Understanding Carcinogen Classifications: Risks and Exposures

Carcinogens, which cause cancer, are classified by the International Agency for Research on Cancer (IARC) under the World Health Organization (WHO) into three risk levels: Group 1, 2, and 3. While some carcinogens, such as tobacco, radiation, radon, and asbestos dust, have an established causal relationship with cancer, most have not been studied through large-scale human research. As a result, precise information is lacking, such as how much exposure is required to develop cancer.

▲Benzo[a]pyrene=Benzo[a]pyrene, a substance classified as a Group 1 carcinogen by the WHO, is produced when animal-based foods such as meat and fish are burned. But how much must one consume to develop cancer? According to the European Food Safety Authority (EFSA), one would need to ingest approximately 2 tons per day for it to pose a significant cancer risk.

However, inhalation of smoke from burnt food poses a greater risk, as it can significantly increase the incidence of lung cancer. Professor Lee Se-hoon from the Department of Hematology and Oncology at Samsung Medical Center emphasized, "The higher the cooking temperature and the more oil is used, the greater the risk of benzo[a]pyrene exposure. Therefore, food service workers and chefs should take extra precautions."

▲Red Meat=The WHO classifies red meat as a Group 2 carcinogen. According to WHO findings, consuming 100g of red meat daily is associated with a 17% increase in the risk of colorectal cancer. However, this conclusion is based primarily on animal studies, and no large-scale studies have been conducted on humans. Due to this limitation, many experts question the reliability of this claim. For reference, the average daily meat consumption of South Koreans is 89.7g.

▲Processed Meat=Processed meat is classified as a Group 1 carcinogen, which includes ham, sausage, bacon, and other processed meats. According to a report by the American Institute for Cancer Research, excessive consumption of processed meat is a definite risk factor for colorectal cancer. The key word here is "excessive." The report states that consuming 50g of processed meat daily increases the risk of colorectal cancer by 18%, as well as the risk of prostate and pancreatic cancer. However, Koreans' average daily intake of processed meat is only about 6g, meaning there is little cause for concern.

▲Hot Beverages Above 65°C=Hot beverages are classified as a Group 2 carcinogen. This classification is based on a study published in the Lancet by the International Agency for Research on Cancer (IARC), which examined the risk of esophageal cancer associated with beverage temperature. The study found that individuals who regularly consumed tea at temperatures above 65°C had an eightfold increase in the risk of esophageal cancer.

However, many experts, including the American Council on Science and Health (ACSH), argue that this classification is overly cautious. In reality, the primary risk factors for esophageal cancer are alcohol consumption, smoking, and chronic gastroesophageal reflux disease (GERD) rather than the temperature of beverages.

▲Acrylamide=Acrylamide, a Group 2 carcinogen, is found in coffee, French fries, potato chips, and fried sweet potatoes. Since its discovery in 2002, there has been ongoing debate regarding its potential harm to human health. Animal studies have shown that high concentrations of acrylamide can induce cancer, but research on its effects in humans is still inconclusive. To date, no study has definitively proven that acrylamide directly causes disease in humans.

Professor Hoon-Jeong Kwon from Seoul National University's Department of Food and Nutrition stated, "For Group 2 carcinogens designated by WHO, the causal relationship and threshold levels are not clearly defined." He emphasized that over 90% of elderly individuals in Korea have insufficient animal protein intake, and therefore, "there is no need to be overly sensitive to WHO standards."