Journalists and others should stop referencing or using the study’s findings in any future reporting.
BMJ Group has withdrawn a study that once suggested drinking small amounts of apple cider vinegar each day could support weight loss in people who are overweight or obese.
The clinical trial, published in March 2024 in the open-access journal BMJ Nutrition, Prevention & Health, was accompanied by a press release and quickly drew widespread international attention. Even months later, its claims continued to be cited in media reports.
The decision to retract the paper came after serious concerns were raised about its quality. Issues included questionable methods of statistical analysis, implausible statistical outcomes, unreliable raw data, insufficient detail in the description of methods, and the absence of prior trial registration (a requirement under BMJ Group’s editorial policy).
Early doubts appeared in critiques of the research, with some published as letters in the journal. BMJ Group’s content integrity team then conducted a review and referred the work to independent statistical experts. Their task was to test whether the results could be replicated and to verify the validity of the data submitted by the authors.
Review Findings
It wasn’t possible for the statisticians to replicate the results and multiple analytical errors were identified. There were also irregularities in the data set, and their report, which is appended to the retraction notice, concluded that the data collected from each participant would require further independent scrutiny.
The authors said that the identified errors were honest mistakes, but they agree with the decision to retract the study.
Dr. Helen Macdonald, Publication Ethics and Content Integrity Editor at BMJ Group, said: “Tempting though it is to alert readers to an ostensibly simple and apparently helpful weight loss aid, at present the results of the study are unreliable, and journalists and others should no longer reference or use the results of this study in any future reporting.”
She added: “This retraction reflects our strategic and proactive approach to investigating concerns raised about the content we publish. We act where necessary in the interests of openness and the importance of correcting the scientific record.
“While we deal with allegations as swiftly as possible, it’s very important that due process is followed. Investigations are often complex. This one involved detailed scrutiny of data and correspondence with researchers, institutions, and other experts, for example. Reaching a sound and fair and final decision can therefore take several months.”
Reflection on Publication Decision
Commenting on the decision to publish the study despite the lack of trial registration, Professor Martin Kohlmeier, editor in chief of BMJ Nutrition Prevention & Health, explained: “In hindsight, this was the wrong decision to make. But the authors come from a scientific environment that is underrepresented in nutritional research and the journal aims to prioritize high quality evidence, which usually comes from clinical trials.
“These are relatively unusual in nutritional research as they can be challenging to undertake because of the numbers of participants and time needed to obtain meaningful results.”
Reference: “Apple cider vinegar for weight management in Lebanese adolescents and young adults with overweight and obesity: a randomised, double-blind, placebo-controlled study” 23 September 2025, BMJ Nutrition Prevention & Health.
DOI: 10.1136/bmjnph-2023-000823ret
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