Coffee vs. tea: benefits and risks.(Health)

While tea lovers revel in tea's likely health benefits, coffee drinkers worry that anything as deliciously stimulating as java must be unhealthful. But research shows that coffee is generally safe in moderate amounts and might have surprising benefits of its own: Large observational studies have linked regular coffee consumption with reduced risks of type 2 diabetes, gallstones, and possibly Parkinson's disease. Still, both green and black against cancer, heart disease, tea trump coffee for protection and possibly osteoporosis.

HOW THEY PROTECT YOU

Coffee. Caffeinated and decaf coffee each contain antioxidants and other substances that may help regulate blood sugar; that might explain the apparently reduced diabetes risk. Certain compounds in coffee also appear to help prevent bile from crystallizing into gallstones. And caffeine may cut the risk of Parkinson's by boosting supplies of the brain chemical dopamine, at least in men.

Tea. Habitual tea drinkers' reduced cancer risk might stem from tea's high antioxidant capacity. Tea might protect the heart by relaxing blood vessels, inhibiting clots, and reducing cholesterol levels. And researchers speculate that the fluoride and estrogen-like substances in tea may bolster bone density.

HOW MUCH IS TOO MUCH?

There's little or no evidence that drinking substantial amounts of tea is harmful to the average person. As for coffee, moderate intake--one or two cups a day--seems to be safe for most people. At least one large study has suggested that such consumption protects the heart, though the underlying reason is not clear.

Some research, however, has linked drinking three or more cups of coffee a day with increased heart risk. Coffee can raise the level of homocysteine, an amino acid that might harm the arteries. And coffee's high caffeine content--typically twice as much as black tea and several times that of green--may raise blood pressure, though that hasn't been proved.