I've read a lot about the supposed health benefits of tea (especially green) and coffee [in regards to] cancer, heart disease, and Parkinson's disease [risk].
Any hard data on this?
[If so, do the health benefits] apply to all kinds of teas and coffees?
What about decaf varieties?
-- Corey Clark
There is plenty of data in the scientific literature showing the health benefits of coffee.
Coffee beans contain a wide array of antioxidants, polyphenols, and health-promoting compounds.
Consistent consumption of 16 to 24 ounces of coffee a day has been linked with decreased risk of Parkinson's disease, liver cancer, type-2 diabetes, and cardiovascular disease.
Additionally, the antioxidants in coffee have been shown to reduce inflammation and inhibit cellular tumor growth.
What these studies basically show is that healthy individuals (these recommendations do not apply to pregnant women) who drink coffee regularly do not need to be concerned with cutting it out of their diet for health reasons.
That said, some percent of the population is sensitive to caffeine, so they are wise to avoid it.
Luckily, both caffeinated AND decaffeinated coffees and teas share the same amount of flavonoids and antioxidants.
Speaking of teas, all varieties (green, white, and black) offer plenty of flavonoids and antioxidants. Herbal teas, however, offer significantly lower amounts.
The biggest issue with these beverages is what people are putting into them (syrups, tablespoon upon tablespoon of sugar, mounds of whipped cream, etc.) that often turns them into calorie, sugar, and fat-laden drinks that do more harm than good.