By Sola Ogundipe, Chioma Obinna & Gabriel Olawale
Lagos—THE World Health Organisation, WHO, has issued a health alert stating that consumption of all forms of red meat and processed meat such as pork, beef, hot dog, ham, sausages, corned beef, canned meat and meat-based preparations and sauces among others, carry a high risk of cancer.
The warning which came following an evaluation report by the International Agency for Research on Cancer , IARC, on the carcinogenicity of the consumption of red meat and processed meat, revealed that each 50g portion of processed meat eaten daily increases the risk of colorectal cancer by 18 percent.
The global health body is considering adding red and processed meats to its encyclopaedia of carcinogens, possibly leading to new government legislation demanding warning labels on packs of meat.
A Working Group of 22 experts from 10 countries thoroughly reviewed the accumulated scientific literature, convened by the IARC Monographs Programme, and classified the consumption of red meat as “probably carcinogenic” to humans, based on limited evidence that the consumption of red meat causes cancer in humans and strong mechanistic evidence supporting a carcinogenic effect.
In the evaluation, the association for cancer was observed mainly for colorectal cancer, but associations were also seen for pancreatic cancer and prostate cancer.
Processed meat is defined as meat that has been transformed through salting, curing, fermentation, smoking, or other processes to enhance flavour or improve preservation.
Most processed meats contain pork or beef, but processed meats may also contain other red meats, poultry, offal, or meat by-products such as blood.
Processed meat was classified as carcinogenic to humans, based on sufficient evidence in humans that the consumption of processed meat causes colorectal cancer.
“For an individual, the risk of developing colorectal cancer because of their consumption of processed meat remains small, but this risk increases with the amount of meat consumed,” noted Dr. Kurt Straif, Head of the IARC Monographs Programme.
“In view of the large number of people who consume processed meat, the global impact on cancer incidence is of public health importance.”
The IARC Working Group considered more than 800 studies that investigated associations of more than a dozen types of cancer with the consumption of red meat or processed meat in many countries and populations with diverse diets. The most influential evidence came from large prospective cohort studies conducted over the past 20 years.
“These findings further support current public health recommendations to limit intake of meat,” noted Dr. Christopher Wild, Director of IARC.
“At the same time, red meat has nutritional value. Therefore, these results are important in enabling
governments and international regulatory agencies to conduct risk assessments, in order to balance the risks and benefits of eating red meat and processed meat and to provide the best possible dietary recommendations
The WHO notes that an estimated 8.2 million people die each year from cancer, which is 13 percent of all deaths worldwide. There are more than 100 types of cancer, each requiring unique diagnosis and treatment and a 70 percent increase in new cases of cancer is expected over the next two decades.
But in a reaction, a number of scientists expressed their concerns about the new classification.
One of them is Emeritus Fellow of the Institute of Food Research, Dr Ian Johnson, who noted :
“Although there is epidemiological evidence for a statistically significant association between processed meat consumption and bowel cancer, it is important to emphasize that the size of the effect is relatively small, and the mechanism is poorly defined.
Also reacting, Emeritus Professor of Neurobiology at Cardiff University, Professor Robert Prickard, stated: “Avoiding red meat in the diet is not a protective strategy against cancer.
“Choosing a meat-free diet is a lifestyle choice – it is not vital for health. For the majority of people who currently eat the recommended dietary levels of red meat, which is 70g per day and wish to continue doing so, moderate amounts of red meat can be enjoyed within a healthy balanced diet.”
In Nigeria, controversy surrounding the link between consumption of red meat and risk of development of cancer is well documented.
Professor of nutrition, Prof. Ignatius Onimawo, says consumption of the local skewered beef or chicken popularly called Suya, raise cancer risk.
Onimawo, a researcher and lecturer at the Ambrose Alli University, Ekpoma, Edo State, said research shows a strong link between consumption of suya and increased risk of cancer.
Years back, the WHO had warned that except there is deliberate effort to imbibe healthier dietary and lifestyle habits over the next decade, cancer and other Non Communicable Diseases, NCDs, would increase by more than 27 percent in developing countries like Nigeria, compared to 17 percent in the developed world.
Scientists have often linked red meat with cancer because it contains an unnatural chemical called Neu5Gc, found in beef, pork and lamb. Previous studies have linked red-meat consumption to a number of cancers, especially colorectal, breast, prostate, ovarian and lung cancers.
It is accepted that moderate amounts of red meat can be a source of good nutrition for young people.
Explaining how red meat causes cancer, scientist say the sugar molecule Neu5Gc found in red meat such as pork, beef and lamb, is not found naturally in humans, but it is in most other mammals.
When humans eat meat, the molecule enters the tissues. The immune system attacks it, causing inflammation. Over time inflammation has been shown to cause tumours to form. Previous studies have linked red-meat consumption to a number of cancers, especially colorectal, breast, prostate, ovarian and lung cancers