To eat, or not to eat, red and processed meat
Areport by theWorldHealth Organization’s International Agency for Research on Cancer has said there is enough evidence to rank processed meats— such as ham, bacon and sausages— as “group 1 carcinogens”, because of their causal link with bowel cancer. Processed meats are meats that have been transformed through salting, curing, fermentation, smoking, and other processes to enhance flavor or improve preservation.
Expectedly, the IARC report has caused uneasiness among the public worldwide and its conclusion has been violently rejected by the meat industry.
“For an individual, the risk of developing colorectal cancer because of… consumption of processed meats remains small, but this risk increases with the amount of meat consumed,” said Kurt Straif, head of the IARC monograph program.
The IARC report evaluated data from more than 800 different studies of cancer risks in humans, over 700 of which involved red meat and more than 400 involved processed meat. A team of 22 international experts reviewed the evidence, and it placed processed meats in Group 1— Carcinogenic toHumans— the same category as cigarettes. However, red meat (beef, pork, lamb) is assigned to Group 2A— Probably Carcinogenic toHumans.
AlthoughWHOclassifies processed meats and cigarettes both in the highest category of carcinogens, the classification reflects only the strength of the evidence to support this claim; it is not a reflection of the level of risk.
The difference between the risks posed by meat with or without being processed is highly significant, because processing adds several substances to the meat products that may be the real cancer causing agents. The report also doesn’t make the difference between the effects of consuming meat with several additives and meat to which much fewer additives are added.
Not all countries process meat in the same way. In some industrialized countries such as the United States, several products are added to meat and even more to processed meat, unlike countries such as Argentina or Australia where meat has fewer additives.
Among the substances added to meat are sodium benzoate, sodium propionate and benzoic acid, which, in some conditions, have shown to have carcinogenic potential. Nitrites and nitrates are routinely added to meat to inhibit the growth of bacteria and enhance color. When nitrites combine with some amino acids, cancer causing compounds called nitrosamines are produced.
Antibiotics are part of the diet of US livestock to make them grow faster and prevent disease outbreaks. However, antibiotics in animal feed have proven to be a significant factor for the increase in antibiotic resistance among humans. Sulfites have been widely used as preservatives in food to maintain their color and prolong shelf life. But sulfites can also trigger asthma attacks among people who are sensitive to them.
In a 2010 report, the US Department of Agriculture’s Office of the Inspector General found high residues of copper, arsenic and other heavy metals and veterinary drugs in beef distributed for public consumption. In addition, traces of pesticides can also be found in some animal feeds.
Although these are just a fewof the substances that can be found in regular and processed meat the obvious question is: Are meat and processed meat carcinogenic, or are the substances added to them responsible for their becoming potentially carcinogen?
These considerations point to the need for the food regulatory agencies to be stricter in their control of food quality and also the need for more exhaustive studies comparing consumption of meat and processed meats with and without harmful additives. Until the results are out, popular wisdom is still the best advice: eat everything in moderation.
The author is an international public health consultant.