How it’s made: Fresh leaves are picked and immediately steamed so that they retain their green color. (Oolong tea, which is between a green and a black tea, is briefly exposed to oxygen before it is steamed.)

Beverage benefits: Green tea is a good source of the plant compounds called catechins, the majority of which are epigallocatechin gallate (EGCG), which has been found in studies to reduce LDL (bad) cholesterol. EGCG may also counter inflammation in the body.

If you like lemon, squeezing a slice into green tea may help its beneficial compounds survive digestion, according to research from Purdue University.

There has been some concern that a high intake of catechins can cause liver damage. Recently, the European Food Safety Authority (EFSA) released a report on the safety of catechins from green tea. It concluded that the catechins from green tea as a beverage are generally safe, even if you drink a lot of green tea.

The same does not apply to green tea extract supplements, however. In studies, supplements have been linked to liver damage. The EFSA report notes that daily doses of EGCG of 800 mg or more can trigger liver problems. Though EFSA experts found no indication of liver injuries for doses below that amount, they stated that there isn't enough data to identify a safe dose from supplements. 

According to the EFSA report, the average daily intake of EGCG resulting from drinking green tea ranges between 90 and 300 mg.

There's little evidence that green tea supplements do what they are purported to—namely help with weight loss—so given the risks, it's wise to skip them.

How it’s made: Tea producers roll or crush leaves, releasing an enzyme that oxidizes the catechins. The fermentation creates the brew’s rich flavor and dark color.

Beverage benefits: It may help strengthen your skeleton. Post-menopausal women who regularly drank black tea had higher bone mineral density in the lumbar spine and hip, according to a Japanese study that tracked 498 women over five years.

According to a 2018 report in the journal Biomedicine and Pharmacotherapy, there is strong evidence that black tea can help protect against heart attacks. Possibly this is because the polyphenols in black tea help to relax blood vessels, which prevents them from constricting. 

Reconsider adding that splash of milk, however, at least some of the time—its proteins can bind with some of the beneficial compounds in black tea, reducing your body’s ability to absorb them, researchers say.

• All teas naturally contain caffeine. Black supplies the most (72 mg in 12 ounces—about half that in a same-sized serving of coffee).  

• The World Health Organization has classified “very hot beverages” (158° F or higher) as possible carcinogens. Though drinks are not usually served that hot, it can’t hurt to let your tea cool a bit before drinking it.

• Decaf and home-brewed iced tea have fewer beneficial compounds because of the decaffeination process or dilution with ice, respectively. If you like, double up on tea bags to make up some of the difference, Blumberg suggests.

• Watch out for sugary tea drinks—a 16-ounce Starbucks chai latte with 2 percent milk has 240 calories and a whopping 42 grams of sugars. And it's not just white sugar you should cut back on. Honey, which many people add to tea, is a form of added sugars. It has about 5 grams of sugars per teaspoon (compared with 4 grams per teaspoon for white sugar). The American Heart Association suggests consuming no more than 24 grams of sugars a day for women (about 6 teaspoons) and 36 grams (about 9 teaspoons) for men. So a little drizzle of honey in your tea is fine, but don't pour in too much.