In a letter published in The Lancet, six leading academics have raised concerns about the dramatic differences in estimated disease burden attributed to unprocessed red meat, cited in the influential Global Burden of Diseases Injuries and Risk Factors (GBD) study 2019, which is led by the Institute for Health Metrics and Evaluation, University of Washington, USA – when compared to the previous GBD in 2017.
The international team of experts, including Professor Chris Elliott of the Institute for Global Food Security (IGFS) at Queen’s University of Belfast, has called on the GBD to publish its evidence behind the 2019 report that has linked consumption of unprocessed red meat to certain diseases.
The letter seeks to emphasise the importance of making research data publicly available so that guidelines and policies can be developed, based on a full understanding of the evidence.
The letter states: “The 2019 estimates of deaths attributable to unprocessed red-meat intake has increased 36-fold and estimates of disability-adjusted life years* attributable to unprocessed red meat intake have increased 18-fold.”
Based on these findings, the GBD 2019 reported that red-meat intake contributes to the causation of a range of diseases including heart disease, breast cancer and stroke, in addition to diabetes and colon cancer.
It appears that the marked increase in the 2019 estimates is dependent on two assumptions – that the optimal intake of red meat is zero, and risks rise sharply even with moderate consumption of red meat.
The authors of the letter were:
Prof. Stanton said: “It is of considerable concern that the GBD 2019 study provides little or no evidence regarding the scientific basis for the assumption that moderate consumption of red meat results in sharp increases in risk of cancers, heart attacks and strokes. Given the substantial influence of GBD reports on worldwide, nutritional-policy decision making, it is of considerable importance that the GBD estimates are subject to critical scrutiny, and that they continue to be rigorously and transparently evidence-based.
“If the current public-health message advising moderate consumption of red meat as part of a healthy balanced diet is replaced by the message that any intake of red meat is harmful, then childhood malnutrition, iron-deficiency anaemia in women of child-bearing age and elderly fragility will greatly increase.”
Prof. Elliott of Queen’s said: “It is of huge importance that the evidence supporting the negative health impacts around red-meat consumption is made available. It is hard to understand how such conclusions could have been published without a strong evidence base that can be subjected to scientific scrutiny.”
The letter further suggests that the GBD 2019 dietary-risk estimates are not used in any national, or international, policy documents until comprehensive independent peer reviews have been conducted of the evidence underpinning the revised estimates.
* DALYs are an internationally recognised measure of the impact of diseases on populations.