Nutrition Articles

The Truth about Green Tea

A Health Powerhouse or Mostly Hype?


Components of Tea: Catechins and Caffeine
Flavonoids are dietary compounds found in tea and other foods such as wine, cocoa, fruits and vegetables. Flavonoids determine the color and taste of food and may be involved in healthy body functions. The average U.S. adult consumes 189.7 milligrams of flavonoids each day, most of which (157 mg to be exact) come from tea. While there is currently no recommendation for flavonoid consumption, experts are in the initial stages of discussion regarding recommendations for these dietary components. Tea contains approximately 100-300 milligrams of flavonoids per serving, depending on the type of tea. The main type of flavonoids found in tea are catechins. Because the green tea variety is less processed, it contains more catechins than black tea does. Therefore green tea and green tea extracts have received the most research regarding possible health benefits and will be the focus of this particular article. Research has primarily investigated the health benefits of catechins such as epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), and epicatechin (EC).

Green tea also contains 2% to 4% caffeine or about 10-80 milligrams per cup. (For reference, a cup of regular coffee contains 95 mg of caffeine, while 1 oz. of dark chocolate contains 23 mg.) Caffeine has also been the topic of many research studies regarding the health benefits of green tea.

Health Benefits of Green Tea: What the Research Really Shows

The research to date indicates that green tea is likely effective for:
  • Improving mental alertness. Because of the caffeine content, green tea and other caffeinated beverages can help maintain alertness and cognitive ability when used throughout the day.
  • Treating genital warts. An FDA prescription ointment that uses green tea extract heals genital and perianal warts in 24-60% of patients.
Research to date shows that green tea might be effective for:
  • Improving cholesterol levels. Green tea may help reduce elevated levels of LDL ("bad") cholesterol, total cholesterol, and triglycerides while increasing HDL ("healthy") cholesterol in the blood. However, more clinical studies are needed in this area.
  • Preventing low blood pressure upon standing and after eating (in the elderly population). This is likely due to the caffeine content of green tea.
  • Reducing the risk or preventing the onset of Parkinson's disease.This is also attributed to the caffeine content.
  • Preventing cancers of the bladder, esophagus, ovaries and pancreas. Most of these studies have been conducted on animals, but a few involved testing green tea extracts on people. More research is needed.
Currently, there is not enough evidence to say that green tea has the following health benefits:
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About The Author

Becky Hand Becky Hand
Becky is a registered and licensed dietitian with almost 20 years of experience. A certified health coach through the Cooper Institute with a master's degree in health education, she makes nutrition principles practical, easy-to-apply and fun. See all of Becky's articles.

Member Comments

  • What about Macha tea? - 1/8/2015 11:07:13 AM
  • So what's the verdict on things like flavored teas? For example, I like...Simply Balanced Organic Berry Hibiscus Tea... - 11/4/2014 11:11:28 AM
    I love green tea. I drink it because I love the taste. Pure and simple. - 5/4/2014 4:56:11 PM

  • I have started taking the supplement. I read that green tea extract increased the effectiveness of processes to increase collagen by 10 times over the light therapy process alone. I say this in response to the person who mentioned skin.

    My friend took it to get rid of fibroids after the doctor said surgery was the only option and it worked.

    Mine says decaffeinated and I am wondering if that changes the warning, other than the iron and folic acid. - 2/27/2014 4:05:32 PM
    Does Starbucks Iced green tea have the health benefits attrributed to green tea. or is this something else - 2/21/2014 6:13:43 PM
  • AMC8909
    I love green tea. Although this article says it's ok to drink while pregnant, I have read that you shouldn't due to the fact it depletes your folic acid, which can cause birth defects.

    P.S. If you drink a lot of tea, check out www.bulkherbstore
    .com. They have some really great ones and their website lists the health benifits of all of them. I love their site. - 1/12/2014 2:45:11 PM
    I've been drinking Original wuyi for 2 days and I already see a noticeably improvement in my skin. My cystic acne spots have dried up and my face looks less red after just 2 days. I definitely recommend drinking green tea as I think cystic acne has more to do with diet than hormones, I no longer get whiteheads that used to plague me. I recently did a complete diet overall and have cut out dairy and caffeine completely. After 2 days I saw the improvements already. - 11/3/2013 7:16:04 AM
    My hubby loves green tea; I like mine black. - 4/14/2013 5:18:19 AM
  • I've been told that it's best to use boiled water that has been given time to cool slightly. Freshly boiled water can burn the leaves and causes the tea to become bitter. This is very likely why I've never been a fan. I've been doing it wrong all these years. Should give it another go and use that jasmine green that i have sitting in the tea cupboard. - 3/18/2013 11:50:54 PM
  • Love green tea! Used to drink it constantly, but have found that with my hyperthyroid, even the slightest bit of caffeine throws me way off track! It's really strange and makes me sad :( But I guess since green tea isn't as good for me as I though, oh well.... - 3/5/2013 9:26:37 PM
  • Green tea is contraindicated with people who take blood thinners like Coumadin. Thought I would throw that out. - 2/19/2013 11:12:09 PM
  • This is my favorite tea. - 1/26/2013 5:35:48 PM
  • THIS IS MY PREFERS TEA. GREAT - 1/26/2013 5:33:23 PM
  • PS... for those that don't like the flavor, you can cook with it. Therapeutic levels (from Japanese use) are 10 cups a day! That's why I use the ground leaf form - in baked goods, even on meat if you don't like the flavor). But I do like the flavor. And I like even more having no JOINT pain (I've been in a car wreck and a horse wreck - no joint pain at all!) - 1/24/2013 1:46:04 PM
  • I use a ground leaf green tea (about a tsp a day, equivalent of about 10 cups) and found that it directly correlates to relieving joint pain. I started when I had a cancer dx - took this and other measures for 3 months before - interestingly, no cancer found after the hysterectomy. - 1/24/2013 1:44:06 PM

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