‘I’ve never seen anything like it’: Scientists raise concerns over study claiming red meat and bacon’s link to cancer ‘has no evidence’

‘These authors I think are wrong about absolutely everything,’ doctor says

Vincent Wood
Tuesday 01 October 2019 21:18 BST
The study has faced significant push back from the scientific community
The study has faced significant push back from the scientific community (iStock)

Scientists have raised concerns over a new study which claims there is little to no evidence that cutting out red meat limits the risk of cancer, heart disease or diabetes.

In a paper published in the Annals of Internal Medicine, a panel of 14 experts in research methodology and nutrition from seven countries looked at multiple studies carried out on 54,000 people.

In the assessment, which did not consider the impact on the environment or animal welfare, they said they could not find “statistically significant evidence” that the risk was reduced when red meat or processed meat was removed from diets.

This finding was then combined with research on the public which said that “people who eat meat enjoy it, they think of it as helpful and they’re reluctant to change their dietary habits”, according to author Dr Bradley Johnson.

He added the result was that, “given that there’s low-quality evidence or low certainty evidence, combined with what we know about values and preferences, we made a weak recommendation that, for some people – but not everyone – the right approach is to continue their meat consumption.”

However the study has faced significant push-back from the scientific community, with the Harvard TH Chan School of Public Health’s Department of Nutrition issuing a 2,000-word rebuttal, which said the findings were a misreading of the study’s own data.

The critique also featured comments from scientists whose research was included arguing the finding was a misrepresentation of their work. One researcher from the US Women’s Health Initiative, which Dr Johnson told The Independent was a “primary focus for the process of making our recommendations”, said the study was a “misuse and misinterpretation of data from the WHI”.

Asked to respond to the criticism, Dr Johnson said he disagreed, arguing the way data was assessed in the study – a system more typically used for drug trials – made it “the most evidence-based approach ever in the field of nutrition”.

But Dr David Katz, founder of the Yale-Griffin Prevention Research Centre, told The Independent: “These authors, I think, are wrong about absolutely everything. They’re actually issuing guidelines at odds with their own study. I’ve never really seen anything like it before in my entire career.”

Describing the decision to throw support behind eating meat as “tragic”, he added that the study’s own data showed “significantly and consistently” that there were “higher rates of death, heart disease, cancer and diabetes with higher intakes of red and processed meats”.

Tim Key, professor of epidemiology and deputy director of the cancer epidemiology unit at the University of Oxford, added: “There’s substantial evidence that processed meat can cause bowel cancer – so much so that the World Health Organisation has classified it as carcinogenic since 2015.

“Today’s new publication reports results essentially identical to the existing evidence, but describes the impact very differently, contradicting the general consensus among cancer research experts.”

Concerns were also raised over the assurance that eating red and processed meat did not carry risks being spread to the population at large.

“I’m a physician” Dr Katz added. “If I’m talking to an individual patient and I say, ‘You want to eat meat and you really ought to cut back, but if you don’t it’ll only modify your risk a little bit, and maybe I can manage that with medication,’ that’s one thing.

“But let’s just say we’re talking about shifting a risk of dying up by one per thousand people per year. Well for an individual that’s a small risk. At the level of the US population that’s a variance of 325,000 unnecessary premature deaths per year. There’s nothing small about that.”

The Harvard rebuttal of the study also criticised authors for failing to consider the environmental impact of meat – a choice understood to have been made due to the limited resources of the research group.

Citing a report published by the EAT-Lancet commission, Dr Katz said humanity needed to reduce its meat intake by about 90 per cent to stay within sustainable limits. “We destroy biodiversity, we dry out our aquifiers, we acidify the oceans – we soil our nest. You can’t ignore that when we’re talking about human health. That is the greatest human health event of all,” he said.

The World Cancer Research Fund recommends avoiding processed meat altogether due to its carcinogenic properties, while the Department of Health and Social Care recommends anyone who eats more than 90g of processed red or processed meat per day should cut down to 70g – equivalent to one and a half sausages.

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