Comment: Science lost in translation – how the cancer report story unravelled

Fiona Greig, nutrition manager, Beef + Lamb NZ IncLabour weekend marks the time New Zealand meat retailers and consumers alike prepare for the transition to barbecue season. Special occasions celebrated with steaks and sausages are lined up as the silly season approaches. But on returning to work after the long weekend, New Zealand was hit with headlines that would make any meat producer want to stay in bed, writes nutritionist Fiona Greig.

These headlines stemmed from the UK tabloids, which carried speculative articles in the days leading up to the World Health Organisation (WHO)’s International Agency for Research on Cancer (IARC) announcement on its cancer classifications for red and processed meat.

The IARC monograph programme is not easy to explain. Over the last 30 years, approximately 900 agents have been classified in one of five levels attempting to rank the certainty of the relationship between exposure to an agent and cancer.  Only one of the 900 has not been found to be linked to some degree. Importantly to this story, the IARC evaluation is based on hazard analysis not risk analysis. A hazard analysis indicates the probability of red or processed meat being capable of causing cancer under certain circumstances, even when the actual risk is very low, as at current exposure levels. In comparison, it does not assess risk, which indicates probability of risk based on the level of exposure, i.e. the amount eaten.  The latter is of far more relevance when considering foods and we know New Zealanders eat red meat and processed meat in amounts well within nutritional guidelines. Not looking at risk analysis also means no consideration is given to the positive nutritional benefits of including meat in a healthy diet.

The IARC classifications were published after just a week of deliberation of the current evidence base by 22 experts from 10 countries. Processed meat was placed in group 1 – ‘carcinogenic to humans’ on the basis of sufficient evidence for colorectal cancer’. Red meat, in group 2a, was labelled ‘probably carcinogenic to humans’ which means red meat was not established as a cause of cancer because the evidence in humans is limited and other influential diet and lifestyle factors could not be excluded.  These include being overweight or obese, smoking, alcohol and a low intake of vegetables, wholegrains and legumes. The mechanisms proposed for these classifications centre on meat’s haem iron content and reactions occurring during cooking. This, therefore, poses the question of whether a similar association occurs with white meats, but was not covered in this report.

With other agents in group 1, including tobacco, the media had a field day telling people eating bacon and sausages was as bad as smoking, when the IARC classification system is not designed to make such direct comparisons. Its role is to look at hypothetical risk, not the size of that risk. IARC did acknowledge the nutritional benefits of eating meat as well as highlighting the risk is small, which is related to the amount eaten and does not carry the same risk as other substances in the same group – but these details don’t make such good headlines.

The question has been raised whether these results will impact the New Zealand meat industry. Whilst the headlines have come and gone and we don’t expect the impact on consumer attitudes to be significant, we need to be wary of the longer term ramifications at policy level.  Every country has its own dietary guidelines, but often relies on the directive of organisations such as WHO. The IARC working group was unable to reach a conclusion about a safe level of meat consumption and considers it’s the role of each country to set their own recommendations based on a careful evaluation of the risks and benefits of red meat for their specific population groups.

Beef-Grain-Salad. Photo B+LNZ IncUntil the full report is published next year, we won’t know exactly how this will influence international health agendas.  Here in New Zealand, the Ministry of Health has just released its latest eating and activity guidelines, which recommend red and processed meats are eaten in the amounts specified by the 2007 World Cancer Research Fund (WCRF) report. The majority of New Zealanders eat within these guidelines and the IARC conclusions do not suggest this needs to change. The WCRF report will be revised in 2017, however, and may draw on the IARC findings.

Both here in New Zealand, and around the world, we are faced with the challenge of ensuring accurate media reporting when it comes to food and health.  Throw in an international authoritative summary and a classification system not well understood by anyone who is not a scientist, and it’s a recipe for disaster – as we witnessed last week.

Radio New Zealand’s Media Watch critiqued the media coverage, which spanned all mainstream television, radio, print and online platforms. This weekly programme reaches approximately 120,000 including journalists. In summary, it highlighted how the details of this report were overlooked in order to produce a ‘good’ media story, leaving consumers perplexed about what really is a safe amount of meat to be eating. Every opportunity was taken by the Cancer Society, as well as us, to deliver the moderation message, but sadly this was lost in the media’s enthusiasm for a compelling story.

Fiona Greig is nutrition manager for Beef + Lamb New Zealand Inc.

 

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