In the past, the supermarket offered exactly two kinds of tea: black and herbal. Then different flavors of black tea to joined the fun. Then the herbal teas expanded, too, and before you knew it, your local supermarket tea selection looked like an Indian bazaar. So what's the deal with all these different kinds of teas -- and do they really do what they promise?

1. Black tea

Black tea is the most oxidized type of tea. It's strong in flavor and contains more caffeine than any of its counterparts. If you see something called Crimson Tea in an Asian supermarket, it's the same thing. Black tea retains its flavor for several years, and holds the title of most popular tea in North America. Like all kinds of tea, black tea boasts health benefits due to antioxidants (although adding milk reverses some of its positive effects).

2. Herbal tea

Simply put, herbal tea is any hot beverage made from plants other than tea leaves. There are many different varieties of herbal tea, each with its own purported health benefits. In fact, many types of herbs do have positive effects on the body, so look into the composition of your favorite herbal teas.

3. Green tea

Green tea leaves come from the same plant as black tea leaves. They are substantially less oxidized, meaning that green tea has less caffeine than black tea. Like herbal kinds of teas, green tea is associated with many health benefits. But in spite of its increasing popularity, the only health benefit science has proven is a mild reduction in your chances of developing heart disease and certain kinds of cancer.

4. White tea

Like other kinds of tea, white tea leaves come from the tea plant, but they aren't oxidized at all: they're picked fresh. Although white tea has high caffeine levels, it's also one of the healthiest teas out there. Studies show that white tea contains high antibacterial properties and also that it has more of the amino acid theanine, which is the substance in tea that makes you feel relaxed.

So it turns out that tea isn't as simple as it seems. Next time you're browsing the kinds of tea in your supermarket, keep these facts in mind and let them guide your selection.