Be advised: the Annals of Internal Medicine has issued what may be considered a "Code Brown."

Do not be alarmed. Continue normal activities. Not to worry about suspicious persons, mad cows, unattended packages, canceled flights or anything, really. This alert says: Don't worry, be happy.

Drinking caffeinated coffee, you see, may significantly reduce your risk of type 2 diabetes, the most common form of the disease.

The "Code Brown" remains in effect unless and until it is contradicted by further studies of coffee and health, and then studies of the studies of the studies.

No human can keep track of all the coffee studies, but stay tuned for further information.

At, the estimate is that more than 19,000 scientific studies of coffee have been completed to date.

A few years have passed since that count. So that number may not include the Dutch study of 17,000 adults, which found that people who drank at least seven cups of coffee a day were half as likely to develop type 2 diabetes as those who drank two cups or less.

The new study, conducted by the Harvard School of Public Health and others, affirms the Dutch study, but with a bigger pool of people. Or perhaps we should say a bigger "puddle."

Or not. You see, according to dietitian Susan Moores of St. Paul, Minn., recent studies also suggest that coffee may not actually deserve its infamy as a diuretic. That one little cup before the road trip may not necessarily result in a complete tour of all restrooms along the New Jersey Turnpike.

Such notions may merely be matters of perception.

It seems coffee may also not deserve its association with high blood pressure, heart disease, high blood sugar or cancer - according to studies of the last decade or so. These have considered chronic effects of coffee drinking, which are less well understood than the short-term effects.

The latest study is just part of this wave of good news for coffee drinkers. Perhaps the insomnia, heart palpitations, tremors, stomach acid, panic attacks and bad breath may not be the ominous signals one might have thought.

"The perception has been if you drink too much coffee, it's not a healthy habit," says Dr. Frank Hu, a professor of nutrition and epidemiology at the Harvard School of Public Health and co-author of yesterday's report in Annals of Internal Medicine. "This perception is not based on scientific evidence. The opposite may be true."

Hu cites previous studies associating increased coffee drinking with reduced risk of colon cancer, Parkinson's disease and gallstones.

Repeat: Hu and other authors of this study say you should continue normal activities. Do not drink more coffee. Do not rush to Starbucks to ask about intravenous coffee equipment. As a result of this "Code Brown," you must do, well, nothing.

"It's not a magic bullet," says Hu.

The new study considered the coffee-drinking habits of 126,000 adult men and women over the course of between 12 and 18 years. The subjects drank coffee. They drank more coffee. They took bathroom breaks. Every two to four years they filled out forms answering questions about their coffee drinking and their health, including questions about type 2 diabetes mellitus.

Researchers corrected for other risk factors, such as lack of exercise and obesity. They found that those who drank coffee - especially those who drank six cups or more of caffeinated coffee a day - were at significantly lower risk for type 2 diabetes than those who drank no coffee. The results were slightly more pronounced for men than women.

The effects with decaffeinated coffee were less pronounced, and the effect of caffeinated tea was not found to be significant.

Type 2 diabetes represents about 9 of 10 cases of the disease, which afflicts 6 percent of Americans. In type 2, the body either does not make enough insulin - a hormone which helps the body use sugar - or does not properly use the insulin it does produce. The result is high blood sugar and a range of health complications: heart disease, stroke, high blood pressure, kidney disease, blindness.

At the moment, those at greatest risk for this diabetes are overweight or have some family history of the disease. The new study finds that caffeine seems to reduce the risk by playing some role in metabolizing blood sugar.

This contradicts previous studies, which found that in the short term, infusions of caffeine raised blood sugar. Much as the short-term caffeine hit raises blood pressure, but coffee drinking over the long term is not associated with chronic high blood pressure.

Why, though, is not exactly clear.

More study is needed, says Hu. Coffee, he says, is "such a fascinating beverage."

Ah, yes, the coffee bean is to the nutrition scientist much as Mars is to the astronomer. So much in our language, our culture, yet so mysterious. At last report, more than 850 chemical compounds had been identified in the humble bean. Some contribute to taste and aroma, some do not. Some evidently have health benefits because they contain antioxidants, some merely make your breath stink. The morning brew contains the whole stew - a complex substance acting on a complex human system in a complex environment.

No wonder dietitian Moores must verbally shake her head at the wonder of the latest word from the research front.

"With every study we can find that says it does good things, or for every two, there's one that says it does not do such good things," she says.

One may, therefore consider this a "Code Brown" day. Do not necessarily make it a grande double espresso. Await further studies.

A Hill of Beans

Coffee numbers

107,000,000: Number of coffee consumers in the USA in 2001

52: Percent of American adults who drink coffee daily (28 percent drink coffee occasionally)

3.3: Number of cups per day consumed by the average U.S. coffee drinker

$164.71: Amount average coffee consumer spends per year on coffee

9: Number of ounces in average cup size

35: Percent of consumers who drink coffee black (62 percent add creamer or sweetener)

64: Percent of coffee consumed at breakfast (28 percent between meals; 8 percent at other meals)

$5.88: Cost of four tall (12-ounce) Starbucks coffees in Baltimore

$0.05: Estimated cost per 8-ounce cup prepared at home (compared to 16 cents for milk, 44 cents for beer, 25 cents for bottled water, 79 cents for orange juice and 13 cents for soft drinks)

Coffee talk

Women are more excited about coffee varieties currently available and a higher proportion of women indicate that drinking coffee is a good way to relax.

Women are more price-conscious about coffee than men.

Men appear to more readily attest that coffee helps them "get things done."

Coffee quote

"If it weren't for the coffee, I'd have no identifiable personality whatsoever."

- David Letterman - Meredith James and Julie Furlong

Sources:, Coffee Science Source, National Coffee Association of U.S. Inc.,

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