Co-authors of the paper – ‘Carcinogenicity of consumption of red and processed meat: What about environmental contaminants?’ – José L Domingo and Martí Nadal from Rovira i Virgili University (URV) in Tarragona, Spain, highlighted that the IARC paper did not address the potential threat of carcinogenic environmental pollutants already present in raw or unprocessed meat.
N-nitroso-compounds (NOCs), polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic amines (HAAs) are acknowledged as well known carcinogenic chemicals present in meat processing, such as curing and smoking. The paper claimed that processing and cooking meats may produce these known or suspected carcinogens.
“However, due to the practically unavoidable presence of other carcinogenic compounds already present in raw or unprocessed meats, we believe these chemicals are not the only potentially carcinogenic substances in meat and meat products,” the report said.
These other substances are well-known environmental pollutants that include some heavy metals, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs).
The URV paper recognised that the health risk posed in meat products are mainly related to micro-pollutants and/or process-induced toxicants. “Micro-pollutants are generated by human activity, or may come from veterinary or plant treatments, being eventually transferred to foodstuffs, including meats. In turn, process-induced toxicants are formed during food processing such as heating or smoking.”
It is highlighted that many of these potential toxicants are fat soluble. As a result, any fatty food often contains higher levels of micro-pollutants than vegetable matter. “Consequently, an issue of concern related with a frequent consumption of certain foodstuffs (including of course meat and meat products) is the health risks potentially derived from exposure to chemical pollutants contained in those food items.”
In an effort to explore how cooking techniques can alter the pollutants, the scientists’ cooked different cuts and kinds of meat in different ways. Research concluded that although cooking processes could modify the levels of chemical contaminants in food, “the influence of cooking on the pollutant concentrations depends not only on the particular cooking process, but even more on their original contents in each specific food item.
“As most of these environmental pollutants are organic, cooking procedures that release or remove fat from the meat should tend to reduce the total concentrations in the cooked meat.”
Although cooking processes only slightly influenced the content of toxic metals in food, concentrations of environmental pollutants depend not only on particular cooking methods, but even more so on the contents of contaminants in specific foods before they are cooked.
“Generally, cooking procedures that release or remove fat from the product should tend to reduce the total concentrations of the organic contaminants in the cooked food. This might be of special relevance in the current context on the carcinogenicity of consumption of meat and meat products, at least, with respect to the most widespread environmental pollutants.”
In conclusion: “The results of our own studies and those from other researchers suggest that, although certain cooking processes could change (decrease or increase) the levels of chemical contaminants in food, pollutant levels depend on not only the particular cooking process, but even more their original contents in each specific food item.”
As most of the environmental pollutants were organic, it was noted that cooking procedures releasing or removing fat from meat tend to reduce the total concentrations of these contaminants in meat. “Anyhow, we have noted that chicken generally contains less organic contaminants than red meats.
“Once again, and as with most foods, the reduction of the daily intake of fats contained in meat and meat products will be useful for a healthy diet.” The authors recognised that this reduction may prevent “not only cardiovascular but also carcinogenic risks”.