Tea and Coffee, . . . and Lung Cancer?

Say something I already agree with and I’m right there with you. Say something opposed to my beliefs, and well, sure you have a point but.

Right? We argue that we are independent thinkers and open minded. Yet.

It’s sooo much easier to hear only what we want to hear. We don’t have to think—or evolve—or change.

Back in 2009, a study demonstrated that

people were in general twice as likely to select information that supported their own point of view as to consider an opposing idea, with two thirds going for supportive views as opposed to a third going the other way. (Paton 2009)

Lead researcher, Dolores Albarracín, observed that

people tended to stay with their own beliefs and attitudes because changing them might prevent them from living the lives they were living. (Paton 2009; emphasis mine)

How true is this?!

So here you go. What is your immediate reaction?

Study suggests link between tea/coffee consumption and lung cancer risks.

In this case, I am so totally wanting to stick with what I already believe because there’s no way that I’m wanting to change my belief—because that would prevent me from living the life I am living, a life spent drinking copious amounts of tea and coffee.

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Side A, aka The “Wrong” Side, i.e., the side that I don’t like, causing me to want to poke a bunch of holes in their research although it’s hard to argue with a study that tracked a million-plus people.

Researchers in the U.S. and Asia collaborated in a massive investigation into possible links between tea/coffee and lung cancer.

The project incorporated 17 individual studies and 1.2 million participants, and sought to sidestep the complicating issue of smoking by also tracking those who have never smoked. Results were reported at the March 31 American Association for Cancer Research meeting.

The threshold for consumption was 2 or more cups of coffee per day, or 2 or more cups of tea per day. Unfortunately I have access only to an abstract of the presentation, but according to Live Science’s interview with Jingjing Zhu, the lead author of the study, what constituted a “cup” varied among the studies, and consumption was recorded only at the beginning of the 8-plus-year studies (Saplakoglu 2019).

I wonder what the high end of consumption was and where most people fell on that spectrum. Also, what tea was consumed?

Of course, this study pooled data from 17 studies, so undoubtedly those individual studies had tight controls, with variances factored into the overall analysis.

Still, because the authors concluded that

a high consumption of coffee or tea was both associated with an increased risk of lung cancer regardless of race or smoking status (Zhu 2019)

I’d sorta like to know what “high consumption” actually entails, and if they mean just two 6- or 8-ounce cups, I’m not sure I would consider that to be “high.”

On the other hand, if “high” does mean as little as 12 ounces a day, that probably puts most tea and coffee drinkers into the increased risk category.

And this risk for lung cancer apparently is substantial: 37% higher for nonsmoker tea drinkers and 41% for nonsmoker coffee drinkers over nonsmokers who don’t drink tea or coffee (Zhu 2019).

Can this be?

With numerous studies demonstrating the health benefits of tea and coffee, including indications that they may help prevent or even reverse cancer, can they actually cause cancer instead?

Looking closer at the coffee results, Live Science’s interview with Zhu reports that the risk was greater for decaf coffee drinkers than for regular coffee drinkers, suggesting that the caffeine is not the problem but perhaps something in the coffee bean roasting process, which has been implicated in other studies from what I remember. Further, secondhand smoke was not addressed at all.

And the interview unfortunately provided no further details about the tea aspect of this study.

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Side B-1, aka The “Right” Side, i.e., the side that I like because it supports what I’m already doing.

A 2008 study analyzed 1,000+ people with lung cancer and 1,000+ controls to tease out cause and effect with green and black tea, decaf tea, and coffee. The results were dramatically different to those of “Side A.”

Compared to people who didn’t drink tea or coffee at all or who drank less than 1 cup per week (Fujiwara 2008):

• those who drank more than 1 cup/week of green tea reduced their odds of lung cancer by 64%
• those who drank more than 1 cup/week of decaf black tea saw a 36% reduction
• those who drank more than 1 cup/week of black tea saw no change
• those who drank decaf coffee saw no change
• those who drank more than 3 cups/day of coffee saw a 30% higher odds—except that “when drinkers of other tea/coffee beverages were excluded from each model in order to explore the independent effect of each type of tea/coffee,” this association did not hold up.

Fujiwara concludes that drinking more than only 1 cup of green or decaf black tea a week seems to protect against lung cancer.

Can this be? Only 1 cup of tea per week has an effect at all? And why is a study comparing 1 cup of tea per week versus 3 cups of coffee per day? Is it only me or would it make more sense to compare like with like, either 1 cup per week or 1 cup per day or 3 cups per day, whatever, as long as it’s somewhat comparable.

And why do green and decaf black have protective effects but not black? But the apparent effect of green tea is substantial!

Side B-2, another The “Right” Side study.

A more recent study looked at 1,000+ people with lung cancer and ~1,400 controls, analyzing possible links between the cancer and coffee and black tea. In looking at consumption, they factored in how often people drank coffee/tea, how long they’ve been doing so, how much they averaged per day, and cumulative amount.

Their results were also at odds with the “Side A” study:

Our results do not provide strong support for associations between consumption of coffee and black tea and lung cancer. (Pasquet 2016)

Again, I have only an abstract to go on here, but the authors write that consuming more tea/coffee, or consuming it for a longer time period, had no clear impact on risk, nor did a person’s smoking level or being male or female.

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So do you find a side that you totally agree with, discounting the other? Or do you perhaps find yourself here:

Side C, aka On the Fence, or Undecided, or Waiting for More Research

I’m here, but largely because I believe that results can be misconstrued and always need verification and explanation. With the preponderance of findings that suggest tea and coffee are beneficial to us, those on the “other side,” that Side A, might have a lot to overcome, both scientifically and on the PR level.

Still, such a large study—with so many people involved and seemingly very clear findings—should give us pause.

These results didn’t materialize out of nothing, so is it as simple as it sounds? Do tea and coffee really increase the risk for lung cancer? And if so, what is it that causes that? As we saw with the tea/coffee and esophageal cancer link, where it seems to be the temperature of the beverage and not the choice of beverage that causes the harm, we have to be careful about what we take away from the headlines.

Meantime, while I wait to hear more on this subject, I’m brewing another cup of tea—perhaps living dangerously, perhaps living prudently, depending on the study, but either way, I’m living the way I want to live.

Sources:
–Fujiwara, A., “A case-control study of tea/coffee consumption and lung cancer risk,”  Texas Medical Center Dissertations (via ProQuest), 2008.
–Pasquet, R. et al., “The consumption of coffee and black tea and the risk of lung cancer,” Annals of Epidemiology 26(11), September 2016.
–Paton, N. “Why we only listen to what we want to hear,” Management Issues, 7/2/2009.
–Saplakoglu, Y., “There may be a link between coffee and lung cancer, study suggests,” LiveScience, 4/3/19.
–Zhu, J., et al., “Associations of coffee and tea consumption with lung cancer risk: A pooled analysis of 17 cohort studies involving over 1.2 million participants,” American Association for Cancer Research annual meeting, 3/31/19.