Soluble and Osmotic Fibre (SOLOS) Diet for Constipation

Aims: This retrospective clinical audit study aims to evaluate the effectiveness of dietary advice promoting increased intake of soluble fibre and poorly absorbed (osmotic) carbohydrates, with or without restriction of fructans and galacto-oligosaccharides (GOS), on adult patients (18-70 years old) with functional bowel disorders with constipation from the UK by comparing to baseline scores for severity and frequency of gastrointestinal symptoms and stool output.

Hypothesis: The dietary advice promoting increased intake of soluble fibre and osmotic sugars will produce a significant change from baseline in gastrointestinal symptoms and stool output in adult patients (18-70 years old) with functional bowel disorders with constipation from the UK.

Methodology: The study population will include all patients who have consulted with the Principal Investigator, a specialist gastroenterology dietitian between January 2021 and December 2025. All patients who have met the inclusion criteria will then form the research sample. Eligible subjects' data and study variables will be extracted from patient letters and clinical management records without direct patient contact. These study variables include the frequency and severity of the patients' symptoms at their initial appointment and follow-up appointment if available. Anthropometric data such as height and weight will also be obtained. The compiled data will then be analysed by conducting statistical tests, specifically the paired t-test, which will produce descriptive statistics that will interpret the effectiveness of the SOLOS diet on patients with functional bowel disorders with constipation.

Applications: To date, there has not been any study studying the dual effects of soluble fibre and osmotic carbohydrates consumption on alleviating constipation-related symptoms in patients with functional bowel disorders with constipation. Therefore, this research aims to present novel findings that can advance existing dietary management of functional bowel disorders with constipation. These results are expected to deepen understanding and research in food manufacturing and clinical nutrition.

Inclusion criteria

• Presented with symptoms of FC, IBS-C, or SIBO-C
• Were aged 18 to 70 years old. (Research focus is on adult patients, excluding older adults and children)
• Date of baseline (first) and follow-up appointments ranged from January 2021 to December 2025
• Did not attend follow-up appointments (Data would be treated as "intention to treat" and data points were carried forward for conservative analysis).

Exclusion criteria

• Had no history of constipation-related symptoms (Does not relate to research question's population or outcome)
• Started treatment before January 2021
• Were not due for follow-up before the end of December 2025
• Symptom and stool data inadequately recorded