The goal of this clinical trial was to investigate if intestinal deamidation of gliadin from wheat bread could be hindered by adding a E304i/zinc additive. The study was a randomized double-blind 4-week crossover intervention in 20 healthy volunteers in which the participants ingested 2 bread rolls a day during the intervention weeks.

The question it aimed to answer was if there was a difference in blood levels of deamidated gliadin peptides after ingestion of the reference wheat bread compared with the wheat bread containing the food additive.

Inclusion Criteria:

• Signed informed consent
• Body mass index between 18.5 to 32
• Age between 18-50 years
• No tobacco use

Exclusion Criteria:

• Celiac disease and other diagnosed enteropathies
• Gluten-free diet
• Dietary supplementation (minerals (calcium, zinc, vitamin D) and proteolytic enzymes, probiotics)
• Pregnancy or lactation
• Lack of suitability for participation in the study, for any reason, as judged by the medical doctor or the project PI.
• Withdrawn consent: Participant withdraws consent.
• Non-compliance: Participant fails repeatedly to comply with study protocol (diet, study visits and provide samples)

The data and the study protocol will be published in a scientific journal. Participant data are anonymized and cannot be connected to an individual person.

As soon as published, no time limit

The study will be published in an open access journal

The participants did not know which bread was received; the bags were color-coded. The personnel meeting the participants did not know which color belonged to which bread. Only the principal investigator (and the bakery) not meeting participants knew which color belonged to which bread type.