Scientists analyzed eye tissue from rats that drank green tea. They found that eye tissues such as the lens and retina had absorbed green tea catechins.
According to NutraIngredients:
“The [study’s] authors said that oxidative stress causes biological disturbances such as DNA damage and activation of proteolytic enzymes that can lead to tissue cell damage or dysfunction and eventually many ophthalmic diseases.”
Antioxidants are known to have a wide variety of health benefits, and now researchers have linked them to eye health as well, by evaluating the antioxidant content distributed in the eyes following the consumption of green tea.
They found that the catechins found in green tea were absorbed into various parts of the eyes anywhere from 30 minutes to 12 hours after rats were given the tea.
Catechins, a class of polyphenolic antioxidants, have been reported to have various physiological and pharmacological properties, and can be divided into several sub types, including:
- Epigallocatechin gallate (EGCG)
- Epigallocatechin (EGC)
- Epicatechin gallate (ECG)
- Epicatechin (EC)
- Gallocatechin gallate (GCG)
In this study, they were able to discern the types and amounts of green tea catechins absorbed by the various parts of the eyes.
The retina absorbed the highest levels of gallocatechin, while the aqueous humor (the fluid in the chambers of your eye) soaked up the highest amounts of epigallocatechin (EGCG).
The Many Health Benefits of Green Tea Antioxidants
There are certain compounds and nutrients that seem to have near limitless health potential, and catechins are part of that pack. Fortunately, green tea is an excellent source of these antioxidants, making them easily available to anyone with the good sense to pay attention.
Aside from potentially saving your eyesight, green tea catechins have also been found to:
- Protect your heart and cardiovascular system
- Hinder progression of cancer
- Ease inflammation and pain associated with rheumatoid arthritis (RA)
- Reduce your risk of Alzheimer’s and autoimmune diseases such as Sjogren's Syndrome
- Promote healthy gums
- Improve digestion
Epigallocatechin gallate (EGCG), specifically, is one of the most powerful antioxidants known, and the health benefits of EGCG include the prevention of:
- High blood lipid
- Cerebral thrombus
- Heart attack and stroke
Several studies have also found that EGCG can improve exercise performance, increase fat oxidation, and may help prevent obesity, as it’s known to have a regulatory effect on fat metabolism.
Selecting a High Quality Green Tea
The polyphenols in green tea may constitute up to 30 percent of the dry leaf weight, so, when you drink a cup of green tea, you're drinking a fairly potent solution of healthy tea polyphenols. Green tea is the least processed kind of tea, so it also contains the highest amounts of EGCG of all tea varieties.
Other than water, I believe high-quality green tea is one of the most beneficial beverages you can consume.
But there are quality differences here as well.
Many green teas have been oxidized, and this process may take away many of its valuable properties. The easiest sign to look for when evaluating a green tea’s quality is its color: if your green tea is brown rather than green, it’s likely been oxidized.
My personal favorite is matcha green tea because it contains the entire ground tea leaf, and can contain over 100 times the EGCG provided from regular brewed green tea.
If you’re not familiar with tea you may have never heard of matcha tea. Rather than being steeped and strained like typical tea, matcha tea is made of tea leaves ground into a powder, and you mix the powder right into water.
The matcha tea is a vibrant bright green, and is far less processed and of much higher quality than most other green teas, so you also avoid the risk of ingesting high levels of fluoride, lead, and aluminum, which can be found in inferior teas of all kinds, including green teas.
What’s a Healthy Amount of Tea Each Day?
There’s no clear-cut evidence of exactly how much is best, but it’s a general misconception that it would take pot upon pot of green tea to add up to any significant benefits. In reality, much of the research on green tea has been based on about three cups daily.
One cup of green tea will provide you with 20-35 mg of EGCG, so three in a day will supply you with about 60-105 mg. (The actual amount will depend on the quality of your tea.)
Since green tea is the number one source of EGCG, my advice is to simply add a few cups of green tea to your day if you enjoy it. As always, listen to your body. If green tea doesn’t appeal to you, then it’s probably not the best thing for you.
Another tea that is shock-full of beneficial antioxidants is the Indian tulsi tea, which is another delicious, healthy option.