If you want to make sure you're getting all the benefits of tea, then make sure you brew your own.

That's because all the terrific polyphenol antioxidants that make tea such a great beverage choice practically disappear once the brew is bottled, according to a new study. In some cases, you may need to drink up to 20 bottles of store-bought tea just to get the polyphenols you'll find in a single fresh-brewed mug.

You won't read about that on the label!

Researchers collected 49 samples of six brands of bottled tea bought from grocery stores. Half of those tested contained virtually no antioxidants. The other half had small amounts--in some cases, so small that drinking them would provide no real antioxidant benefit.

Overall, the 16-ounce bottles had between 3 and 81 milligrams of polyphenols, according to the test results presented at the National Meeting of the American Chemical Society in Boston.

Tea brewed at home, on the other hand, will usually contain between 50 and 150 milligrams of polyphenols per cup.

And those polyphenols hold the key to many of tea's benefits--including the benefits I've written to you about from time to time. Tea--especially green tea--has been linked to cancer prevention, heart and vision health and a lower risk of diabetes, dementia and depression.

Some studies have even found that tea drinkers live longer.

I'd be willing to bet that the patients enjoying all the benefits in those studies weren't gulping down Snapple.

Polyphenol levels aside, there are plenty of other reasons to skip bottled teas, which are usually overflowing with some pretty awful ingredients--including sugar and other sweeteners and artificial flavors.

The bottles themselves could even be poisoned, since they may contain the hormone-like chemical bisphenol A.

But of course, the bottom line here is that tea is so incredibly easy to make on your own that it's stunning to think there's any market at all for bottled brew--much less the massive billion-dollar industry that exists today.

After all, you don't even need a kettle and a stove to make a cup of tea--just a teabag, a mug, some water and a microwave. And brewed on your own, tea costs pennies a cup.

Ounce for ounce and dollar for dollar, real tea offers one of the best nutritional boosts you'll ever sip.

Just do like the kids say and "keep it real."