Tea offers a spectrum of health perks but there’s a catch — the bottled kind may fall short on beneficial nutrients. Brewing your own isn’t too difficult and costs much less.

Polyphenols, antioxidants naturally present in tea, are believed to be responsible for the drink’s benefits. An analysis of six supermarket brands of bottled teas showed that, in some cases, you would have to drink approximately 20 bottles to equal the antioxidants in one home-brewed cup.

According to the study, presented at the 240th National Meeting of the American Chemical Society, one cup of tea brewed from a regular tea bag contains, on average, between 50 and 150 milligrams of polyphenols. In comparison, the six bottled brands that were analyzed contained 3, 4, 13, 40, 43, and 81 milligrams in one 16-ounce bottle.

High calorie content from added sugars is another potential downside of bottled teas. And, some contain artificial flavoring.

Health Perks of Tea

Assuming tea is properly brewed, its benefits are plentiful. Research shows that it lowers these risks:

1. Heart disease: One study found that drinking one to two cups of black tea daily lowered risk for atherosclerosis by 46 percent, and more than four cups daily lowered risk by 69 percent.
2. Cancers: Different studies have found links between green or black teas and less prostate, rectal, colon, digestive, urinary tract, pancreatic, and skin cancer.
3. Vision loss: Animal research shows that the eye absorbs nutrients from green tea, and these protect against glaucoma.
4. Infection: L-theanine, another beneficial substance in tea, improves resistance to bugs. A study found that people who drank five cups of black tea daily, for two to four weeks, quadrupled levels of interferon, part of our natural defense system.
5. Cavities: Flavonoids, another health-promoting tea ingredient, may reduce dental plaque and strengthen tooth enamel.
6. Kidney stones: In a study of 81,000 women, risk dropped by 8 percent per daily cup of tea. In another study, of 45,000 men, risk dropped by 14 percent per daily cup.
7. Osteoporosis: Several studies have found that people who drink tea have stronger bones.

Brewing Basics

Traditionally, tea is brewed with loose leaves, but you can cheat for convenience and use bags. As a lifelong tea drinker who owns a real teapot and other brewing accessories, I can honestly say that tea bags can make a terrific cup. The key is to have the bag sitting in a dry cup, boil water in a kettle, and pour once the water reaches boiling point — not a moment earlier. Let steep until it reaches a strength you enjoy.

In dire circumstances, I’ve tried microwaving a cup of water and then drowning a tea bag in it. The result has always been horrible. I have no idea why that should be, but so it is.

If you like iced or carbonated tea and don’t want to make your own, there’s another way to cheat: Buy a high-quality, healthy brand like Steaz (www.steaz.com). For example, Steaz Zero Calorie Sparkling Green Tea contains 120 milligrams of natural tea antioxidants and is sweetened with stevia.

When choosing teas, you can splurge on a variety of gourmet leaves or bags. However, basic ones from a supermarket, like Lipton or Tetley (my favorite), can make a really good cuppa.