Love the Benefits of Green Tea

Tea is the world’s most consumed beverage after water and throughout the world tea offers insight into the customs of different cultures. But more than this, tea, and green tea in particular, has been widely studied for its health benefits for some of the most common chronic illnesses.

It’s speculated that the first cup of tea was made in China around 2737 BC, however, tea did not gain popularity until the 15th century. All tea, whether black, oolong or green, come from the same evergreen tree, camellia sinensis. But how the tree is grown and then prepared tells the story of their differences. After harvest, the leaves are processed based on how much oxidation—or ‘fermentation’—they will undergo. Black teas are fully oxidized, oolong teas partially oxidized, and green teas minimally oxidized.

To produce green tea, leaves are quickly steamed or pan-fired to stop enzymatic oxidation, preserving their green color and delicate flavor. The steaming process allows the leaves to remain a green color by blocking the enzyme which would otherwise break down the color. Once steamed, it is then rolled and dried. The flavor and nutritional value of green tea can also vary in where it’s grown. Matcha and gyokuro are both shade grown while sencha and bancha are both full sun grown. The shade grown varieties have preserved higher theanine levels and caffeine - discussed below. Matcha itself refers to the powdered green tea leaves which have become so popular recently that - at the time of writing - there's a global shortage. 

Health Benefits 

The composition of green tea consists of polyphenols, caffeine, minerals, and trace amounts of vitamins, amino acids, and carbohydrates. Trace minerals in green tea include magnesium, chromium, manganese, calcium, copper, zinc, iron and selenium. The polyphenols fall under the classification of phytonutrients, or plant chemicals. Polyphenols are further broken down in green tea under the classification of catechins, which are known for having potent antioxidants. The four main types of catechins found in green tea are epicatechin, epigallocatechin, epicatechin-3-gallate, and EGCG (epigallocatechin gallate). As with any phytonutrient, differences in variety, origin, and growing conditions can all influence the quantity and quality of these catechins. They are found in higher amounts in green tea though compared with oolong or black teas due to the preparation, i.e. they are not oxidized. It is also the catechins that can decrease the absorption of iron.

From available data, green tea catechins have antioxidant, anti-inflammatory, antimicrobial, antiviral, and antitumor properties. This translates to many potential benefits for prevention and management of chronic health conditions including cancer. Most of this evidence comes from cell and animal models; human research supports potential roles in cardiometabolic health, cognitive performance, and cancer prevention, but more research is needed.

The effects of green tea have been studied in certain cancers including breast cancer, prostate cancer, lung cancer (cell studies), bladder cancer, colorectal cancer, liver cancer, stomach cancer and melanoma. There is still not sufficient evidence to determine the effects of green tea on cancer risk. 

Caffeine, while often referenced for its ability to keep us alert or awake in some cases, also plays a role as an antioxidant. Factors that contribute to caffeine content include variety of the tea leaf and age of the tea. Caffeine content varies from about 10–20 mg per 8 oz in roasted teas such as Hōjicha to 60–70 mg in powdered Matcha. Shade-grown teas like Gyokuro fall toward the higher end because shading increases caffeine and theanine accumulation.

Another compound found in green tea is L-theanine, an amino acid. L-theanine is purported to have a calming effect and is often used in stress supplements. Additionally, this compound is attributed with giving green tea part of its umami flavor. Umami — a Japanese word meaning ‘pleasant savory taste’ — is considered the fifth basic taste alongside sweet, salty, sour, and bitter. Theanine contributes to this creamy, broth-like flavor while also supporting calm alertness by promoting alpha-wave brain activity. Clinical trials have shown the benefits of L-theanine on neurotransmitters for sleep, stress, focus, memory and mood. It has been studied for its effect on brain alpha wave activity - a marker for relaxation, and for its positive impact on sleep quality. 

It is worth noting that catechins, caffeine and L-theanine are all currently being investigated for their benefits on cognitive function. While green tea’s health benefits are well studied, the dose, frequency, and preparation needed to reproduce laboratory findings in daily life are still being clarified.

Types of green tea

The research on green tea continues to look very promising but even the most convincing evidence has to pass the test of taste. A few key tips before you pass judgement or if you have been drinking just one type. 

Tea, like any plant foods, are best when consumed fresh. Do not let it sit in the cupboard for months and expect the same taste and quality. This also goes for grains, legumes, nuts, seeds which do not always show their age like fresh vegetables and fruit. 

Brewing

How tea tastes can depend on how it is brewed. This is a general rule of thumb for green teas but there will be many variations based on more specific varieties.

1. Start with cold water and heat to about 160–175°F (70–80°C) — just below boiling.

2. Pour the water over the tea leaves (or tea bag). Steep for 1–3 minutes.

3. After a minute, try tasting every 30 seconds to find the perfect steeping time. Smaller leaves infuse faster than larger ones. Oversteeping can produce bitterness as catechins and caffeine continue to extract.

4. Remove the tea leaves when the taste is where you want it and enjoy!

If you’re ready to explore more about green tea, use our chart below for some ideas. Most green teas are produced in China and Japan but can also come from Korea, Indonesia, Sri Lanka, Vietnam, Russia, Turkey and Iran. 

References:

• Prasanth M., et al. A Review of the Role of Green Tea (Camellia sinensis) in Antiphotoaging, Stress Resistance, Neuroprotection, and Autophagy. Nutrients. 2019 Feb 23;11(2):474. doi: 10.3390/nu11020474

  
  

• Radeva-Illieva M. et al. Green Tea: Current knowledge and issues. Foods 2025, 14(5), 745; https://doi.org/10.3390/foods14050745

  
  

• Musial C., et al Beneficial Properties of Green Tea Catechins. Int J Mol Sci. 2020 Mar 4;21(5):1744. doi: 10.3390/ijms21051744