A woman pours green tea from a glass teapot.
Green tea is as famous for its potential health benefits as its vibrant color.
The beverage has been around for millennia, used for hydration, ceremony and medicinal purposes, with researchers calling it “the second most popular drink in the world besides water.”
Most recently, green tea has developed a reputation as a superfood and health elixir, with claims that it can impact everything from heart disease and cancer risk to weight loss. But is that true?
Just drinking tea in general is a healthy habit, especially if it’s a replacement for sugary drinks, says dietitian Teresa Fung, Sc.D., co-chair of the department of nutrition at Simmons University in Boston and an adjunct professor at the Harvard School of Public Health.
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“Tea itself is great because it has antioxidants,” Fung tells TODAY.com. “You’re drinking fluids, and when we are getting our fluids from tea, hopefully we are not getting it from soda.”
Regular green tea consumption can be beneficial to people’s health, adds Dr. Jay Lee, a member of the board of directors of the American Academy of Family Physicians.
“Many patients do sort of swear by it and believe that it does help with their sense of wellbeing,” says Lee, who is medical director at Integrated Health Partners of Southern California.
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What is green tea?
Green and black tea come from the same tree, but the tea leaves are processed differently after they’re picked, Fung says.
To make black tea, the leaves are oxidized — allowed to dry and darken — for a longer period. Green tea undergoes much less processing, which preserves the antioxidants in the leaves better, she notes.
Green tea nutrition
Since it’s mostly water, green tea is a low-calorie beverage as long as you don’t add sweetener or cream.
One cup contains the following, according to the U.S. Department of Agriculture:
- 2 calories
- 29 milligrams of caffeine
- 0.5 grams of protein
- 2 milligrams of sodium
Brewed pure green tea has no fat, sugar, carbs or fiber. It contains trace amounts of magnesium, potassium, manganese and riboflavin.
What are the benefits of green tea?
Green tea is special because it contains strong antioxidants called polyphenols, Fung says.
Antioxidants can neutralize free radicals — damaging particles generated when the body performs regular processes we need for life.
Because some of these free radicals are also inflammatory, antioxidants could reduce the risk of inflammatory-based diseases, such as cancer, Fung notes. Catechins are the dominant polyphenols in green tea, with researchers studying their potential to prevent breast, lung, prostate, stomach and pancreatic cancer.
But studies of green tea and cancer in people have had inconsistent results, according to the National Center for Complementary and Integrative Health.
Both green and black tea might have beneficial effects on heart disease risk factors, such as blood pressure and cholesterol, but the few studies done in this area have limitations so no definite conclusions have been reached, the center notes.
When it comes to blood sugar, green tea may be able to reduce it a bit, Fung says. In short-term studies, green tea supplementation “significantly reduced fasting glucose,” but long-term trials are needed, the authors of a 2020 review and meta-analysis wrote.
A surprising benefit of green tea is that it naturally contains fluoride, which prevents tooth decay, because the tea tree extracts the mineral from the soil, Fung says. One study found matcha green tea powder had the highest concentration of fluoride of various types of teas tested.
Does green tea lead to weight loss or reduce belly fat?
No, Fung says. It contains caffeine, which can temporarily increase metabolic rate a little, but “it’s really it’s not going to be enough to do anything,” she explains.
Green tea extracts don’t produce meaningful weight loss in adults who are overweight or have obesity, and don’t help people maintain weight loss, the National Center for Complementary and Integrative Health notes.
“People think if you drink a few cups of green tea, you’ll see the fat melt away,” David Nieman, director of the Human Performance Lab at Appalachian State University, told Consumer Reports. “That’s just not going to happen.”
Is it OK to drink green tea daily?
Yes, up to eight cups per day is believed to be safe to drink, according to the National Center for Complementary and Integrative Health.
Drink at least three cups a day to get the health benefits, Fung says.
If you’re sensitive to caffeine, you’ll want to fine-tune the amount so that you’re not overdoing it and start to feel sick, Lee advises.
“Modest amounts of caffeine, if it’s something that someone is consuming regularly, shouldn’t be an issue.”
A cup of green tea has about a third of the caffeine found in a cup of coffee.
Drinking green tea plain is traditional, but you can add lemon or honey to it if that’s your preference, Fung notes. She’s not a fan of green tea in chai latte form, which uses milk and sugar, and contains lots of calories.
Green tea extract vs. drinking green tea
The experts recommend brewing your own tea and drinking it rather than taking green tea extract supplements.
You get the flavor, and it’s more enjoyable to slow down and savor a cup of tea, both Fung and Lee say. You also meet your fluid needs.
“I’m generally in favor of avoiding pills when you can,” Lee notes.
Then, there’s the issue of what’s actually in the nutritional supplements, which aren’t regulated by the U.S. Food and Drug Administration. Antioxidants are sensitive to oxygen, so Fung wonders how many would still be active after the green tea is processed and transformed into supplement form.
Liver problems have been reported people who took green tea extracts in pill form, so people with liver disease should consult a health care provider before using products with green tea extract, the National Center for Complementary and Integrative Health cautions.
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