Coffee, elixir of the gods.
Studies say drinking it can lower your risk of developing Type 2 diabetes, Parkinson's disease, Alzheimer's disease and mouth cancer. It can prevent cavities. It can make you happier. It can kill a headache. It can make asthmatics breathe a little easier. It can ease the effects on the heart and liver of hard, heavy drinking.
And yet, we are a nation of coffee drinkers and still we have mouth cancer, Parkinson's, Alzheimer's, rotten teeth, unhappiness, headaches, asthma attacks, heart attacks and liver disease. When we go to the doctor, dentist or personal trainer, they almost never write a prescription for a daily trip to Starbucks.
Every day, we sip a steady stream of health news about something we could eat or drink and how it will help save us from Health Nightmare X—or help cause it. Avoid refined sugar. Take fish oil pills. Drink coffee. Don't.
So here's the good news, according to experts who study disease and risk: You can pretty much ignore almost all of these health bulletins, with a few exceptions:
Exercise, eat a balanced diet, don't be fat, drink only in moderation and, whatever you do, don't smoke.
"There are some risk factors that have a major impact. Like, there is no doubt smoking kills millions of people," said epidemiologist John Ioannidis of Tufts University School of Medicine in Boston. "But for most lifestyle and diet choices—I'm not claiming none have an impact, but their impact is likely to be very small, if anything."
This is not to say science is pointless. After all, it was the painstaking work of scientists that conclusively proved that smoking is a health disaster.
But being a good consumer of science news means understanding how scientific studies work. Sometimes, findings that sound spectacular may be completely useless to you—though important to other scientists working on the bigger picture.
For example: A recent study published in the American Journal of Epidemiology followed 39,000 middle-age Japanese people for 13 years and found that the people who reported drinking one or more cups of coffee a day were about half as likely to get oral, pharyngeal or esophageal cancer as the others.
That sounds like a great excuse to order another cappuccino because these are some of the deadlier cancers—only 16 in 100 people diagnosed with esophageal cancer live five years after diagnosis, according to the American Cancer Society.
But before you do, consider that the study's findings tell us only about relative risk—the cancer risk for coffee drinkers in relation to non-coffee drinkers. Half as much risk sounds like a lot, but the bottom line is that very few people in either group got cancer.
In other words, the absolute risk is low, coffee or no coffee.
So you decide. Is it worth taking up daily coffee drinking to turn your already small risk of oral, pharyngeal or esophageal cancer into an even smaller risk? Keep in mind that buying one small Dunkin' Donuts coffee a day adds up to almost $600 a year in Chicago. With cream and sugar, it also means absorbing an extra 43,800 calories a year.
Ask yourself also: Could some other factor be responsible for the decreased cancer risk? Maybe something else that Japanese coffee drinkers tend to do or experience is what's protecting them against cancer. Researchers try to take into account such confounding factors—such as income levels or health issues—but they don't always think of everything.
"Ask yourself, who are the coffee-drinking people? Did these people smoke less? Have these questions in the back of your mind," said Sherry Seethaler, author of "Lies, Damned Lies, and Science: How to Sort Through the Noise Around Global Warming, the Latest Health Claims, and Other Scientific Controversies."
Wednesday, February 18, 2009
Conflicting studies about health risks and benefits can drive you crazy. Here's how to sort through the science.
