No need to cut down on bacon sandwiches, researchers say
People should continue to enjoy steak, sausages and bacon, experts have said, as they claimed there is no proof red and processed meats cause cancer.
In a controversial move, a team of researchers branded the evidence linking red meat with serious health problems as weak, saying people should carry on as they are – enjoying three to four portions of red and processed meat per week on average.
Their new guidance flies in the face of recommendations from health organisations including the World Cancer Research Fund (WCRF), which has told people to avoid processed meat altogether or eat very little of it, while limiting red meat to about three portions a week.
The WCRF gathered a team of organisations – including from the World Health Organisation – to hit back at the latest findings, saying there is good evidence of a link between red and processed meat and bowel cancer.
At present, the Department of Health and Social Care (DHSC) recommends that anyone who eats more than 90g of red or processed meat per day should try to cut down to 70g or less.
In 2015, the World Health Organisation's International Agency for Research on Cancer said consumption of red meat is "probably carcinogenic" to humans, whereas processed meat is considered "carcinogenic".
And the WCRF said people should avoid processed meat altogether or consume very little of it, while also sticking to three or fewer portions of red meat a week.
But in the new study, published in the Annals of Internal Medicine, a team of international experts said those claims were based on very low-quality evidence.
They came to the same conclusion about the risks from eating red and processed meat as other researchers, but said the findings were so weak they did not warrant people being told to cut down.
The team – which included 14 experts from seven countries – said their analysis offered the "most up-to-date evidence on the topic".
Study author Bradley Johnston, associate professor at Dalhousie University in Canada, said: "Based on the research, we cannot say with any certainty that eating red or processed meat causes cancer, diabetes or heart disease."
The team's conclusion – that most adults should continue to eat their current intake of red and processed meat (about three to four times a week) – is contrary to almost all other guidelines that exist.
Mr Johnston said the team found no real benefit from cutting down below this level.
He said: "From 12 randomised controlled trials enrolling about 54,000 individuals, we did not find a statistically significant or an important association in the risk of heart disease, cancer or diabetes for those that consumed less red or processed meat."
While there was some evidence for a small reduction in risk for those consuming three fewer portions a week, "the certainty of evidence was low to very low," he added.
"Our bottom line recommendation – which is a weak recommendation based on low-quality evidence – is that for the majority of people, not everyone, continuing their red and processed meat consumption is the right approach."
'Putting people at risk'
Dr Giota Mitrou, director of research at the WCRF, said the new interpretation of the research "could be putting people at risk by suggesting they can eat as much red and processed meat as they like without increasing their risk of cancer.
"However, this is not the case.
"The message people need to hear is that we should be eating no more than three portions of red meat a week and avoiding processed meat altogether.
"We stand by our rigorous research of the last 30 years and urge the public to follow the current recommendations on red and processed meat."
In a further statement, the WCRF, the American Institute for Cancer Research (AICR), the American Society for Preventive Oncology, Bowel Cancer UK and the World Health Organisation's International Agency for Research on Cancer (IARC) urged people to stick to the recommendations to limit red meat intake to three portions a week and eat little, if any, processed meat.
They said they disagreed with the latest interpretation of the scientific evidence.
'People should limit red meat intake'
Dr Nigel Brockton, vice president of research at AICR, said: "We stand by the rigour of our research methodology and our cancer prevention recommendation that people should limit red meat intake to less than 12 to 18oz per week and avoid processed meat.
"The underlying results reported by the NutriRECS group are actually consistent with this advice.
"However, their interpretation of the strength of these findings differs from the conclusions reached by the WCRF/AICR continuous update project expert panel.
"Regularly eating processed meat, and higher consumption of red meat, increases your risk of colorectal cancer.
"Suggesting that there is no need to limit these foods would put people at risk of colorectal cancer and further undermine public confidence in dietary advice."
Tim Key, professor of epidemiology and deputy director of the cancer epidemiology unit at the University of Oxford, said: "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.
"The authors here have found the same evidence of an effect but they think it is so modest that it isn't worth recommending we do anything about it."
Dr David Nunan, senior researcher at the centre for evidence-based medicine, University of Oxford, said the experienced team of researchers "likely did a good job and the findings and judgments are likely to be robust and trustworthy".
He added: "As far as I can see, for the majority of important outcomes (death, cancer rates, heart disease), people choosing to eat less meat and those who are told to eat less meat or given less meat to eat have a small benefit, but this benefit might not be meaningful enough to impact on the population levels of these outcomes."
But Dr Marco Springmann, senior researcher on environmental sustainability and public health at the University of Oxford, said: "The recommendation that adults continue current red and processed meat consumption is based on a skewed reading and presentation of the scientific evidence."
In April, a separate study led by Oxford University and funded by Cancer Research UK, found that even small amounts of red and processed meat – such as a rasher of bacon a day – can increase the risk of bowel cancer.
They estimated that eating three rashers of bacon a day rather than just one could increase the risk of bowel cancer by 20%.
For every 10,000 people in the study who ate 21g a day of red and processed meat (about a rasher of bacon or a slice of ham), 40 were diagnosed with bowel cancer
The comparable figure for those who ate 76g a day (about half a steak), was 48.
Cancer Research UK said about 5,400 of the 41,804 cases of bowel cancer seen each year in the UK could be prevented if people did not eat processed meat at all.
Emma Shields, Cancer Research UK's health information manager, said: "Processed meat increases the risk of bowel cancer – there's a mass of evidence that shows this."