I am a late-comer to coffee – I grew up without it, and only began drinking it in the last five or six years.  I started in earnest on sabbatical in Spain, with espresso, but soon realized that I preferred mightily the medium roast, slightly sweet, high altitude volcanic coffees of Guatemala, prepared either in a French press or carefully controlled drip.  I now count as a coffee snob – even though, as I note each time I am in Palo Alto, the true snobs have long since moved on to teas and probably things I have not heard of yet.

As to coffee and health, I have never quite known what to think.  I am easily moved to engage in selection bias, but I do credit coffee with helping me lose weight in the past few years – at bottom, a form of chemical stimulation that is not sugar.  But as to the larger and longer term effects, I haven’t quite known what to think.  So I was intrigued at the WSJ Personal Journal’s Melinda Beck’s useful and entertaining roundup of recent studies on the effects of coffee on health in today’s WSJ.  Bottom line is cautiously favorable to coffee, with some concerns the other direction (I read it this morning out on the stoop in a pair of gym shorts and nothing else, drinking hot coffee in the mid-morning sun and lapping up the rays – but query, dear readers, is the noon sun in DC on Dec 28 sufficiently strong to produce Vitamin D in the skin?  or am I simply freezing in the 30 degree weather?):

To judge by recent headlines, coffee could be the latest health-food craze, right up there with broccoli and whole-wheat bread.

But don’t think you’ll be healthier graduating from a tall to a venti just yet. While there has been a splash of positive news about coffee lately, there may still be grounds for concern.

This month alone, an analysis in the Archives of Internal Medicine found that people who drink three to four cups of java a day are 25% less likely to develop Type 2 diabetes than those who drink fewer than two cups. And a study presented at an American Association for Cancer Research meeting found that men who drink at least six cups a day have a 60% lower risk of developing advanced prostate cancer than those who didn’t drink any.

Earlier studies also linked coffee consumption with a lower risk of getting colon, mouth, throat, esophageal and endometrial cancers. People who drink coffee are also less likely to have cavities, gallstones, cirrhosis of the liver, Parkinson’s disease and Alzheimer’s disease, or to commit suicide, studies have found. Last year, researchers at Harvard University and the University of Madrid assessed data on more than 100,000 people over 20 years and concluded that the more coffee they drank, the less likely they were to die during that period from any cause.

But those studies come on the heels of older ones showing that coffee—particularly the caffeine it contains—raises blood pressure, heart rate and levels of homocysteine, an amino acid in blood that is associated with stroke and heart disease. Pregnant women who drink two or more cups of coffee a day have a higher rate of miscarriages and lower birth-weight babies; caffeine has also been linked to benign breast lumps and bone loss in elderly women. And, as many people can attest, coffee can also aggravate anxiety, irritability, heartburn and sleeplessness, which brings its own set of problems, including a higher risk of obesity. Yet it’s just that invigorating buzz that other people love and think they can’t get through the day without.

Why is there so much confusion about something that’s so ubiquitous? After all, some 54% of American adults drink coffee regularly—an estimated 400 million cups per day…