Coeliac Disease (CD) is a lifelong autoimmune condition where eating gluten (a protein found in wheat, barley, and rye) causes damage to the small intestine. It affects around 1 in 100 people. Most individuals feel better and their gut heals after switching to a strict gluten-free diet. However, up to 1 in 5 people with coeliac disease continue to experience unpleasant gut symptoms-such as bloating, pain, and diarrhoea-despite following the diet and having a healed intestine. These ongoing symptoms can be very distressing and impact daily life.

This study investigates whether a food supplement called Symprove, a probiotic drink containing live good bacteria, can help relieve these ongoing symptoms. Scientists believe that in some people with coeliac disease, the community of bacteria in the gut (called the microbiota) becomes unbalanced, even after going gluten-free. This imbalance (known as dysbiosis) may lead to inflammation, irritation, and symptoms similar to irritable bowel syndrome (IBS).

The aim of this study is to test whether Symprove can help correct this imbalance and reduce symptoms. Participants will take Symprove daily and their symptoms, quality of life, and gut bacteria (measured from stool samples) will be monitored over time.

The study hopes to answer three key questions: Can Symprove reduce gut symptoms in people with coeliac disease who are in remission? Does it work by restoring a healthy balance of gut bacteria? Are people with more severe imbalance (dysbiosis) more likely to have symptoms?

If successful, this research could offer a safe, non-drug option to improve life for coeliac patients who continue to suffer symptoms despite avoiding gluten. It could also help suggest that gut bacteria play a role in ongoing symptoms and are a target for future treatment.

Inclusion Criteria:

Adults aged 18-65 years with biopsy-confirmed coeliac disease (CD)

Normal duodenal biopsy (Marsh 0 or Marsh I) within the last 12 months, confirming histological remission

Adherence to a strict gluten-free diet (GFD) for at least 6 months

Persistent gastrointestinal (GI) symptoms for at least 6 months despite adherence to GFD and histological remission

Ability to provide written informed consent

Exclusion Criteria:

Active gluten ingestion or non-adherence to a gluten-free diet

Use of antibiotics within the past 3 months

Use of probiotics within the past 3 months

Known comorbidities affecting gastrointestinal function (e.g., Crohn's disease, ulcerative colitis, irritable bowel syndrome with severe diarrhea, or other significant gastrointestinal disorders)

Pregnancy or lactation

Inability to provide informed consent

De-identified individual participant data (IPD) that underlie published results will be made available to researchers upon reasonable request following completion of the trial and publication of the main findings. Data will be stored securely and released only with appropriate approvals, in accordance with the Data Protection Act 2018 and Sheffield Teaching Hospitals NHS Trust policies. Requests for access may come from both internal and external research collaborators, and all IPD will be stripped of direct patient identifiers prior to sharing.

Once main finding and results have been published

Applications for access will be assessed by the CI and investigator team.