What does a cancer classification mean for the red meat industry?

Fiona Greig, B+LNZ Inc nutrition manager The announcement of the World Health Organisation (WHO)’s International Agency for Research on Cancer (IARC) classification of red and processed meat in October created shock waves through media outlets around the world, writes Fiona Greig, Beef + Lamb NZ Inc’s nutrition manager.

The New Zealand red meat industry was well prepared with full knowledge of the IARC evaluation and understanding of what it involved, due to the fact we sit within a global network of meat nutritionists and scientists. Members of the International Meat Secretariat’s Committee on Human Nutrition and Health each contributed with their nation’s insights, to ensure we were equipped to think globally and act locally when the IARC announcement was made. Here in New Zealand, much interest was given to what the industry reaction was to the results.

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 the formation of N-nitroso compounds (NOC) and polycyclic aromatic hydrocarbons (PAH) during curing and smoking processes, meat’s haem iron content, and heterocyclic aromatic amines (HAA) and PAH when cooking at high temperatures, which I understand to be defined as over 200°C. This, therefore, poses the question of whether a similar association occurs with white meats, but this was not covered in this report.

Recipes and food styling by Kathy Paterson
Beef pitas. Photo B+LNZ Inc. Food styling by Kathy Paterson.

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, that is  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.

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.

Until 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.

This article has appeared in Food NZ magazine (December 2015/January 2016) and is reproduced here with permission.

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