Are There Health Benefits to Drinking Green Tea?

Green tea has been a popular drink as well as a traditional medicine in China and Japan for thousands of years. Early in the 17th century, it was introduced to consumers in Europe who rapidly came to embrace the beverage. In 18th century England, green tea was so valuable and popular that it was frequently smuggled in to avoid taxes.

These days there’s no need to resort to smuggling. Green tea is widely available across the globe. Dozens of brands of bagged green tea can be found on store shelves, blended from a variety of green tea. There are flavored and sweetened varieties as well as green tea powders and loose-leaf tea. Whatever way you want to consume green tea, there’s probably a product already on the market.

Green tea is often consumed for reasons other than for its health benefits, however, there’s actually quite a lot happening in a cup of green tea, and it’s worth getting to the bottom of.

Nutrition Information

While there are many compounds, nutrients, vitamins, and minerals in green tea leaves, those elements are extremely diluted in a single cup of tea. Once steeped, the resulting green tea beverage is almost entirely water.

The nutrients found in 8 fluid ounces, or roughly one mug of green tea include:

  • Calories: 0
  • Protein: 0 grams
  • Fat: 0 grams
  • Carbohydrates: 0 grams
  • Fiber: 0 grams
  • Sugar: 0 grams

Similarly, the vitamins and minerals found in steeped green tea are also very minimal. A few that can be found in measurable quantities include:

Green tea is also relatively high in caffeine, having about one-fourth the amount of coffee. Finally, it packs a potent punch of polyphenols, a type of antioxidants.

Potential Health Benefits of Green Tea

Many health benefit claims have been made about green tea for centuries. Traditionally, in China and India, green tea was a medicine for controlling bleeding, aiding digestion, and regulating body temperature. In modern times, research has been able to demonstrate some of its health benefits more solidly than others.

Heart Health

One large study in Japan followed 40,000 adult participants over 11 years, and found that daily green tea consumption was linked to lower risk of death from cardiovascular disease. In particular, the study was examining the link between the polyphenols (antioxidants) in green tea and cardiovascular diseases. The minimum daily consumption required to see this benefit was five cups per day.

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Stroke Prevention

Another large Japanese study, this one following more than 82,000 participants over 13 years, found that higher consumption rates of green tea were associated with reduced risk of stroke. Participants who drank four cups per day or more saw the highest benefit.

Genital Wart Treatment

The U.S. Food and Drug Administration has approved a topical green tea extract treatment to treat breakouts of genital warts. This ointment is available by prescription only and is estimated to be effective for between 24% to 60% of patients.

Potential Risks of Green Tea

Green tea, when drunk at a moderate rate of 8 cups per day or less, is considered safe for most adults. However, there are risks posed by consuming green tea in high concentrations, especially as an extract.

Liver Problems

Rare cases of green tea extract causing liver problems have been documented. While the research is limited, people with existing liver problems are generally advised to avoid green tea extracts. People who experience symptoms such as abdominal pain, dark urine, or jaundice while taking green tea extract should discontinue use and consult a physician.

Diabetes Complications

As a caffeine-rich drink, green tea may pose a risk to people with diabetes. Caffeine has been shown to potentially raise blood sugar of people with type-2 diabetes. 

WebMD Medical Reference Reviewed by Dan Brennan, MD on September 29, 2020

Sources

SOURCES:

European Journal of Clinical Nutrition: “Liver-Related Safety Assessment of Green Tea Extracts in Humans.”

ESHA Research, Inc., Salem, Oregon: “Tea, green, bags, Lipton”

JAMA: “Green tea consumption and mortality due to cardiovascular disease, cancer, and all causes in Japan: the Ohsaki study.”

Life Sciences: “Tea polyphenols for health promotion”

National Center for Complementary and Integrative Health: “Green Tea”

Pharmacognosy Reviews: Green tea (Camellia Sinensis): “Chemistry, Traditional, Medicinal uses and its Pharmacological activities- a review.”

Stroke: “The Impact of Green Tea and Coffee Consumption on the Reduced Risk of Stroke Incidence in Japanese Population.”

University of Minnesota: Tea Consumers, Tea Trade, and Colonial Cultivation

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