The growing demand for gluten-free products has prompted the brewing industry to develop new varieties made from barley that has undergone gluten removal processes. However, the absence of gluten as such does not imply the absence of other compounds capable of causing digestive upset in sensitive individuals. This is borne out by a study analysing 60 samples of Spanish beers, both with and without gluten, by the EHU's GLUTEN3S research group, and funded by the Spanish Ministry of Science, Innovation and Universities, the Basque Government and the EHU.

Fructans and ATIs: natural compounds that also matter

The work focused on two types of molecules found in cereals: fructans and amylase/trypsin inhibitor (ATI) proteins. Fructans are complex carbohydrates that act as an energy reserve in numerous plants, such as garlic, onions, barley, wheat, and bananas. Although they have beneficial prebiotic effects, they can cause bloating, gases, or abdominal pain in sensitive individuals.

Fructans belong to the FODMAP group; they are short-chain carbohydrates present in everyday foods and which can cause gastrointestinal symptoms in people with digestive sensitivity, such as those who suffer from Irritable Bowel Syndrome (IBS). Temporarily restricting these foods may help to reduce these symptoms.

ATIs are proteins that protect plants against pests and insects, but which can activate the innate immune system in the human body. Various studies regard them as a significant trigger in non-coeliac gluten sensitivity, associated with digestive discomfort and, in some cases, inflammatory processes.

The results show that there are no significant differences between beers with and without gluten in terms of fructan and ATI content. Although gluten-free beers comply with the regulations and are safe for people with coeliac disease, the presence of these compounds could explain why some people continue to experience discomfort even when they opt for gluten-free products. “We have opened up a new avenue to explain the symptoms experienced by people who consume gluten-free beer, an alternative to research focusing on the immunogenic peptides that may be present in this beverage,” said Jonatan Miranda, author of the article and member of the GLUTEN3S research group.

Differences between batches and a proposal for more informative labelling

The analysis also showed that the amount of fructans and ATIs may vary depending on factors such as the original dry extract, alcohol content, or differences between production batches. These variations highlight the need for more specific controls, comparable to those already in place for gluten detection.

Taking these results as the basis, the GLUTEN3S research group proposes moving towards complementary labelling that allows beers low in fructans to be identified, thus facilitating a more informed choice for those who suffer from digestive sensitivity or FODMAP intolerance. “Other countries are already working on this,” said Dr Miranda. In addition to analysing the presence of these compounds, the study also tests and confirms the effectiveness of new analytical methods capable of detecting fructans and ATIs. These tools enable the brewing industry to better control the composition of its products and help research teams drive forward their research into nutrition and digestive health, as they offer more reliable, detailed measurements. “The methods developed seek to facilitate control by the brewing industry, by offering rapid, simple, routine procedures,” concluded Miranda.

This study was funded by the R&D&I project PID2021-125695OA-I00 (MCIN/AEI/10.13039/501100011033), with support from the European Regional Development Fund (ERDF) and the Basque Government within the “From Farm to Table 2022–2026” Plan.