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NCT Number: NCT07052890

Curcumin, Vitamin D and Green Tea in IBS-D

Irritable Bowel Syndrome (IBS) is a highly prevalent condition of the gastrointestinal tract that has significant impact on sufferer's quality of life. The diarrhoea variant (IBS-D) makes up around one third of all IBS sufferers. There is currently a lack of both effective pharmacological and non-pharmacological treatments for IBS-D.

Three food supplements: Green tea, vitamin D and curcumin have all been shown to demonstrate benefit in either reducing symptoms in IBS or diarrhoea as individual ingredients, but have never been tested in combination to assess their effectiveness in IBS. This research study aims to examine the effectiveness of green tea, vitamin D and curcumin in combination compared to a placebo capsule in individual suffering from IBS-D.

The study will aim to enroll 78 participants with IBS-D and utilise a placebo-controlled double blind design. The study will consist of a 2 week screening period, a 4 week randomised treatment period (50% participants to receive placebo, 50% to receive active treatment), followed by a 4 week open label treatment period (all participants to receive the active study product).

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Key information

Conditions

Irritable Bowel Syndrome (IBS) Colonic Diseases Colonic Diseases, Functional Digestive System Diseases Gastrointestinal Diseases Intestinal Diseases Irritable Bowel Syndrome Irritable Bowel Syndrome With Diarrhea (IBS-D)

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

The Functional Gut Clinic Cambridge, Cambridge, United Kingdom

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Participant has provided written informed consent before participating in the study after being given a full description of the study and prior to any study-specific procedures being performed.
  • Participant has irritable bowel syndrome with diarrhoea (IBS-D), as defined by the Rome IV criteria.
  • Participant has an IBS-SSS score of >175 at screening.
  • Participant is a male or non-pregnant female and is ≥18 years of age
  • Participant can communicate well with the Investigator and to comply with the requirements for the entire study.
  • Participant has capacity to understand written English.
  • Participant has a body mass index (BMI) of 18.5 - 39.9kg/m2 (bounds included).
  • Participant agrees to follow all pre-test preparation before breath testing visits.

Exclusion criteria

  • Prior abdominal surgery other than appendectomy and cholecystectomy.
  • Known hypercalcaemia.
  • Participating in another trial or taken an IMP within the last 1 month.
  • Females who report to be pregnant or lactating
  • Unwilling to maintain stable doses of permitted concomitant medication
  • Unwilling to maintain a stable diet for the duration of the trial
  • Being in the opinion of the investigator unsuitable
  • Insufficient knowledge of English to complete the daily bowel diary and food diary
  • Hypersensitivity to any component of the supplement
  • Hypersensitivity or known allergy to lactulose
  • Drug interactions with any component of the supplement
  • Consumption of antibiotics, prebiotics or probiotics (in food products or as supplements) in the last 4 weeks prior to, or during the study.
  • Vitamin D two week washout
  • Participants who have received bowel preparation for investigative procedures in the 4 weeks prior to the study
  • Individuals declaring additional specific dietary needs
  • Inflammatory bowel disease or coeliac disease
  • Any other condition, deemed by the investigator, that may be causing their symptoms
  • No major co-morbidity.
  • Participant is involved in this study as an Investigator, sub-Investigator, study coordinator, other study staff, or Sponsor member.

Treatment and study plan

Curcumin, vitamin d and green tea extract

Dietary Supplement

A combination of the following ingrediants per 4 capsules:

CurcuWin® 1000mg - of which 200mg Curcuminoids

Green Tea Extract 400mg - (0.1-0.5% caffeine)

Vitamin D₃ 50 µg 2000IU

Placebo Capsule(s)

Dietary Supplement

Placebo - identical capsules containing inert color matched power

Primary outcomes

  1. Mean decrease of Irritable bowel syndrome symptom severity score (IBS-SSS)

    Time frame: From Enrollment to end of 4 week randomised treatment period

    Mean change in IBS-SSS at the end of the randomised treatment phase between Active and placebo arms.

    The IBS-SSS is numeric score based on 5 questions (each rated 0-100), with a total minimum score of 0 and maximum of 500, with a higher score indicating greater severity of symptoms.

Secondary outcomes

  1. Use of rescue medication

    Time frame: 4 weeks

    Average change in rescue medication use from week 1 of randomisation period compared to week 4 of randomisation period, between active and placebo arms

  2. Assessment of change breath methane levels during hydrogen and methane breath testing (HMBT)

    Time frame: 4 weeks

    Assessment of effect of active treatment vs placebo on breath hydrogen levels from baseline to end of randomised treatment period.

    Breath hydrogen levels will be measured using a lactulose hydrogen and methane breath test. Total area under the curve for methane during the test will be calculated.

  3. Mean change irritable bowel syndrome quality of life (IBS-QoL) questionnaire score

    Time frame: 4 weeks

    Mean change IBS-QoL scores from baseline to end of randomised treatment period, between active and placebo groups.

    The IBS-QoL questionnaire is made up of 34 questions each scored 1-5. Higher scores indicate better quality of life. Lower scores suggest more severe impact of IBS on daily living.

  4. Longevity of treatment effect

    Time frame: 8 weeks

    Longevity of treatment effect assessed in the active group with comparison of IBS-SSS scores from the randomised treatment period to end of open label period.

    The IBS-SSS is numeric score based on 5 questions (each rated 0-100), with a total minimum score of 0 and maximum of 500, with a higher score indicating greater severity of symptoms.

  5. Stool Consistency

    Time frame: 4 weeks

    Stool Consistency assessed as average number of days with Bristol Stool Scale type (mean over 4 weeks, mean of first week and last week of the randomisation period).

    A favorable change in mean score would be changes from type 6 or 7 stools (diarrhoea type stool consistency) to type 3,4,5 stools, which are considered normal stool consistency.

  6. Stool frequency

    Time frame: 4 weeks

    Stool Frequency (mean of 4 weeks, mean of first week and last week of the randomisation period)

  7. Change in bloating measured using daily bowel diary.

    Time frame: 4 weeks

    Change in average daily bloating score for week 1 of the randomised treatment period to week 4 of the randomised treatment period.

    Severity of bloating will be scored daily by participants on a scale of 0-3, 0 being no bloating, 3 being severe bloating.

  8. Change in abdominal pain measured using the daily bowel diary

    Time frame: 4 weeks

    Change in average daily abdominal pain score for week 1 of the randomised treatment period to week 4 of the randomised treatment period.

    Severity of abdominal pain will be scored daily by participants on a scale of 0-3, 0 being no bloating, 3 being severe bloating.

  9. Breath Hydrogen levels measured using hydrogen and methane breath testing (HMBT)

    Time frame: 4 weeks

    Assessment of effect of active treatment vs placebo on breath hydrogen levels from baseline to end of randomised treatment period.

    Breath hydrogen levels will be measured using a lactulose hydrogen and methane breath test. Total area under the curve for hydrogen during the test will be calculated.

Sponsors and collaborators

Lead sponsor

Dr Anthony Hobson

Other

Registry information

Official study title

Role of a Food Supplement Containing Curcumin, Green Tea and Vitamin D on Symptom Control in Diarrhoea Predominant Irritable Bowel Syndrome (IBS-D)

Important dates

Study start
2024
Primary completion
2025
Study completion
2026
First posted
Jul 8, 2025
Registry last updated
Mar 11, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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