of a celiac-specific reference dose (RfD) for gluten—information Codex needed in order to keep gluten within a global risk-based framework. The Foundation then encouraged the International Society for the Study of Celiac Disease (ISSCD) to establish a Gluten Safety Standards Committee, on which we serve, and joined discussions with FAO leadership, including at the Tampere Celiac Disease Symposium. These rapid collaborations helped support Codex’s request to FAO/WHO for scientific advice, leading to the expert consultation convened in Rome in November 2025.
The meeting brought together many of the world’s leading experts in gluten science, celiac disease, food allergy, and analytical testing. Participants included academic researchers, clinicians, laboratory scientists, and regulatory specialists such as Dr. Jason Tye-Din (Australia), Dr. Melanie Downs (United States), and well-known celiac disease and gluten protein experts including Dr. Carolina Ciacci (Italy), Dr. Knut Lundin (Norway), Dr. Katharina Scherf (Germany), and Jennifer Sealey Voyksner (United States) representing the International Society for the Study of Celiac Disease. Additional specialists contributed expertise across food safety, allergen risk assessment, immunology, and analytical detection, ensuring the recommendations were grounded in both clinical evidence and real-world food system considerations.
Importantly, these recommendations do not change the gluten-free diet or alter the long-standing definition of gluten-free. Instead, they update the science used to assess the risk of accidental gluten in foods that are not labeled gluten-free.
In the newly published summary statement, the experts reaffirmed that the global gluten-free standard of no more than 20 parts per million of gluten in foods labeled gluten-free remains appropriate and protective for individuals with celiac disease. What has changed is that, for the first time, FAO/WHO developed a reference dose (RfD) specifically for celiac disease. Previously, there was no celiac-focused threshold to guide when accidental gluten was high enough to justify a “may contain” statement. Some countries relied on thresholds designed for wheat allergy (based on acute IgE reactions) rather than on the long-term intestinal injury relevant to celiac disease. The new recommendations address this gap.
One of the most meaningful impacts of this new guidance is that it helps fix the confusing overlap that currently exists between “gluten-free” and “may contain” labels. Today, it is possible for a food to meet the gluten-free standard of less than 20 ppm yet still carry a “may contain wheat or gluten” warning if the manufacturer cannot fully rule out cross-contact. This conflicts with the intent of gluten-free labeling and causes understandable uncertainty for consumers. The FAO/WHO experts recommended steps to prevent this contradiction.
The experts concluded that a RfD of 4 mg of gluten per eating occasion should be used to determine whether a precautionary allergen label is needed. The RfD serves as a scientific cutoff for regulators: if accidental gluten in a single serving of a food could exceed 4 mg, then a precautionary label should be required. If the amount is below 4 mg, a precautionary label is not necessary. This does not mean that people with celiac disease can safely eat 4 mg of gluten. Additionally, 4 mg of gluten is not a recommended intake level.
Under the updated approach, if a food meets the less than 20ppm gluten-free standard and its potential cross-contact does not exceed the 4 mg reference dose, it should not carry a precautionary allergen label. If accidental gluten could exceed 4 mg per serving, a “may contain gluten” label should be used, and the product should not also carry a gluten-free claim. This will help ensure that “gluten-free” always means gluten-free, that “may contain” signals a true, evidence-based risk, and that these two messages never appear together in ways that confuse consumers.
If countries adopt these recommendations, people with celiac disease may see fewer unnecessary “may contain” warnings, greater access to safe mainstream foods, and improved confidence that labels truly reflect risk. This will also help clinicians give clearer guidance on how to interpret labels and counsel families, especially those experiencing food insecurity or relying on affordable, widely available products. Because Codex processes move slowly and individual countries must revise their own regulations afterward, it will likely be several years before these recommendations lead to any actual changes on food labels.
Most importantly, nothing about the gluten-free diet itself has changed. The less than 20 ppm gluten-free standard stands, avoidance of gluten remains essential, and the health impacts of unintentional exposure remain the same. The new 4 mg reference dose is simply a scientific tool designed to make food labeling smarter, clearer, and more aligned with the realities of living with celiac disease.
Although the United States does not currently participate in precautionary allergen labeling (PAL), the Foundation continues to work globally and here in the U.S. to advance science-based labeling practices and eliminate unnecessary or inaccurate “may contain gluten” statements. By collaborating with U.S. partners, international experts, and regulatory bodies, we are committed to ensuring that labeling reflects real risk and supports safer, more confident food choices for everyone living with celiac disease.