Commentary: Christmas turkey or yule ham for this festive season? Here’s what you need to know about red meat
The festive season is around the corner.
The festive season is around the corner.
Perhaps, like me, you are looking forward to tucking into some gourmet festive food. Roasted Christmas turkey, honey-glazed yule ham…who could resist? Go ahead, enjoy.
But if you are feeling especially indulgent and are looking for a second helping, choose the turkey.
So, why not the ham?
For a host of health reasons, cancer risk being one of them.
It is a question of red and white. Red meat versus white meat. Ham from pork is red. Turkey is white.
The World Health Organization's (WHO's) International Agency for Research on Cancer (IARC) considers fresh red meat a probable cause of cancer (category 2A carcinogen).
Processed red meat is worse, considered a definite cause of cancer (category 1 carcinogen).
That puts processed red meat in the same category as tobacco smoking (another category 1 culprit).
The robust conclusions were drawn after analysing more than 800 different clinical studies; 700 of these provided data on fresh red meat and 400 studies provided data on processed red meat.
The IARC attributes 34,000 cancer deaths worldwide to diets high in processed meat annually. If the attributable risk from fresh red meat were to be included, this figure rises to 50,000 annually.
Red meat refers to beef, pork and lamb/mutton. Fish and poultry (chicken, duck and turkey) are white meats.
Some people in Singapore wrongly believe that duck is red meat and pork is white meat based on their colours.
Processed red meat is meat that has been transformed, often through curing and smoking, to items such as bacon, ham, sausages, luncheon meat and Chinese barbeque dried meat (bak kwa).
I bet this list has snared several of your comfort foods.
What’s the beef with red meat? In a word: Haem.
Haem is a protein with iron bound to it found in high concentration in red meat. Haem is what gives it the reddish colour. Haem is also the reason why red meat is a rich source of nutritional iron.
Haem, unfortunately, also acts as a catalyst in the formation of carcinogens. It converts excess fat and protein in meats to toxic substances (aldehydes) through a process known as lipoperoxidation.
Haem also aids the conversion of nitrites/nitrates into cancer causing nitrosamines. Nitrates are often added to processed food to serve as a preservative, though such substances can also be naturally occurring.
Haem in red meat and high levels of nitrates in processed forms are obviously an explosive combination.
To top this off, the high temperature that meat is exposed to during popular methods of cooking red meats, such as roasting and grilling, leads to the generation of more carcinogens in the forms of heterocyclic amines and polycyclic aromatic hydrocarbons.
So, how much red meat, fresh or processed, is considered bad? Is there a threshold below which we are safe?
There isn’t a safe limit, a red line beyond which we must not step.
The relationship between red meat consumption and cancer risk is one of dose-response. In plain language: The more we eat, the higher the risk.
The IARC estimates that an average increase in daily consumption of 100g of fresh red meat raises lifetime risk of colorectal cancer by about 20 per cent.
Half that amount daily, that is 50g, of processed red meat does the same damage.
And the damage goes beyond just colorectal cancer; stomach cancer, pancreas cancer and prostate cancer risk rates also increase.
A common plea I hear from red meat lovers, to counter this negative narrative on eating red meat is this: They eat only organic red meat. Or this: They eat only processed red meat with no artificial preservative added.
So, are these smart ways to skirt around the potential health risks associated with red meats?
Organic red meat has the same haem content as meat from other methods of animal husbandry. Processed red meat with no artificial preservatives often are preserved with natural substances, such as celery juice, with high concentration of nitrates. Natural or artificial, nitrates are nitrates.
Are specific red meats safer than others?
The IARC could not gather enough information from currently available medical literature to reach a definite conclusion if the risk differs between the different red meats. Hence, dietary modification to reduce colorectal cancer risk will have to target all red meats at this point.
Are specific age groups, racial groups or genders more vulnerable to the detrimental effects of eating red meat?
Again, unfortunately, the available research data does not allow the IARC to narrow the purported risk to specific groups. The conclusions have to be generalised to all populations.
What of patients who have already developed colorectal cancer? Is cutting down on red meat consumption still important for them?
On this question, the clinical research data are conflicting. While there are reports of a reduction in the relapse rate and an improvement in survival observed in colorectal cancer patients who cut their intake of red meat, other studies failed to see a similar correlation.
Nonetheless, prominent medical professional organisations in the United States, such as the National Comprehensive Cancer Network (an alliance of 31 leading cancer centres in the US) and the American Institute for Cancer Research recommend that survivors of cancer reduce dietary intake of red meat.
While controversies exist on the potential nutritional benefit versus the health risk of red meat and not everything is black-and-white, the scientific evidence so far does indicate that where cancer risk is concerned, there is a difference between red and white.
ABOUT THE AUTHOR:
Dr Wong Seng Weng is medical director and consultant medical oncologist at The Cancer Centre (Singapore Medical Group) at Paragon Medical and Mount Elizabeth Novena Specialist Centre.