Reading the Coffee Beans
No matter where you get your news--TV, daily paper, website, magazine, or radio--the media are choked with conflicting medical information. From low-fat diets to hormones, chocolate milk to pain relievers, calcium to vitamin pills, readers are confused. There may be no greater offender than the mixed messages that pour in regularly about what some consider America's national beverage--coffee. On this score, last week's report in the Journal of the American Medical Association on the purported link between coffee drinking and heart attacks is a godsend. For this article serves up coffee as a model for consumers in making sense of much of the health news that seems at odds.
Keep in mind that coffee has been cast as vice and virtue for hundreds of years. When it first seeped into Europe from Arabia around 1600, it was known to mess with the mind. Blaming its klatches for inciting loose gossip and rebellion, a few tyrannical monarchs destroyed coffeehouses of the day. Legend also has it that advisers to Pope Clement VIII pressured him to ban coffee as an infidel threat. The pope insisted on tasting the delicious elixir and baptized it rather than outlawing the drink.
We've learned since why coffee incites such passion: A shot of java stimulates an adrenaline rush and jazzes up nerve connections, making for more energy and sharper brains. Even mood improves, making coffee a welcome waker-upper and a late-night necessity when the workday gets long. It also brings athletes an edge, as it enhances response time and muscle function. Chock-full of anti-oxidants and tied to a lower incidence of Parkinson's and Alzheimer's disease, it is ready to be baptized again--this time as a veritable health food.
Qualms. Yet there's long been a nagging fear. Caffeine can make a heart race or skip a few beats and can add a few points to blood pressure. But the real coffee concern is the research that shows its association with an increased risk for heart attacks. That qualm has quieted of late, however, as other studies indicate that effect is more guilt by association with cigarette smoking.
But the JAMA study is a spoiler if you look at some of the headlines: Researchers found that independent of smoking, two to three cups a day coincided with a 36 percent increase in heart attacks in roughly half of the coffee drinkers who carried a normal variation of a gene that makes a protein formidably named CYP1A2. One variant of this gene hard-wires caffeine metabolism to be slow, so caffeine lingers in the body and its level increases with each additional cup. Four or more coffees in these slow metabolizers upped the chances of a heart attack to 64 percent. By contrast, headlines generally ignored the other coffee drinkers, who were the fast caffeine metabolizers and had fewer heart attacks. That's even compared with those who drank little or no coffee, suggesting that moderate coffee intake has a protective effect. In short, it all depends on how your body handles the stuff.
The protein involved is a master enzyme in the liver. It not only breaks caffeine down but is also a critical part of the metabolism of other bioactive compounds like estrogen and many pharmaceuticals. Thus it is no surprise at all that different people react differently to coffee and other compounds. These latest coffee findings remind us that we all have individual metabolism quirks, some genetic and some acquired, which contribute to our personal traits and tastes. And variations still unrecognized are bound to account for many of the inconsistent medical reports. For example, there are post-menopausal women for whom estrogen replacement works wonders, while others feel awful or gain no benefit. Calcium and vitamin D metabolism, and the need for supplements, vary among those susceptible to fragile thin bones, compared with those who have strong bones.
Even if it makes you jittery, think coffee the next time you hear dissonance about food on your dining table or pills in your medicine chest. Remember, it's more than the "coffee." Your personal chemistry plays a role, too. Until we doctors have simple and reliable tests to profile the genes and other markers that define metabolism, prudence is your best guide. Read beyond the headlines. Talk to your doctor. Listen to your body. Whether it's a cup of coffee, a hormone patch, a candy bar, or a daily statin, moderation is best in all things. At least, that is, until we can tell you for sure just what your own personal metabolism demands or will let you get away with. Third cuppa joe, anyone?
This story appears in the March 20, 2006 print edition of U.S. News & World Report.