Yilmaz 2019.

Study characteristics
Methods	RCT Setting: unstated (single centre, Turkey) Study period: May 2015 to December 2016
Participants	Inclusion criteria: Patients with IBD participated in the study. CDAI was used for CD, and Truelove‐Witts scoring systems were used for UC for disease assessment scores (10‐11). Patients with CD whose CDAI score was < 450 were admitted to the study. Patients with UC whose Truelove‐Witts score was severe were not admitted to the study. Participants also had to be > 18 years old. Exclusion criteria: Patients with alcohol consumption > 20 g/day, allergies or intolerance to milk, antibiotic treatment within the last 1 month, column or bowel operation history up to 3 months before the start of the study, and the presence of active infection within 1 month prior to the start of the study or during the study were excluded. In addition, if a participant requested to leave on his/her own will, or if kefir was not consumed continuously for 2 weeks, the trial protocol was assessed and was not approved. Age (mean (range)): IG CD: 33 (24 to 65) CG CD: 42 (21 to 66) IG UC: 33 (19 to 68) CG UC: 43.5 (29 to 76) Sex (M/F): IG CD: 4/6 CG CD: 6/4 IG UC: 9/6 CG UC: 4/6 Site of disease: IG CD: colon: 1; ileum: 6; colon + ileum: 3 CG CD: colon: 0; ileum: 10; colon + ileum: 0 IG UC: colon: 15; ileum: 0; colon + ileum: 0 CG UC: colon: 10; ileum: 0; colon + ileum: 0 Use of concurrent medication: NS Disease activity: inactive to moderate Disease duration: IG CD: 2 (1 to 9) years CG CD: 2 (1 to 10) years IG UC: 4 (1 to 12) years CG UC: NS Number randomised: IG: 28 CG: 20 Number reaching end of study: IG CD: 10 CG CD: 10 IG UC: 15 CG UC: 10 Number analysed: IG CD: 10 CG CD: 10 IG UC: 15 CG UC: 10 Postrandomisation exclusion: IG: 3 (did not want to drink kefir); CG: 0
Interventions	IG: 400 mL/day kefir was administered twice a day to participants for 4 weeks, which contains a total of 2.0 × 10¹⁰ colony‐forming units/mL viable Lactobacillus bacteria. CG: no placebo or other intervention
Outcomes	Length of intervention: 4 weeks Primary outcomes: Pain intensity: Participants were asked to fill out the symptoms diary, which included questionnaires about bowel habits. Abdominal pain was rated on a 4‐point scale: 0 = none, 1 = mild, 2 = moderate, 3 = severe. The results were received after contact with the author Secondary outcomes: None reported
Notes	Funding source: The authors declared that this study received no financial support. Conflict of interest: The authors have no conflicts of interest to declare. Author contact details: ilkayilmaz001@hotmail.com
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	We contacted the author, who responded that randomisation was determined via a computer.
Allocation concealment (selection bias)	Unclear risk	Not mentioned. We requested further information from the author but did not receive a response.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not possible for this type of intervention
Blinding of outcome assessment (detection bias) All outcomes	Low risk	We contacted the author, who responded that the outcome assessor was blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Data are presented for all completers.
Selective reporting (reporting bias)	Low risk	All outcomes are reported in the results, and scores were provided to us by the author.
Other bias	Low risk	The authors report no conflicts of interest, and the baseline characteristics appear to be reasonably balanced, although this is not mentioned in the text.

5‐ASA: 5‐aminosalicylic acid

CD: Crohn’s disease

CDAI: Crohn’s Disease Activity Index

CG: control group

CRP: C‐reactive protein

ESR: erythrocyte sedimentation rate

FODMAP: fermentable oligo‐, di‐, monosaccharides and polyols

GSRS: Gastrointestinal Symptom Rating Scale

HADS: Hospital Anxiety and Depression Scale

HBI: Harvey‐Bradshaw index

IBD: inflammatory bowel disease

IBS: irritable bowel syndrome

IBS‐SSS: Irritable Bowel Syndrome Severity Scoring System

IG: intervention group

ITT: intention‐to‐treat

NS: not stated

PP: per protocol

RCT: randomised controlled trial

SCCAI: Simple Clinical Colitis Activity Index

SD: standard deviation

SEM: standard error of the mean

SS: sum of squares

UC: ulcerative colitis

VAS: visual analogue scale