An international cancer research body has written to a leading medical journal outlining concerns about data used to determine the health risks associated with eating red meat.

In a letter to The Lancet, World Cancer Research Fund (WCRF) International echoes calls made by a group of scientists for clarity on the modelling used for the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019.

The study, which was also published in the medical journal, linked a high red-meat diet to 896,000 deaths and 23.9 million disability adjusted life-years.

In February, scientists, including Prof. Alice Stanton and Prof. Patrick Wall from Ireland, called on the authors of the GBD 2019 report to make the evidence they used for the findings available.

They said that all new or updated reviews and meta-analyses on dietary risk factors should be published and subjected to “comprehensive independent peer review”.

WCRF outlined that it supports the call for further clarification, justification, or reconsideration of the study.

“Not only does the increase in the estimated burden appear implausible, but the lack of transparency in the assumptions underlying the calculations undermines the authority of the GBD estimates,” WCRF wrote.

“When the assumptions used within a study are not clearly stated and explained, the results become questionable, and replication difficult,” it added.

WCRF, which has been examining the link between diet, nutrition, physical activity and cancer for 20 years, previously concluded that red and processed meat are causal contributors to the development of colorectal cancer.

“Nevertheless, neither WCRF nor other international organisations recommend complete avoidance of meat,” it noted.

The group outlined that red meat is an important source of several nutrients in many diets worldwide.

“Removing meat from such diets is impractical and unrealistic, and carries a risk of nutritional deficiency judged to outweigh future cancer risk.

“The absence of an explicit rationale for the assumptions underlying the GBD estimates is troublesome, unsupported by the evidence, and unrealistic,” WCRF added.

Since its publication, the GBD data has been cited in 635 documents, 351 scientific papers and nine policy documents.