Decaffeinated Green Tea Warnings!
Natural Versus CO2

For a tea to be legally labeled "decaffeinated" in the United States, 98% of the caffeine must be removed. This means one cup should contain less than 5 milligram of caffeine or 0.4% in dry weight. For caffeine sensitive individuals, drinking decaffeinated tea may seem an ideal way to enjoy tea health benefits without its side effects.

Unfortunately, things do not quite work out this way. The decaffeination process also removes one third to half of the antioxidants found in green tea.

A 2003 study conducted by the UCLA Center for Human Nutrition found that decaffeinated tea contains only a third of the catechins found in regular tea. Regular tea contains 21 to 103 milligrams of catechins per gram. Decaf contains only 5 to 50 milligrams.

Another separate study by the US Department of Agriculture reported similar findings. According to this study, decaffeinated green tea contains only 56 milligrams of catechins per gram, less than half of the catechins found in a regular tea.

This is bad news. Catechins are the most active antioxidants in green tea. They contribute greatly to its flavors. No wonder many complain that decaf tastes awful.

Where have the catechins gone? The answers lie in the processing. Decaffeinated green tea is usually made using two chemical solvents: ethyl acetate and carbon dioxide.

The most commonly available decaffeinated green tea is "naturally decaffeinated". It is made using a chemical solvent called ethyl acetate.

During this process, tea leaves are soaked in water to release caffeine and other tea compounds. This is followed by separating the tea leaves from the water, and bringing the water into contact with ethyl acetate to absorb the caffeine. Finally, tea leaves are re-immersed in the water to reabsorb the lost tea nutrients.

Now, here is a problem. Tea leaves are returned to the water that contains traces of ethyl acetate. At high doses, ethyl acetate is known to cause problems to the liver, and to the respiratory and nervous systems.

This process is technically known as supercritical fluid extraction. Tea leaves are soaked in a carbon dioxide solution to release caffeine.

This is followed by separating the tea leaves from the solution, and filtering out the caffeine using active carbon or charcoal. Finally tea leaves are re-immersed into the solution to reabsorb the lost tea nutrients.

It is widely believed that the CO2 decaffeination process preserves as much as 95% of the tea compounds. Unlike ethyl acetate, there is no concern about residue.

Unfortunately, CO2 decaffeinated green tea is not widely available. This may be due to the high cost of processing and light taste offer poor value for the money.

(Why spend lots of money on a CO2 tea when you can buy a high grade tea that has been prized over the centuries for its soothing and mood enhancing benefits?)

Unlike black tea, green tea is unoxidised. A process - called fixation - applies heat to arrest the oxidation, or fermentation. The best decaffeination is done before the fixation process.

Fresh tea leaves are soaked in hot water. Since caffeine is quick to dissolve in water, this process removes caffeine but leaves most of the nutrients intact. A 2007 study published in the Food Chemistry Journal found that as much as 95% of catechins are preserved in the process.

The decaffeinated leaves can then be pan-fried or baked to add flavor. To me, this is the most promising decaffeination method, albeit one for the future!

If you want a product that has lots of antioxidants and near-zero caffeine, then you may find a tea supplement such as Teavigo suitable.

The disadvantage of such a caffeine-free product is that there is no evidence that it promotes weight loss. You are also missing out on the full spectrum of tea nutrition (such as the other catechins and theanine).

Teavigo EGCG Extract - Best Green Tea Supplement?

Ever wonder why high grade green tea, which contains the highest level of caffeine, is more soothing to drink than lower grade tea? The answer is theanine.

Scientific studies performed using electroencephalography discovered that theanine decaffeinates tea naturally. If about 8 times more (theanine?) is given (ingested?) than caffeine, the effects of caffeine are completely blunted.

Theanine is found at the highest levels in young tea buds, harvested in early spring. These highest grade teas can be purchased from reputable tea vendors selling Chinese Dragon Well or the Japanese Gyokuro.

Now, this is natural decaffeination at its best.

How does the nutrition analysis of regular green tea compare with decaffeinated green tea? The World's Healthiest Foods. http://whfoods.org/genpage.php?tname=dailytip&dbid=200.

US Department of Agriculture. USDA Database for the Flavanoid Content of Selected Foods Release 2.1. http://www.nal.usda.gov/fnic/foodcomp/Data/Flav/Flav02-1.pdf

Henning SM, Fajardo-Lira C, Lee HW, Youssefian AA, Go VL, Heber D. Catechin content of 18 teas and a green tea extract supplement. Nutr Cancer. 2003;45(2):226-35. UCLA Center for Human Nutrition, School of Medicine, Warren Hall 14-166, 900 Veteran Avenue, Los Angeles, CA 90095, USA. shenning@mednet.ucla.edu.

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