By Amanda Lovett-Jones RH (AHG)
The origins of tea
Tea is the most commonly consumed beverage in the world second only to water. The total annual sales exceeds $43 billion globally, and more than $11 billion of that relates to sale of green tea. (SNAP).
It is beloved worldwide for its slightly bitter and earthy taste, and for the feeling of rejuvenation and wellbeing experienced when drinking it.
Green tea comes from the same species of plant as black and white tea (Camilla sinensis). The different drying and fermentation methods allows for the differences in flavor, color and oxidation.
Green tea is treated with steam after harvest to deactivate the oxidative process (thus keeping their green and pale color and gentle flavor).
Oolong tea (a favorite in China) is partly oxidised (darker color than green tea and has a bolder/stronger flavor) and black tea (English breakfast, Earl grey etc) is fully oxidised (even darker color and boldest flavor).
It is widely accepted that green tea originated in China around 2700BC. China is the largest green tea producing country, producing approximately 480,000 tons of tea a year. In Japan, green tea is enjoyed daily and with every meal.
It also has a customary significance that transcends a simple hot drink. Green tea has an ethereal presence in several Asian cultures, where in Japan the tea ceremony represents purity, history, tranquillity, respect and harmony with much custom and preparation involved.
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Are matcha and green tea the same thing?
Matcha also comes from the Camellia sinensis plant, and is green yet they are grown and processed differently. Green tea is grown and harvested under the sun, while matcha tea is shade-grown in shorter periods (3 weeks) before it is harvested. Green tea, due to the sun exposure grows dull green with a brownish tone, and matcha tea grows a vibrant green color. The shade increases the chlorophyll levels in the leaves that turn matcha its bright color.
Green tea tends to come either loose or bagged. Matcha is a fine powder of ground green tea leaves. Each form of tea may have its own benefits for the body, but matcha tea is more commonly used in traditional tea ceremonies. People have their own preferences for taste and ways to consume.
Active compounds in green tea
Green tea has an abundance of pharmacologically active molecules, however polyphenols are the major active compounds found in teas.
Polyphenols are powerful antioxidants that exert their actions through various compounds. The catechins are the primary polyphenolic compounds in green tea, which include epigallocatechin-3-gallate (EGCG), epigallocatechin, epicatechin-3-gallate and epicatechin, gallocatechins and gallocatechin gallate.
EGCG is the predominant and most studied catechin in green tea. Beyond catechins, green tea contains flavanols, proteins, polysaccharides, fatty acids, vitamins including vitamin C, minerals, trace elements, amino acids, essential oils, chlorophyll and other plant substances and caffeine. Green tea has approximately a third of the caffeine of coffee beans. An 8-ounce (240 mL) serving of coffee provides 96 mg of caffeine, while the same amount of green tea provides 29mg of caffeine. Green tea also contains lutein and zeaxanthin, critical for macular and lens health. (SNAP)
Green tea is notably one of the most abundantly rich sources of antioxidants on the planet. The various chemical substances that make up green tea have antioxidant properties.
The most abundant of which make up 30% polyphenols by weight, and approximately 80% of these are the rich flavonols EGCG (Epigallocatechin gallate ).
EGCG is a major catechin, this is important for the eyes because catechins are readily absorbed by the tissues in the eye, unlike many other antioxidants.
What are antioxidants of all the substances found naturally in green tea, it’s the collective antioxidants that produce the most significant impact on health, and particularly, eye health. The role of antioxidants is to hunt for and neutralize free radicals.
Free radicals are molecules (atoms) that contain an unpaired electron. Due to this odd number of outer shell electrons, they are in a constant search to connect with another electron to rebalance and stabilize.
When mobilized they behave erratically, bumping into other atoms and creating ‘damage’ in other cells and DNA, thus - free radical damage, this creates what is called oxidative stress.
Oxidative stress is essentially an imbalance in the ratio between the production of free radicals in the body, and, the bodies ability to sweep up, counteract or neutralize their harmful effects by antioxidants.
The way the body neutralizes free radicals is by offering up one of its electrons to bind with the atom, which then creates an ‘off switch’ creating stabilization. The body produces its own antioxidants, but also ingests them through dietary sources to keep oxidative stress at bay. Oxidative stress causes inflammation and early cell death leading to premature aging, this especially can impact the eyes which are susceptible to age related degeneration.
What are the health benefits of green tea?
Green tea has received alot of attention from researchers, historians and health care professionals for its health promoting benefits. However, when you think of green tea you don’t automatically think about eye health.
Clear evidence has emerged that taking green tea daily fights oxidative stress and inflammation which in turn helps reduce cellular damage to the eyes from free radicals.
Green tea has been recognized for slowing the aging process - or more accurately, reducing free radicals to stop premature aging.
Elderly populations in China and Japan have been studied as the oldest living people in the world, and the one consistent practice of this demographic is drinking green tea on a daily basis. So what is abundantly clear is, green tea is very good for your health. So how can they impact eye health?
Eyes are one of the most fragile organs in the human body. They directly absorb light from the environment and are are highly vulnerable to light damage and oxidative stress from free radical damage. Oxidative stress directly impacts macular health and is linked to age-related degeneration so protecting the eyes using anti-inflammatory antioxidants makes alot of sense.
Rich source of lutein and zeaxanthin
Studies report that lutein and zeaxanthin are absorbers of blue light up to 400–500 nanometers, and thus protect the eye structures from dangerous doses of this radiation. The ability to absorb visible blue light is due to the structure of these compounds.(SNAP)
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Heart health
Green tea consumption has been associated with lower risk factors of heart disease. According to the National Institute of Health - Green tea is promoted for improving mental alertness, relieving digestive symptoms and headaches, and promoting weight loss. Green tea and its components, including epigallocatechin-3-gallate (EGCG), have been studied for their possible protective effects against heart disease and cancer, however more studies are needed. (SNAP)
Inflammation
Because of the incredible free radical neutralizing capacity of antioxidants, they protect cells, prevent illness, and help reduce inflammation. Studies suggest that EGCG from green tea has anti-inflammatory properties and acts as an anti-oxidant agent and therefore may have therapeutic potential for inflammatory conditions of the eye such as dry eye.(SNAP)(SNAP)
Metabolic health
Studies suggest that daily consumption of green tea promotes healthy metabolic function and can help maintain healthy weight. This is especially important for peopole with obesity as they are more likely to develop degenerative disease. Among different eye diseases, obesity has been linked with age-related cataract, glaucoma, maculopathy, and diabetic retinopathy. There has been steady research that supports an association between obesity and risk of age-related cataract. (SNAP)(SNAP)
Anti-aging
Due to its potent anti-oxidant profile, there have been many studies researching green tea for its ability to reduce oxidative stress and thus slow premature aging. As the eyes are so vulnerable to free radical damage from light, regular consumption of green tea can help to slow premature aging and thus have a protecting effect on the retina and lens. (SNAP)
Is green tea safe?
Green tea consumption as a beverage of 3-4 cups daily is GRAS (generally regarded as safe) by the Food and Drug Aministration. However, toxicity of catchins / EGCG may occur in large amounts. Additionally green tea contains caffeine, so excessive consumption runs the same toxicity risks. Reports state that consuming 338mg of green tea EGCG catechins is considered safe for adults. (SNAP)
Ways to consume green tea
There are several ways you can consume green tea to enjoy its health benefits, Steeping green tea leaves and consuming up to 4 cups daily to support eye and heart health and support overall wellbeing.
Green tea also comes in powder, as does matcha, you can use the powder to make hot beverages (teas, lattes), or add the powder to smoothies or food such as baked goods.
Traditional herbalists make green tea extract to be taken as a medicine for its health promoting properties. These tinctures are made using ethanol, or glycerin extraction methods to draw out and often standardize the potent polyphenol antioxidants. Tinctures can be taken internally to promote overall health.
There are many green tea dietary supplements out there, delivering green tea extract in pills, capsules, powder or liquid. It is important to read the label and ensure that the company is using methods to secure adequate and standardized amounts of polyphenols - especially catechins/EGCG.
You only have one set of eyes, and as we age, we are more susceptible to conditions that impact ocular health. Taking simple steps to prioritize your eye health can support them for years to come.
NOTE - if you are currently taking medication or, have liver disease please consult your healthcare professional before taking any extract or dietary supplement.
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Amanda Lovett-Jones is an Australian Naturopath, and practices in the US as a registered Herbalist and culinary medicine specialist. She is a freelance copywriter and compliance specialist within the dietary supplement industry. She owns a virtual natural therapies wellness clinic that targets and helps treat inflammation using complementary medicine and diet. She is currently studying in a PhD program (Herbology and Phytotherapy). She lives with her family and dog in Seattle.
