10 Evidence-Based Benefits of Green Tea for Health

What is Green Tea?

Green tea is a type of tea made solely from the leaves of the Camellia sinensis plant. It is different from black and oolong teas in that it skips the "withering" and "oxidation" steps during processing.

After picking, green tea leaves are quickly heated by steaming or pan-frying to inactivate oxidation enzymes and retain their green color. The leaves are then rolled and dried before being packaged.

Compared to other teas, green tea is minimally processed which allows it to maintain higher amounts of antioxidants and polyphenols that are often degraded during black tea production.

Origins and History

The origins of green tea can be traced back to ancient China over 4,000 years ago. According to legend, green tea was first brewed accidentally when tea leaves fell into boiling water.

Green tea consumption spread throughout Asia where it was mainly used for medicinal purposes. It remains a staple beverage in many Asian countries today.

Green tea only recently gained popularity in the West during the early 2000s mainly for its purported health benefits, unique flavor and variety of blends.

How Green Tea is Produced

Green tea production consists of five stages:

1. Plucking: The top leaves and leaf buds are picked by hand.
2. Withering: Leaves are laid out to dry to remove excess moisture.
3. Steaming or Pan-frying: Stops oxidation leaving leaves green.
4. Rolling and Shaping: Gives leaves their final curled appearance.
5. Drying: Leaves are dried and then packaged for sale.

Types of Green Tea

There are various types of green tea depending on growing conditions, harvesting techniques and processing. Some main varieties include:

• Sencha: Most common green tea in Japan. Full-bodied taste.
• Matcha: Powdered green tea used in tea ceremonies. Rich flavor.
• Gunpowder: Chinese green tea rolled into pellet shapes. Strong and bold.
• Hōjicha: Japanese green tea roasted over charcoal. Lower in caffeine.
• Genmaicha: Japanese green tea with toasted rice. Nutty flavor.

Nutrition Facts of Green Tea

Green tea is derived from the Camellia sinensis plant which contains a range of essential nutrients and beneficial plant compounds.

Antioxidants

Green tea is rich in polyphenol antioxidants including catechins, the most abundant being EGCG (epigallocatechin gallate).

EGCG and other catechins have potent antioxidant activities that may protect cells from damage caused by free radicals.

Amino Acids

Green tea contains small amounts of amino acids such as theanine, tyrosine, and leucine. These may work synergistically with caffeine to enhance alertness and cognition.

Vitamins and Minerals

Green tea also provides an array of B vitamins, vitamin C, zinc, magnesium, calcium and iron in modest amounts.

Caffeine

All types of tea plant leaves naturally contain caffeine, although in smaller amounts compared to coffee. Green tea has about 25-50mg caffeine per 8 ounce cup.

10 Evidence-Based Benefits of Green Tea

Research shows drinking green tea may provide a variety of health benefits. Here are 10 evidence-based ways green tea may benefit health.

1. Rich in Antioxidants

Green tea is loaded with polyphenol antioxidants including catechins. The most abundant and potent catechin in green tea is EGCG.

Studies show EGCG and other green tea antioxidants have anti-inflammatory effects that may help prevent chronic diseases like heart disease, cancer and diabetes.

For example, Japanese people who drink 5+ cups of green tea daily were significantly less likely to die from heart disease according to a massive population-based study.

2. May Boost Brain Function

The combination of caffeine and L-theanine in green tea may enhance brain function by improving mood, attention and memory.

Human trials show green tea can increase blood flow and activation in parts of the brain linked to cognition and memory.

Green tea also contains the amino acid theanine which can cross the blood-brain barrier. Theanine has been shown to increase levels of serotonin, dopamine and GABA in the brain which may boost mood.

3. May Help Burn Fat

Green tea contains caffeine and EGCG, both of which may aid fat loss. The caffeine provides a mild metabolic boost while the EGCG boosts metabolism and fat burning.

In one study, healthy men who took green tea extract before exercise burned 17% more fat than the control group.

Another study had overweight women take 870mg of green tea catechins per day for 12 weeks and reduce body fat by 3.6% compared to placebo group.

4. Anti-Aging Properties

The powerful antioxidants in green tea called catechins can help fight cell damage caused by free radicals. This may slow down signs of aging.

Green tea applied topically has been shown to reduce sun damage and protect skin from UV radiation according to animal studies.

Drinking green tea may also help preserve collagen, the protein in connective tissues that keeps skin strong and elastic.

5. May Lower 'Bad' LDL Cholesterol

Green tea catechins, especially EGCG, have been shown to significantly reduce blood levels of LDL or "bad" cholesterol.

In a comprehensive review of 11 studies with over 800 people, green tea reduced total and LDL cholesterol by 7.2mg/dL and 2.2mg/dL, respectively.

Green tea may also prevent LDL particles from oxidizing, another factor influencing heart disease risk.

6. Helps Lower Blood Pressure

Regularly drinking green tea may help keep blood pressure levels in a healthy range. One study had people drink 3 cups per day for 12 weeks and significantly lower both systolic and diastolic blood pressure.

Green tea improves blood vessel function and can help blood flow better throughout the body. The modest blood pressure lowering effect may reduce the risk of stroke and heart disease.

7. Anti-Cancer Properties

Many test tube and animal studies show green tea polyphenols like EGCG have potent anti-cancer properties.

Researchers believe these compounds may suppress tumor growth and lower cancer risk. However, human trials testing green tea's direct cancer-fighting effects are limited thus far.

But population studies link drinking green tea, mainly in Asian countries, to significantly reduced risk of developing prostate, breast and colorectal cancers.

8. Helps Maintain Bone Density

Green tea may support bone health as we age. Older women at high risk for fractures who drank over 4 cups of green tea daily had better bone mineral density measurements compared to those who didn't drink tea.

The flavonoids in green tea may promote bone growth in cells and strengthen bones by reducing oxidative stress bone cells are often subject to.

9. Supports Oral Health

Green tea has natural antibacterial compounds like catechins that inhibit growth of many oral bacteria linked to plaque formation and cavities.

Regularly drinking green tea has been shown to reduce periodontal disease, tooth loss and bad breath. Green tea mouthwash may also combat gingivitis.

The antioxidants in green tea also have an anti-inflammatory effect that may help relieve swelling in gums.

10. Aids Digestion

Animal studies indicate green tea may provide digestive and gut health benefits. EGCG has been shown to inhibit inflammation in gastrointestinal cells.

Green tea also contains other polyphenols that seem to support healthy gut bacteria. A daily cup of green tea significantly increased bifidobacteria levels in one human study.

More research is needed, but green tea may aid digestion by promoting healthy gut flora and reducing inflammation.

How to Prepare Green Tea

To brew green tea, avoid boiling water which can diminish its antioxidant content. Here is a simple method:

1. Heat water to 160–180 ̊F (71–82 ̊C). Lower temperatures maximize polyphenol content.
2. For one cup, use 1 teaspoon leaves (2 grams) or 1 tea bag.
3. Steep green tea leaves for 1-3 minutes. Longer steeping boosts polyphenols but increases bitterness.
4. Drink green tea plain or add fresh lemon juice or honey for flavor. Avoid milk as proteins can bind to and neutralize polyphenols.

Matcha Green Tea

Matcha is a powdered green tea used in traditional Japanese tea ceremonies. To make matcha:

• Sift 1-2 teaspoon matcha powder into a cup.
• Add 2 ounces hot water (160–180 ̊F) and whisk vigorously with a tea whisk until frothy.
• Drink immediately for best flavor and health benefits.

Potential Side Effects

Enjoyed regularly in moderation, green tea is highly safe for most people and associated with minimal side effects.

Caffeine Sensitivity

Green tea contains less caffeine than coffee, but those sensitive may still experience side effects like headaches, anxiety and trouble sleeping from the 25-50mg of caffeine per 8oz cup.

Upset Stomach

Drinking large amounts may cause nausea and upset stomach due to caffeine and tannins. Start with small servings and gradually increase intake to reduce risk.

Iron Deficiency

Compounds in green tea can bind iron in foods, making it harder to absorb. Those at risk of iron deficiency should avoid drinking green tea with meals.

Pregnant women, infants, children and those with kidney or liver problems should consult a doctor before regularly consuming green tea.

The Bottom Line

Green tea and green tea extract supplements contain many science-backed nutrients, antioxidants and plant compounds that benefit health.

Regularly drinking green tea may enhance brain function, promote fat loss, reduce risk of heart disease and many types of cancer, bolster bone density and support oral health.

Green tea has a more delicate flavor than black tea and is free of added dairy and sweeteners. Drink 2-3 cups per day for the most benefits.

Supplements can provide higher EGCG doses, but plain green tea has a wholesome blend of naturally occurring nutrients and antioxidants.

Green tea is very safe when consumed in moderation. Brew plain non-caffeinated varieties at night if caffeine affects your sleep.

Green tea is a simple daily health habit backed by thousands of years of tradition and decades of scientific research.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.