Green Tea: Good or Bad?

There are countless questions dietitians get are asked on green tea--- Is it good for me? How much should I drink? Does it have caffeine? Will it help me lose weight? We’ll address all your concerns on this popular beverage so you can decide if it’s right for you.

green tea cup

Photo by: Katarzyna Malecka/iStock

Katarzyna Malecka/iStock

There are countless questions dietitians are asked about green tea: Is it good for me? How much should I drink? Does it have caffeine? Will it help me lose weight? We've got the scoop on this popular beverage -- here's what you need to know.

About Green Tea

For centuries green tea has been used in various ways including as a stimulant, diuretic and to help improve heart health. Of the three tea varieties, green tea is the only one that doesn’t undergo fermentation upon harvesting (black and oolong do). The leaves are steamed or pan-fired in order to prevent the fermentation process. Some varieties of green tea include Gunpowder, Hyson, Sencha, Dragon Well and Matcha.

Nutrition Info

Green tea contains the highest amounts of polyphenols, powerful antioxidants that have been shown to help fight disease. If you find that is has a bitter flavor, that’s from the catechins which are a specific type of polyphenols specifically found in green tea. Adding lemon to your tea can help cut the bitterness.

The main vitamins and minerals you can find in green tea include vitamin C, energy-boosting B-vitamins, vitamin E and fluoride (for strong teeth and bones).

What Studies Show

Numerous studies have been published indicating that green tea may play a role in reducing the risk of heart disease. One such study was published in 2006 in the Journal of the American Medical Association found that folks who drank green tea over a period of 11 years had a lower chance of getting a stroke. Scientific studies have also shown that green tea may help with cancer of the lungs, breast, prostate, stomach, colon and skin. The tea has also been found to help improve cognitive function among older adults.

Weight Loss

Green tea contains compounds known as alkaloids (like caffeine) which provide a stimulant effect and do help speed up metabolism. But don’t go downing packages of green tea just yet — it only increases it a small amount.  Several studies have linked green tea and green tea supplements (in the form of pills and extracts) to weight loss of about 1 to 5 pounds (depending on the study and the form of green tea that was taken).

Besides not being regulated by the FDA, many of the green tea supplements promising weight loss have a laundry list of active ingredients that may interact with medications and other herbal supplements. This is especially true if you have a heart condition -- caffeine (and other stimulants) and a bad heart just don’t mix. Green tea and green tea supplements (i.e. pills, extracts) have also been shown to interact with medications prescribed for kidney disease and psychological disorders. It’s important to always consult a physician before drinking green tea regularly or taking green tea supplements.

Bottom Line:

Studies have shown beneficial effects of green tea and can be part of a healthy diet. The healthiest option is drinking a cup (or two) of green tea a day. Stay away from the supplements and weight loss gimmicks – they can be dangerous and they’ll leave your wallet thinner than they’ll make you.

TELL US: Do you drink green tea?

Toby Amidor, MS, RD, CDN, is a registered dietitian and consultant who specializes in food safety and culinary nutrition. See Toby's full bio »

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