Fear and panic have been spreading among meat lovers this week, on the back of warnings that their favorite food could cause cancer.

According to the International Agency for Research on Cancer (IARC), the cancer agency of the World Health Organization (WHO), which released their findings on October 26, the danger lies in the carcinogens contained in red and processed meats.

After thoroughly reviewing the accumulated scientific literature, a working group of 22 experts from 10 countries convened by the IARC Monographs Program, classified the consumption of red meat as "probably carcinogenic to humans" (Group 2A). This finding is however based on limited evidence that the consumption of red meat actually causes cancer but strong mechanistic evidence supporting a carcinogenic effect. This association was observed mainly for colorectal cancer, but associations were also seen for pancreatic cancer and prostate cancer, according to the WHO report.

The report also classified processed meat as "carcinogenic to humans" (Group 1), based on sufficient evidence in humans that the consumption of processed meat causes colorectal cancer.

However, many have expressed their doubts about whether people all have to become vegetarian in order to escape cancer. According to a Beijing Evening News report on October 27, Fang Yu, director of the Nutrition Department at Beijing Cancer Hospital, said for food to be linked to cancer, certain preconditions need to be considered, such as consumption frequency and volume. Experts say there is no need for meat lovers to panic, if they consume meat correctly.

Meat lovers are in a panic after IARC listed red and processed meats as carcinogenic. Photo: Li Hao/GT

Spreading panic

"When I read the news [that processed meat is carcinogenic], I was happily surfing the Internet with a sausage in my hand," said Song Honghong, a 20-year-old university student in Beijing. "I was frightened and suddenly dropped the sausage on the table."

Sausages have been a regular snack for her throughout her four years at university. Every time she returns from Harbin, Heilongjiang Province, she fills her suitcase with specialty sausages of different flavors produced in her hometown.

"I was frightened at first, because I eat a piece of sausage with almost every meal in my dormitory," said Song.

Canned meat is her favorite when eating a hot pot. "If the WHO report is to be believed, then years of accumulation of the cancer-causing substance in all the processed meat I eat is terrible, and I am doomed, so shall I quit eating it in the future?"

According to the WHO report, red meat refers to all types of mammalian muscle meat. Processed meat refers to meat that has been transformed through salting, curing, fermentation, smoking, or other processes to enhance flavor or improve preservation.

Most processed meats contain pork or beef, but processed meats may also contain other red meats such as offal or meat by-products such as blood. Examples of processed meat include hot dogs (frankfurters), ham, sausages, corned beef, biltong or beef jerky, as well as canned meat and meat-based preparations and sauces.

Jiang Zhiwei, doctor in the General Surgery Department at Nanjing General Hospital, told the Beijing Evening News that food causing cancer is a matter of probability. Although processed meat has a carcinogenic risk, the effects are not instantly felt. Food is only one of the many aspects which are likely to cause cancer.

A staff member from the China Meat Association told the Beijing Evening News that they didn't believe that the WHO report is very scientific and the conclusion was "made in haste." The association is going to cooperate with the National Health and Family Planning Commission to do research on China's morbidity rate as a result of rectal and colon cancer, especially in Sichuan and Hunan provinces, where people love to eat bacon and preserved meat.

"Cancer belongs to difficult miscellaneous diseases and the causes are always hard to  determine exactly, so how can we say it is meat's fault?" said the staff member.

Experts advise that people eat less than 500 grams of processed meat per week, to lower its cancer-causing risk. Photo: Li Hao/GT

Understanding the warning

Yun Wuxin, who has a doctorate in food engineering and is a member of Science Squirrels, an organization for Beijing-based science writers, told the Urban Express on October 25, that carcinogenic substances are grouped and defined according to the abundance of evidence to prove that a certain substance is risky in causing cancer, rather than its level of danger and toxicity.

Yun said Group 1 carcinogenic substances, which are viewed as the most dangerous, means that there is enough evidence to support findings that they are capable of increasing the risk of cancer. It does not mean that they have a super ability and probability of causing cancer. Red meat and processed meat thus belong in Group 2A, which means they are "probably carcinogenic to humans."

The Urban Express report also pointed out that there are many other cancer triggers which the WHO has warned about, like alcohol, tobacco, and areca nut, which all belong to Group 1.

Fang said people need not quit eating meat, but rather it is advised that people take in less than 500 grams of red meat per week, and cut down their consumption of processed meat.

Eating meat healthily

Song said another recent report that frightened her was about a 19-year-old girl who was diagnosed with stomach cancer, allegedly due to her frequent eating of barbecued meat.

"I don't know whether the report is real, but I have turned down two invitations from my friends asking me to eat skewers," said Song. "Eating skewers has become a culture in Beijing and one can easily find a restaurant selling them in a random street. They are delicious, and the fun in our lives will decrease if we quit eating skewers."

According to a report by the People's Daily website in June last year, Ouyang Xuenong, director of the Oncology Department at Fuzhou General Hospital of the Nanjing Military Command, said there is some nutritious value in roasted and barbecued foods. Many of the foods contain microelements and vitamins, and some contain sex hormones and adrenocortical hormones. So while people can benefit from these foods, overeating could be harmful.

Ouyang advises that people only eat roasted and barbecued foods like skewers once a month, and the intake should not exceed 50 grams. "Never eat meat that is burned black or dry," warned Ouyang. "The burned part contains the most volume of cancer-causing substance."

In regular daily life when eating homemade red meat, Ouyang also has advice to give. "People should opt for better cooking methods such as steaming and boiling. The oil should also not be too hot when cooking."

Hu Xingchun, Executive Chef at Suning Universal Hotel in Nanjing, Jiangsu Province told Urban Express that in terms of bacon and preserved meat, people can boil them in hot water, and then choose to steam them.

"Bacon and processed meat are popular dishes in China, and it is impossible to abandon eating them," said Hu. "Another way to healthily eat these foods is to eat lots of fresh fruits and vegetables with it."

Song said she would not mind quitting meat altogether and become a vegetarian, but she would rather try to cut down the daily intake of red meat and processed meat.

"I will replace the beef jerky with healthier snacks such as fresh fruits, and eat less skewers," said Song. "But I can not live without meat, it's one of the biggest joys of my life."

Common carcinogenic agents

The carcinogenic agents listed by the IARC are substances that the ordinary person has access to in their daily lives, and there is evidence or suspicion that these substances could cause cancer. Listed are some examples in each category.

Group 1 Carcinogenic to humans (118 agents)

Wood dust, tobacco smoking and second-hand smoking,  salted fish (Chinese-style), processed meat, outdoor air pollution, untreated or mildly treated Hepatitis B virus (chronic infection).

Group 2A Probably carcinogenic to humans (75 agents)

Consumption of red meat, shift work that involves circadian disruption, frying and emissions from high temperatures.

Group 2B Possibly carcinogenic to humans (288 agents)

Welding fumes, printing processes (occupational exposure), lead, dry cleaning (occupational exposure).

Group 3 Not classifiable as to its carcinogenicity to humans (503 agents)  

Sudan Red 7B, rock (stone) wool, pulp and paper manufacture. 

Group 4 Probably not carcinogenic to humans (1 agent)

Caprolactam

Source: IARC Monographs on the Evaluation of Carcinogenic Risks to Humans

Global Times - Agencies