Or did it? (Btw, I’m hoping to build this into a series about the relative dangers of random shit I hear about out in the world, but I’m a busy person, so we’ll just have to see how it goes.)
The inaugural threat comes courtesy of a coffee-drinking
friend who recently expressed concern that my tea habit* could lead to an early
demise because of some new study linking hot tea and esophageal cancer. The
warning was caveated with a recommendation that I check the specifics before
making lifestyle adjustments, so I did just that and will now answer all your
burning question on the subject.
Why is it just tea
and not coffee?
Because the study only looked at tea drinkers, specifically
people living in the Golestan Province in northeast Iran. The region’s high
incidence of esophageal cancer makes it a convenient place to conduct such a
study, but coffee drinking is not really a thing in Golestan, so tea was the focus. The
authors cite previous literature supporting that consumption of overheated
drinks of all stripes can mess with your esophageal tissue. So, while the
results of this study are about tea, it’s a proxy for throat-scalding liquids
in general. (It’s just that coffee drinkers easily gloss over the words “and
other hot beverages.” Similar to how I regularly ignore the “1-2 glasses” part
of articles about the potential health benefits of wine.)
Does this study tell
us anything new?
That depends on your threshold for novelty. The authors
proudly proclaim that theirs is the first such study to both “prospectively and
objectively” measure tea-drinking temperature. “Prospectively” meaning they
started with cancer-free subjects and followed them over a period of time (10
years, not too shabby) to see if cancer developed rather than asking people already
diagnosed with cancer about their past tea drinking behavior (which is the quicker
and easier but also more bias-ridden approach). “Objective” meaning that, in
addition to gathering self-reported tea temperature preferences, researchers measured subjects’ tea with a thermometer.** Ultimately the goal is to
bump the International Agency for Research on Cancer (IARC) ranking for drinking
beverages at or above 65 C from it’s current status of “probably carcinogenic”
to the more confident “carcinogenic.”
 |
| Probably safe to drink. Image: TheCulinaryGeek |
700 ml is roughly two soda cans volume wise; and 59 C is about
138 F, which is still meaningless because who the hell knows the numeric
temperature of their drinks? Well, thanks to the cheapest digital kitchen
thermometer sold on Amazon, I now do and will share my wisdom. (Though you’ll still
have to rely on my interpretation of the hopelessly subjective qualia of tea
temperature desirability.) Below are the highly scientific results:
88.2 C – freshly poured (Really? The
water was at a rolling boil and I don’t live at some weird altitude, but okay five-dollar
thermometer.)
75.1 C – after five minutes of
steeping, will burn your tongue if you take too big a sip
66.4 C – I added some creamer,
drinkable but still a tad too warm
58.3 C – the perfect cup of tea
52.7 C – still decent
43.7 C – a bit cold, but not “I
forgot I still had half a cup of tea left” cold
A 2008 paper, which I can only imagine was the most exciting
and widely-covered research of its day, took a more mathematical approach to determining
the optimal serving temperature for hot beverages (paper title: “Calculating
the optimum temperature for serving hot beverages”). The authors’ goal was not to prevent cancer but
rather to reduce ER visits for the service industry employees who assemble and
deliver our hot beverages. Over the course of seven pages of formulas and
graphs they concluded that 136 F (57.8 C) was the best bet for balancing consumer
preference with the minimizing of third-degree burns.
Should I be concerned
about all those cups of ≥60 C tea/coffee/mulled wine I already drank?
I’m not, and I’m pretty committed to hypochondria. The main
reason is that esophageal cancer is relatively rare in the US, accounting for only 1% of cancer diagnoses (though I might
feel differently if I lived in Iran, northern China, India, or southern Africa,
where it’s far more common). Doubling the risk of a something is less
impressive when the baseline risk is low. Moreover, things like tobacco and
alcohol consumption seem to be bigger risk factors. So don’t beat yourself up
about your misspent youth of hot tea drinking.
Moving forward, sure, allowing tea to cool slightly is an
easy enough health intervention. But if drinking too hot beverages is the worst
of your potentially disease-causing habits, I’d say you’re living a pretty
wholesome life.
Are you sure it’s not
just the tea itself that causes esophageal cancer?
Nothing in this world is certain. Everything and everyone
has the capacity to deceive, disappoint and betray you. But in regards to this particular study, it’s
hard to say. While they did also look at how much tea subjects consumed, most
of the heavy tea drinkers were also the people who preferred their tea piping
hot, so those variables are difficult to untangle. And due to a combination of
my own laziness and the authors’ assurance that their study is methodologically
superior to its predecessors, I’m opting not to dig too far into the archives
on this one. There is mention of animal studies suggesting that certain compounds
in hot beverages could be a contributing issue rather than just the temperature. So maybe
plain hot water is the safest (and most affordable!) option. You’re welcome to
give it a shot, but I’m going to stick with tea.
* I accidentally quit
drinking coffee a few years back and now start my days with English Breakfast
tea like some kind of commie weirdo pervert.
** The method was to
make two cups of tea, one for the subject to sip and comment on and the other
to be used simultaneously to take temperature readings. Science!
Title Image: Markus Kniebes
