Warning to diabetics who drink tea and coffee read the title of an article that appeared in my mailbox the other day. I regularly get tea and tea science feeds from a variety of sources to keep me informed. As you can imagine, this one caught my attention. As I read the article, I was struck by the fact that it never mentioned the word tea other than in the title. After completing the article, I decided to find the original study to get more information. After considerable effort, I was finally able to track it down.
What I have been able to glean from the study is the following: The research subjects were 10 habitual coffee drinkers. Subjects took 500 mg of caffeine in capsules (equivalent to four cups of coffee and considered “moderate” in comparison to their normal levels of consumption) each day for three days, while monitoring their insulin and glucose levels as they went about their normal lives and eating their “normal” diets (except that researchers had them drink “Boost Plus” – a supplement drink – for breakfast each day and told them to eat “similarly” for the other two meals – whatever that means). As the article reported, they found that, on average, the subjects’ daily glucose levels increased overall, as did their post meal levels, compared to placebo. Dr. Lane’s conclusion: “Our study suggests that one way to lower blood sugar is to simply quit drinking coffee, or any other caffeinated beverages.”
So let’s look at what we know. The article title warns diabetics (and by association anyone concerned about their blood sugar levels) to not drink coffee or tea. There is neither mention of tea in the body of the news article nor in the research study. The caffeine that subjects take is in capsule form (500 mg) and the equivalent of four cups of coffee or 12 – 16 cups of tea (use the lower number for teas containing the higher levels of caffeine – more with the lower caffeinated teas). We know that tea contains lower levels of caffeine and many different constituents in addition to caffeine. We also know that some of these phytochemical constituents mitigate the physiological effects of the caffeine in the body and, in fact, have a relaxing effect. In addition, we know that still other constituents (esp. the catechins) have been the subject of numerous studies, most of which have shown significance in tea’s ability to decreases glucose levels as well as increase insulin sensitivity.
So what can we conclude from all of this? As the road captain in Cool Hand Luke was made famous for saying; “what we got here… is failure to communicate.” This type of sensationalist headline coverage of scientific research is par for the course for the media. They tend to pick out information that they feel will elicit the most emotional response from their readers, regardless of its accuracy. Often this is misleading at best and completely false at worst. This is precisely why it is incumbent upon us to take what we read with a grain of salt until we have had an opportunity to investigate it ourselves or get the information from a trusted source. Caveat lector.
photo credit: caffeine by Single Serve Coffee