The prevalence of gallstones varies between < 1% and 64% in different populations and is thought to be increasing in response to changes in nutritional intake and increasing obesity. Some people with gallstones have no symptoms but approximately 2 to 4% develop them each year, predominantly including severe abdominal pain, and those who experience symptoms have a greater chance of developing future complications. The main treatment for symptomatic gallstones is cholecystectomy. Traditionally, a low-fat diet has also been advised to manage gallstone symptoms, but there is uncertainty over the evidence to support this.
To evaluate the benefits and harms of modified dietary fat intake in the treatment of gallstone disease in people of any age.
Search methods
We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials in the Cochrane Library, MEDLINE ALL Ovid, Embase Ovid, LILACS (Latin American and Caribbean Health Science Information database; VHL Regional Portal), Science Citation Index Expanded (Web of Science), Conference Proceedings Citation Index - Science (Web of Science), and we also searched online trial registries and pharmaceutical company sources, for ongoing or unpublished trials until 17 February 2023 to identify randomised clinical trials in people with gallstones.
Selection criteria
We included only randomised clinical trials (irrespective of language, blinding, or status) in people with gallstones diagnosed using ultrasonography or conclusive imaging methods. We excluded participants diagnosed with another condition that may compromise dietary fat tolerance. We excluded trials in which data from participants with gallstones were not reported separately from data from participants who did not have gallstones. We excluded trials that did not report the systematic review's predefined outcomes. Trials which investigated other interventions, e.g. pharmaceutical trials, were included if those receiving the other cointervention included both modified dietary fat and control group individuals.
Data collection and analysis
We intended to undertake meta-analysis and present the findings according to Cochrane recommendations. However, as we could identify only one trial, with data unsuitable and insufficient for analyses, we described the data narratively.
Main results
We included one randomised clinical trial (69 participants) in the review, published in 1986. The trial had four intervention groups, but only three of these were of relevance to this review. We assessed the trial at a high risk of bias. The dietary fat modifications included a modified cholesterol intake and medium-chain triglyceride supplementation. The reference (control) treatment was a standard diet. The trial did not report on any of the primary outcomes in this review, i.e. all-cause mortality, serious adverse events, and health-related quality of life. The included trial reported on gallstone dissolution, one of the secondary outcomes of interest in this review. We were unable to apply the GRADE approach to determine certainty of evidence because the included trial did not provide data that could be used to generate an estimate of the effect on this or any other outcome. The trial expressed its finding as "no significant effect of a low cholesterol diet in the presence of ursodeoxycholic acid on gallstone dissolution". No serious adverse events were reported. The included trial reported that they received no funding that could bias the trial results through conflicts of interest. We found no ongoing trials.
Authors' conclusions
The evidence about the effects of modifying dietary fat on gallstone disease versus standard diet is scanty. We lack results from high-quality randomised clinical trials which investigate the effects of modification of dietary fat and other nutrient intakes with adequate follow-up. There is a need for well-designed trials that should include important clinical outcomes such as quality of life, impact on dissolution of gallstones, hospital admissions, surgical intervention, and adverse events.
Original languageEnglish
Publication statusSubmitted - 3 Nov 2023


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