Wednesday September 30, 2009 | 2 comments
Make no bones about it, understanding the health benefits of tea is a challenge—communicating your hard-won understanding to others is trickier still. And yet—as tea professionals and tea drinkers—we dance our way onto this conversational tightrope nearly every week. We strive to keep our words measured, our evidence balanced, and our message conservative—to inform our patrons and friends with integrity. But what happens when even our most innocuous conclusions are met with glaring contradiction?
Just such a thing happened to me last week. On Thursday morning, I visited my inbox and was greeted by two web article headlines seemingly at odds. The first, entitled “Scientists Link Green Tea with Improved Bone Health,” discussed encouraging new findings from the Journal of Agricultural and Food Chemistry. The second, entitled “Bones May Suffer From Green Tea Consumption,” mentioned cautionary results from a study published in the Journal of Nutrition.
You can add this bone duel to a long list of tea health benefit paradoxes, imagined and real. Caffeine purportedly raises blood pressure, but drinking tea has sometimes been found to lower it. Certain studies show that tea has promise against certain forms of cancer, and then in other studies it does not. One study shows that milk compromises the health benefits of tea and another tells us not to worry. Does tea promote anemia? Dehydration? The curiosities are endless—diabetes, obesity, neurodegenerative disease, immune system function—and there are competing answers for all. We chance upon headlines that promise to resolve our burning questions, only to be left with some version of that famous shrug of the shoulders, “Further studies are needed.”
The New York Times weighed in on such contradictory conversations in 2008: “But as with any product used to excess, consumers often wonder about the health consequences. And researchers readily oblige. Hardly a month goes by without a report that hails coffee, tea, or caffeine as healthful or damns them as potential killers. Can all these often contradictory reports be right? Yes. Coffee and tea, after all, are complex mixtures of chemicals, several of which may independently affect health.”
I, for one, have learned to embrace the complexity, to accept the fact that two different studies—one looking at the femurs of live lab mice and another looking at the bone cells of rats in vitro—can reasonably come to what seem like opposite conclusions. If we peek closely, we can see that the studies only offer evidence and speculations on very tiny pieces of the bone-health puzzle. They hardly aspire to their headlines—and this is where all of the trouble begins.
Let’s see this in action on a different level. Take a moment to read this 2007 article from Time. Notice how the opening and closing lines seem to suggest that green tea is a healthier choice than black tea:
“The next time you’re offered a choice between Earl Grey and green tea, you might want to go green.”
“In the meantime, if you’re drinking tea, it might not be such a bad idea to go green.”
Now read the entire article and notice that there is no evidence mustered to support these statements. This limited (14 subjects) study looked only at green tea and caffeinated water—and yet the author has no trouble hinting that green tea will do more for your heart health than black tea. At least this headline is a question rather than statement.
All this goes to show that we must read our news with care and that we must know that tea health benefit headlines are often designed more to capture our attention than to demystify our most complicated ailments. The contradictions are inherent to the teacup, and I wouldn’t have this complex mixture of chemicals any other way.
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Hooray! Because you have said this well. The media is to blame for a lot of the trouble with doubts about tea. But the science isn’t necessarily unsettled. Not only are some studies focused on minutiae, as you’ve pointed out here, but also the reality is there are bad studies. And there are scientists out there trying to prove doubtful hypotheses. In the case of tea, there’s no reason to try to be conclusive with research because there’s seemingly unlimited funding for studies.
Yes, yes, yes. Great post. I hadn’t really considered that each study looks at only one small element of tea, rather than examining the whole plant. I know that the herbal medicine community has known for decades that it takes the whole plant to provide a balanced effect from an herb. When the pharmaceutical companies single out one constituent and then they synthesize it, leaving out the hundreds of complimentary compounds, it contributes to the unfortunate side affects of their drugs.
So what can we do ourselves with all the confusion? I trust my body to tell me how it feels when I drink tea. I do not find it to be dehydrating despite the consumption of 6-8 cups a day. I don’t feel it stimulates me in the evening as it doesn’t contribute to sleep difficulties. It appears that other people have different reactions however. Learn to read studies with a different focus. Just because it’s written by scientists, doesn’t make the general statements that often appear, entirely accurate. And remember, the job of the media is to capture your attention -not necessarily to provide the most valid information.