No new cancer-risk evidence in report
THE report by the World Health Organisation agency warning of the link between processed meat and an increased cancer risk has taken the globe by storm and resulted in a flurry of negative publicity around meat and meat products.
According to the International Agency for Research on Cancer, every 50g portion of processed meat eaten daily increases the risk of bowel cancer by 18%. Red meat was ranked lower, evaluated as probably carcinogenic to humans, possibly causing bowel cancer.
Although the report published a review of scientific findings, it has nevertheless led to misleading reports.
The agency represents the opinion of 22 scientists from 10 developed countries. Its evaluation did not introduce new evidence. It was based on existing scientific literature, and its opinion is not based on consensus in the global scientific community.
Two key issues weaken the agency’s findings: majority agreement on the findings, and that a hazard — not a risk — assessment was done.
The final classifications were based on a majority agreement and not on unanimous consensus. Such evaluations are historically based on unanimous consensus.
The agency conducts hazard analyses, not risk assessments. This distinction is important. The study considered whether meat under some circumstances could be a hazard. Each substance is classified according to its potential hazard.
Processed meat has been placed in Group 1: carcinogenic to humans; red meat in Group 2A: probably carcinogenic. Since the 1970s, the agency has reviewed more than 900 products, substances and exposures. More than 400 have been identified as carcinogenic, probably carcinogenic, or possibly carcinogenic.
But frequency, intensity and potency of exposure to any hazard plays a role in determining the potential risk.
The agency’s report indicates a risk for processed meat. It warned against eating 50g a day, saying it could increase the risk of colorectal cancer by 18%.
Cancers are among the leading causes of morbidity and mortality worldwide, with about 14-million new cases and 8.2-million cancer-related deaths in 2012.
Nearly 1-million cancer deaths per year are attributed to tobacco smoking, while 600,000 a year are as a result of alcohol consumption. Another 200,000 cancer deaths a year are as a result of air pollution.
The most recent estimates by the Global Burden of Disease Project show that across the globe, 34,000 cancer deaths per year are attributed to diets containing high intakes of processed meat.
In this context, the number of cancer-related deaths attributed to excessive consumption of processed meats compared to other hazards is relatively small.
After the report’s release, Oleg Chestnov, WHO assistant directorgeneral, said some foods needed to be limited as part of a healthy diet, but did not need to be eliminated.
He said the document linking red meats to cancer was aimed mainly at politicians, so they can regulate the sector within their borders.
Most governments promote balanced approaches to diets based on scientific evidence. They encourage moderate consumption of foods from all the food groups.
This is the sensible approach. Scaring people is not.