Author Archives: Even Zheng

How Harmful are Cancer-causing Meats?

You may think the title of this post is an oxymoron: if something is cancer-causing, it must be pretty harmful, there is no question! This is also what most people thought when they read the headline few days ago, about the fact that processed meat has been classified as a “definite” cause of cancer, and red meat a “probable” cause. But what many people didn’t realize is the difference between “evidence” and “risk”. Granted, the announcement on the consumption and effects of meat made by International Agency of Research on Cancer (IARC) is based on more than 800 studies and is definitely backed up by scientific evidence, but the overall risks of processed and red meat are still much lower in comparison to other cancer-causing things such as smoking, thus much less harmful than what we perceived them to be.

Grilled and Smoked Meat | Copyright @ 2010 by DeusXFlorida, Flickr

To clear up some definitions, “processed” meat is meat that has been modified to extend its shelf life or change the taste using methods such as smoking, curing, or adding salt or preservatives, according to a BBC article, while “red” meat includes beef, lamb, and pork. There is now evidence that bowel (or colorectal, colon) cancer is more common among people who eat the most processed and red meats, with the most convincing evidence being a study by researchers at the World Cancer Research Fund (WCRF). The study showed that people who ate the most processed meat had a 17 % higher risk of developing bowel cancer compared to those who ate the least, which is equivalent to 10 more people developing bowel cancer among 1000 people.

The IARC classifies a particular cancer risk as one of five categories, representing how confident they are that it causes cancer. Processed meats have been given group 1 classification, which “definitely” causes cancer, while red meat is in group 2A and “probably” causes cancer. However, even though processed meats is now in the same category as alcoholic beverages and tobacco, it does not mean they are equally dangerous. To put things into perspective, Cancer Research UK estimated that about 19% of all cancers were caused by tobacco, and only 3% are caused by eating processed and red meat.

This video summarizes the news, the limitations, and some perspectives on this topic: YouTube Preview Image

-credit: PBS NewsHour

Now that it seems like there is no need to suddenly turn vegetarian if you didn’t intend on becoming one, it could also be wise to cut down on processed and red meat. Perhaps eating smaller and fewer portions of red meat, choosing chicken and fish over beef and lamb, or adding more vegetables and pulses is some thing to consider doing. After all, red meat does have its nutritional benefits too: high content of iron, vitamin B12, zinc, protein, all are important for our body. And with more and more food becoming carcinogenic, a moderate diet of any kind is always more beneficial.

-Even Zheng

I commented on Bowen Zhao’s post on “Benefits of Eating Insects”, Doris Stratoberdha’s post on “Who’s this stranger starring at me?”, and Sogand Goharpey’s post on “Smarter by playing a music”.

“Asian Glow”: More than Embarrassment

Have you ever gone out to the bar or had a couple of drinks with friends of East Asian heritage (Chinese, Japanese, and Korean)? If so, you would have probably noticed that at least one of their faces turned red after only a few sips of alcohol. This is called the “Asian Glow”. As the name suggests, it refers to the common reaction of Asians turning red after drinking alcohol.

Asian Glow: Before and After | Image: Brooks PJ, Enoch M-A, Goldman D, Li T-K, Yokoyama A

According to U.S. Department of Health & Human Services, our body breaks down alcohol in two steps, facilitated by two enzymes that speed up the break down process. The enzyme alcohol dehydrogenase (ADH) converts alcohol into a toxic intermediate called acetaldehyde (C2H4O), then the second enzyme aldehyde dehydrogenase (ALDH2) turns it into acetate (CH3CO-2) and releases the toxic compound out of the body.

Breakdown of Alcohol in Two Steps | Credits: ethanol, acetaldehyde, acetate molecules from Wikimedia | Edit: Even Zheng

Unfortunately, about 80% of all East Asians are born with overactive ADH in their stomach and liver, breaking down alcohol up to 100 times faster into the toxic acetaldehyde. In addition, about 50% of East Asian have a deficiency in ALDH2 enzymes, which means it takes much longer for the body to clean out the residues of alcohol. Simply put, their body skips right past the pleasant effect of alcohol and experiences body rash, nausea, dizziness, and all the “hangover symptoms” much faster. Now we know who to blame, it’s all because of genes!

I remember a time I was at my friend’s place for a small gathering. It was only half an hour into the chitchat when my friend pointed at me and said, “Your face looks like a stop sign!” followed by everyone’s laughter. At that time, I literally had half a can of beer. If anybody can relate, someone has probably also told you to practice and increase your tolerance level, but you might want to give that a second thought.

What most people don’t know is that the toxic acetaldehyde is actually a cancer-causing agent. An article published by The New York Times revealed that researchers believe the condition of turning red after drinking alcohol may link to increased risk of throat, stomach, and esophagus cancer, which are some of the most deadly types of cancer. This is especially dangerous for people who have developed a high tolerance to acetaldehyde and became heavy drinkers.

A Time Magazine article suggested that the hereditary trait may have evolved in the ancient Chinese population as a survival strategy to allow people to drink alcohol made from fermented rice, while protecting them against alcoholism. Regardless of its credibility, there is indeed a lower rate of alcoholism among people with the deficiency, for obvious reasons. Before we find any way to replace the inactive enzyme or develop safe medications, it is the best to just avoid drinking altogether. It might make your parties a little “lame” on Friday nights, but on the bright side, you now have a good excuse to tell your friends when they want to go out for a drink right before your exam.

Here is a video to help you understand the metabolism of alcohol: YouTube Preview Image

Credit: Science of Nutrition

-Even Zheng