What is Green Tea Extract?
Tea (Camellia sinensis L.) is one of the most consumed beverages in the world. It can be classified into three main types: green tea, oolong tea and black tea.[1] [2]
There are two main varieties of C. sinensis: C. s. sinensis and C. s. assamica. The sinensis variety produces green, white, black and oolong tea and originates in China. The assamica variety is mainly found in India, Sri Lanka and some African countries, and usually produces black, oolong and pu’erh tea. [2]
C. s. sinensis leaves are harvested for green tea production (the tea we drink) when they are immature—light green in color. Mature leaves usually have a deeper green color than young leaves. Leaves with different maturation levels give diverse qualities of tea because their chemical compositions are different.
Tea can also be classified depending on the degree of fermentation during the processing. White tea and green tea are usually unfermented, oolong tea is semi-fermented, and black tea completely fermented. [1]
In general, the tips and the first two to three leaves are picked by hand for processing. This procedure is commonly repeated every one to two weeks. The green tea leaves are then rotated, dried and packed. [2]
Green tea leaves contain antioxidants including catechin, epicatechin, epigallocatechin, epicatechin gallate and apigallocatechin- 3- gallate. [4]
The seeds of green tea can also be used to produce tea oil and extract. The concentrated formula is used in a variety of supplements.
5 Interesting Facts About Green Tea and Green Tea Extract
- Green tea antioxidants may prevent against periodontal (gum) disease.
- Green tea extract can increase memory processing
- Green tea extract may be used in the cure of cutaneous leishmaniasis (a tropical parasitic skin infection, carried by a species of sand fly. Very rare in the U.S. but found in many other parts of the world, including Central and South America, Africa, southern Europe, the Middle East, and parts of Asia).
- A damp green tea bag placed over insect bites can reduce itching and swelling
- Green tea extract may reduce the growth of bacterial-related halitosis
In Which Foods Can We Find Green Tea Extract?
In the last decade, there has been a rising consumer interest in products supplemented with green tea extract. Green tea extract has been incorporated in various food products like bread, cookies, dehydrated apple, and various meat products. In some tests with fat spread—yellow fats including butter, margarine, and low-fat spreads—green tea extract showed antioxidant performance similar to conventional lab-produced antioxidants, and can be more cost-effective than other natural antioxidants. It could be ideal for both full-fat margarines as well as lower-fat products and products with more unsaturated fats, which are more sensitive to going rancid. [2]
And of course, it’s used in a number of dietary supplements for both its antioxidant properties and its caffeine content.
Health Benefits Of Green Tea Extract
Green tea extract has been shown to reduce blood pressure, chronic inflammation, and insulin resistance issues in obese, hypertensive (with high blood pressure) patients. Several studies reported other properties of green tea such as anti-arthritic, antibacterial, antioxidant, and neuro-protective effects. Developing areas of research include the effects of green tea catechins on cardiovascular and metabolic health. [5]
Green tea extract has been reported to prolong the shelf life of fresh-cut lettuce, fresh mutton and dry-fermented sausage at room temperature. [6]
Other possible benefits of green tea extract are preventive and/or therapeutic effects in relation to Parkinson’s and Alzheimer’s diseases, cancer, high cholesterol, and cardiovascular disease. Research is continuing.
Can Green Tea Extract Ever Be Bad For You?
Some dietary supplements containing green tea extract could be bad for you. Therefore, it is recommended to check for adverse effects of all the ingredients in multi-substance supplements before taking them. There don’t seem to be any adverse affects from drinking green tea made from leaves (up to 3 cups per day).
An article in the Journal of Ethnopharmacology reported that after taking capsules with green tea extracts (725 mg, 1 capsule/day) as a preventive therapy against breast cancer, a 63-year old woman patient presented acute hepatitis. [7]
Five Swedish patients reported a drug-induced liver injury associated with use of the weight-loss supplement Cuur® (herbal weight-loss supplement with 82 percent dry green tea extract). [8]
In April 2003, the manufacturer of Exolise® (a hydro-alcoholic extract of green tea), removed all their products from the market following thirteen cases of acute liver damage after its intake. [9]
Throughout the world, unlimited intake of “natural” products has been shown to be related with up to 10 percent frequency of liver toxicity, and green tea products are at the top of the list in order of frequency. [10]
The Takeaway
Even though green tea extract has multiple positive health effects, there are some negative effects from the consumption of dietary supplements containing them. It is better to drink green tea steeped from the leaves, and check with your health care professional before taking the extract as a supplement.
