THERE has been widespread reaction from meat bodies across North America, Europe and Australia following the release overnight of a controversial report linking red meat with cancer risk.
As flagged in yesterday’s pre-emptive story, “Meat industry braces for WHO cancer risk judgement,” the World Health Organisation’s International Agency for Research on Cancer yesterday issued its report on whether there is enough scientific evidence to conclude that eating red and processed meats can be considered a cancer hazard.
The 22-member IARC panel classified processed meats (cured, fermented products like smallgoods) as carcinogenic to humans (Group 1), alongside arsenic and asbestos. It classified fresh red meat as probably carcinogenic to humans (Group 2A). The panel’s decision to classify red and processed meats as cancer hazards was not unanimous, however.
According to the panel, 50 grams of processed meat per day raises the chances of developing colorectal cancer by 18 percent. IARC’s lower classification for red meat reflected “limited evidence” that it causes cancer, but cited associations with pancreatic, prostate and colorectal cancers.
The IARC panel, however, was tasked with looking at hazards that meat could pose at some level, under some circumstance, but was not asked to consider any off-setting benefits, like the nutrition that meat delivers or the implications of drastically reducing or removing meat from the diet altogether.
“For an individual, the risk of developing colorectal cancer because of their consumption of processed meat remains small, but this risk increases with the amount of meat consumed,” said Dr Kurt Straif, head of the IARC Monographs Program.
“In view of the large number of people who consume processed meat, the global impact on cancer incidence is, however, of public health importance.”
The findings supported current public health recommendations to limit intake of meat, said IARC director Dr Christopher Wild.
“At the same time, red meat has nutritional value. Therefore, these results are important in enabling governments and international regulatory agencies to conduct risk assessments, in order to balance the risks and benefits of eating red meat and processed meat and to provide the best possible dietary recommendations.”
In a statement issued this morning in response to the report by Meat & Livestock Australia it said promoting red meat as part of a healthy, balanced diet was important to the red meat industry, MLA was guided by the Australian Dietary Guidelines which recommended 455g/week of cooked red meat as part of a healthy, balanced diet.
The IARC report gave guidance that consumers should refer to the dietary guidelines in their own countries, MLA pointed out.
“Red meat such as beef and lamb is a critical, natural source of iron and zinc, vitamin B12 and omega-3 – essential nutrients needed to keep the body and brain functioning well. Children and women are eating less than the recommended amount of red meat and one in five women have some form of iron deficiency,” MLA said.
“There is no reason to believe that eating beef and lamb as part of a healthy, balanced diet and lifestyle in 100-200g portion sizes (raw weight), 3-4 times a week as recommended in the Australian Dietary Guidelines, will increase risk of cancer,” it said.
“When it comes to prevention of cancer and other chronic diseases such as heart disease and diabetes, the evidence suggests a healthy, balanced diet and active lifestyle is critical – focusing on only one kind of food is not enough.”
Education around such issues was vital, MLA said It consults extensively with experts to ensure the red meat industry’s nutrition communications are evidence-based and relevant to everyday Australians.
Prof Bernard Stewart, Professor with the School of Women’s & Children’s Health at the University of NSW:
Professor Bernard Stewart with the School of Women’s & Children’s Health at the University of NSW is the Chief Scientific Advisor for the Cancer Council Australia. He chaired the committee which conducted the review for WHO’s International Agency for Research on Cancer, and was the only Australian involved in the review.
“No-one’s proposing that we ban bacon, put warnings on hot dogs or take beef off the barbie,” Prof Stewart said.
“But this review provides compelling evidence that the long-term consumption of red meat and/or processed meat increases your risk of cancer.”
He said the report was based on the evidence contained within 1000 previous studies looking at the topic.
“So it is one of the most complex assessments of the medical and scientific literature ever undertaken concerning a particular cancer risk. The findings provide a new degree of certainty for health authorities who produce evidence-based dietary guidelines.”
Dr Rosemary Stanton, OAM
Dr Rosemary Stanton is a nutritionist and Visiting Fellow at the School of Medical Sciences, University of NSW. She was a member of the NHMRC’s Dietary Guidelines Working Committee.
“No one doubts that red meat is a nutritious food. Nor is there any nutritional reason to remove it from the diet. However, in view of the World Cancer Research Fund’s evidence of a convincing relationship between red and processed meat and colorectal cancer, and the results of studies on red meat and cardiovascular disease, the Australian Dietary Guidelines recommend limiting fresh red meat to approximately 450g a week. This is well below the average consumption of 700g of red meat* reported recently by Australian men. (*This figure does not include poultry or fish)
“The guidelines also moved processed meats moved out of the basic food groups to the list of ‘discretionary’ foods. These foods that have no essential role in a healthy diet and should either be omitted or consumed only occasionally or in small quantities. Those who are overweight and those who are small and inactive have no room for discretionary foods.”
Dr Christina Pollard
Dr Christina Pollard is Nutrition Policy Advisor at Curtin University and a Fellow of the World Cancer Research Fund International.
“The IARC assessment are a hazard analysis, answering the question “is there evidence that the substance (agent), in this case meat, is carcinogenic (capable of causing) cancer in humans?” ranking from Group 1 “carcinogenic to humans” to Group 5 “probably not carcinogenic to humans”.
“You cannot compare agents in the same group because the risk associated with exposure is not part of the assessment. Group 1 agents are all hazards, they are capable of causing cancer, but the risk may be different due to different levels of exposure across the population.”
“What do cancer findings mean for Australian population health dietary recommendations? The risk associated with meat (red meat and processed meat) consumption in the Australian diet was reviewed for the 2013 Australian Dietary Guidelines.
“The risk of cancer and other chronic disease as well as beneficial contributions of foods in the overall diet was considered (for meat protein-rich and an important source of iron, zinc).
“Due to risk of colorectal cancer, Australian guidelines do not recommend processed and cured meats and recommendation to limit intake of lean meat or equivalents *to a maximum of 455grams per week of per week (one serve of 65grams of cooked lean red meat a day) for adults.
“Mean daily intake of meat was greater than recommended for men, and the guidelines suggested eating 20% less on average.”
Kathy Chapman, Chair, Nutrition and Physical Activity Committee, Cancer Council Australia.
“The new WHO analysis on red and processed meat and cancer risk is consistent with research commissioned by Cancer Council Australia that was released earlier this month. The study found that 2600 bowel cancer cases each year could be attributed to excess red and processed meat consumption.
“The National Health and Medical Research Council’s current dietary guidelines recommends consuming no more than 65 to 100 grams of cooked red meat, three-to-four times a week. Cancer Council recommends staying within this guideline but we don’t encourage avoiding red meat altogether – lean red meat is a good source of iron, zinc, vitamin B12 and protein.”
“Processed meats, however, are nutrient poor by comparison and more likely to be high in fat, salt and nitrates. This is why we recommend reducing or limiting processed meat intake.
“It’s also important to put the cancer risks associated with red and processed meat into context in terms of other preventable cancer causes. While Cancer Council’s recent research found that red and processed meat accounted for 2600 cancer cases each year, 11,500 cancer cases each year are caused by tobacco, 3900 cancer cases are attributable to obesity and overweight and 3200 are attributable to alcohol. An overall healthy lifestyle, including diet, is important to reduce your cancer risk.”
US industry reaction:
Some of the most strident opposition to the IARC’s findings have come out of the US beef industry.
The North American Meat Institute responded strongly to the classifications, saying the findings defied common sense and contrasted with numerous studies that showed no correlation between meat and cancer.
The Institute said scientific evidence showed cancer is a complex disease not caused by single foods and that a balanced diet and healthy lifestyle choices are essential to good health.
“It was clear sitting in the IARC meeting that many of the panelists were aiming for a specific result despite old, weak, inconsistent, self-reported intake data,” said NAMI’s vice president of scientific affairs Dr Betsy Booren.
Of the 940 agents reviewed by IARC, only one substance- a chemical in yoga pants- had been found to pose no cancer hazard.
“IARC’s decision simply cannot be applied to people’s health because it considers just one piece of the health puzzle: theoretical hazards. Risks and benefits must be considered together before telling people what to eat, drink, drive, breathe, or where to work,” Dr Booren added.
“We will continue to work closely in mainstream and social media to not only respond to the report, but also to share positive resources on red and processed meat nutrition,” she said.
US National Cattlemens Beef Association president Philip Ellis said the IARC group had conducted no new research during their meeting, but simply reviewed existing evidence, including six studies submitted by the US Beef Checkoff.
“hat evidence had already been reviewed and weighed by the medical and scientific community. The science reviewed by IARC simply does not support their decision,” Mr Ellis said.
“We know that there isn’t clear evidence to support IARC’s decision because the Beef Checkoff has commissioned independent studies on the topic for a decade. In fact, countless studies have been conducted by cancer and medical experts and they have all determined the same thing: No one food can cause or cure cancer. But that hasn’t prevented IARC from deciding otherwise.”
“Since IARC began meeting in 1979, these experts have reviewed more than 900 compounds, products and factors for possible correlation with cancer. To date, only one product (caprolactam, which is a chemical primarily used to create synthetic fibers like nylon) has been granted a rating of 4, which indicates it is “probably not carcinogenic to humans.”
“Most other factors or products that have been examined by the body, including glyphosate, aloe vera, nightshift work and sunlight have fallen into three categories: 2B “possibly carcinogenic to humans,” 2A “probably carcinogenic to humans,” or 1 “carcinogenic to humans.”
“It seemed likely from the beginning that we (the beef industry) would find ourselves here. We knew the deck was stacked against us, but for nearly 100 years, the beef industry has supported nutrition research to advance the understanding of beef’s role in a balanced and healthful diet, as part of our commitment to providing a wholesome, nutritious food to Americans.
“We abide by a Nutrition Statement of Principles which guides our actions and communications about beef in regards to nutrition and health. We have long been working on providing credible research that is consistent with what many others outside our industry have already verified: A full, fair and unbiased examination of the entire body of research does not support a finding that red or processed meats cause cancer. This conclusion isn’t mine alone and you can evaluate the information for yourself. We’ve posted the studies reviewed by IARC and other information about the committee’s findings on the website: factsaboutbeef.com.
“At NCBA, our team of experts has also been working with our state partners and other industry organizations to ensure consumers understand what the science really shows.
“As just one example of the work we’ve done, we commissioned a study with the same body of research reviewed by IARC. Our study engaged a panel of 22 epidemiologists from the United States and abroad who were recruited by a third-party research group. Participants in the study averaged 22 years of experience and the full panel had a combined total of 475 years of experience.
“They were provided with a meta-analysis graph which showed data for a specific exposure and a specific human disease outcome, but the specific human disease outcome (colorectal cancer) and exposure (red meat) were not revealed. In other words, they plotted the results of the study findings on a graph, without telling the participants what product the studies examined.
Of the 22 participants in the study, 21 (or 95pc) said their assessment of the magnitude of the association was weak. Of the 22 epidemiologists, only 10 (45pc) said there was even a possible association. Perhaps most importantly, the epidemiologists agreed that, given the evidence provided, there is not sufficient evidence to make public health recommendations.
“Cancer is a complex subject and no one understands fully what causes it or how it can be prevented. Despite billions of dollars spent on research, we only know that no one food can cause or prevent cancer.
“We also know, thanks in part to decades of producer-funded work on the subject, that when people lead overall healthy lifestyles and maintain a healthy weight, they reduce their risks for chronic diseases, such as cancer.
“Our team and state partners are hard at work on this topic to be certain that consumers and their influencers know and understand beef’s role in a healthy diet, regardless of what IARC might say,” Mr Ellis said.
UK research community reaction:
Research labelling processed meats as carcinogenic to humans has been played down by UK food and medical experts.
Professor Ian Johnson of the Institute of Food Research said meat consumption is just one of many factors that could cause cancer.
“IARC has concluded that the evidence in favour of an association between processed meat consumption and cancer, probably because of the ingredients used in processing, meets their criteria for placing this class of foods on the list of recognised human carcinogens. It is important to emphasise however that this classification reflects the strength of the evidence for an effect, not the actual size of the risk.
“Meat consumption probably is one of many factors contributing to the high rates of bowel cancer seen in America, Western Europe and Australia, but the mechanism is poorly understood, and the effect is much smaller than, for example, that of cigarette smoking on the risk of lung cancer. It is also worth noting that there is little or no evidence that vegetarians in the UK have a lower risk of bowel cancer than meat-eaters.”
Professor Tim Key, Cancer Research UK’s epidemiologist at the University of Oxford, said: “We’ve known for some time about the probable link between red and processed meat and bowel cancer, which is backed by substantial evidence.
“This decision doesn’t mean you need to stop eating any red and processed meat. But if you eat lots of it you may want to think about cutting down. You could try having fish for your dinner rather than sausages, or choosing to have a bean salad for lunch over a BLT.”