By Alyse Levine
Concept
The media has exhaustively publicized the numerous ways drinking tea is good for you: from fighting certain cancers, to decreasing the risk of heart disease and Alzheimer's disease, to controlling cholesterol and even reducing tooth decay! Although most people are aware of tea's health benefits, they are not aware of which teas are the most beneficial. So, from a health perspective, are all teas created equal?
Nutritional Facts and Figures
What are the purported health benefits of consuming tea?
Before we begin, note that here we are talking about tea from the tea plant, Camellia sinensis, and not herbal teas, which are really derived from the flowers, leaves, seeds, bark, or roots of certain plants but contain no actual “real” tea (herbal teas do have purported health benefits, but they are beyond the scope of this bite).
Studies have shown that tea may promote good health in the following ways:
*Heart Health: The polyphenols (antioxidants) found in tea are very effective in preventing cholesterol from oxidizing and damaging blood vessels. Green tea has been shown to improve the health of the delicate cells lining the blood vessels, which helps lower one's risk of heart disease (1).
*Cancer Prevention: The polyphenols (catechins in particular) in tea may help prevent or decrease the growth and spread of certain cancers. They scavenge oxidants before cell injuries occur, reduce the incidence and size of chemically induced tumors, and inhibit the growth of tumor cells. In studies of liver, skin, and stomach cancer, chemically induced tumors were shown to decrease in size in mice that were fed green and black tea (2,3).
*Skin Protector: Not only has tea been shown to be effective in decreasing cancer risk when consumed orally, but it may also be beneficial when applied superficially to the skin (4). Some research has shown that when green tea is applied to sunburned skin it decreases the development of cancerous skin tumors. This evidence has led many cosmetics companies to start adding green tea to their skin care products.
*Alzheimer's Disease Arsenal: Both green and black teas have been shown to hinder the activity of two enzymes in the brain associated with Alzheimer's disease. Although tea consumption cannot cure Alzheimer's, it may be another part of the puzzle in treating or slowing down the development of the disease (5).
*Good for Teeth: Compounds in tea protect teeth by increasing the acid resistance of tooth enamel and acting as antibiotics that kill off dangerous, decay-promoting bacteria (6). Tea also contains fluoride, which is essential for keeping teeth strong and healthy.
Which tea varieties provide the above health benefits?
All "real" teas, which include green, black, and oolong tea varieties, are beneficial to your health. As mentioned above, these teas are all derived from the same tea plant, Camellia sinensis, and contain numerous healthful compounds including polyphenols (particularly catechins), tocopherol, vitamin C, as well as other antioxidants. The polyphenols are believed to be responsible for most of tea's role in promoting good health. Although black, green and oolong teas have different polyphenol compositions due to processing differences, they all have been shown to provide the above health benefits.
The differences between the teas are depicted below. As you can see, the main difference between the "real" teas is simply in how the leaves are processed.
Green Teas (Japanese, Chinese, Gunpowder, etc...)
Green teas are the freshest and least processed because they are not at all fermented. Of all "real" teas, green tea has the lightest and most subtle taste.
Black Teas (Darjeeling, Earl Grey, China Black, Jasmine, etc...)
Black tea is simply green tea that has been fermented for around 6 hours. Fermentation turns the green leaves black and alters the polyphenol content, though it is still very high in antioxidants. Black teas have the strongest taste.
Oolong Teas
These teas are made from green teas that are briefly fermented. Therefore, they are a compromise between black and green tea in both taste and color.
To Get the Most Out of Tea:
*To get the benefits claimed above, opt for a "real" tea variety (green, black, or oolong), as opposed to an herbal tea
*Steep tea for about 3 minutes; this time allotment enables the health promoting compounds to be released; steeping for much longer turns the tea bitter and releases too much tannin, which can irritate the digestive tract, cause constipation, and decrease iron absorption.
*Hot or Cold? Go for what you like! Bottled teas, iced tea, and teas made from mixes are also all rich in polyphenols. However, keep iced tea fresh, the polyphenol content starts to deteriorate after a few days.
Note on Caffeine:
If you are worried about the caffeine content of tea, opt for the decaffeinated varieties...they provide the same health benefits without keeping you up all night.
Alyse's Advice
The next time you reach for a warm, soothing cup of tea, opt for either green, black or oolong varieties, and steep for about 3 minutes. If you prefer the iced kind, follow the same guidelines but make sure to finish it within a few days before the antioxidant content starts to decline. A few cups of tea a day may help keep the heart doctor and dentist away, as well as cancer and Alzheimer's disease at bay.
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References
1. The acute effect of green tea consumption on endothelial function in healthy individuals. Alexopoulos N, Vlachopoulos C, Aznaouridis K, Baou K, Vasiliadou C, Pietri P, Xaplanteris P, Stefanadi E, Stefanadis C. Eur J Cardiovasc Prev Rehabil. 2008 Jun;15(3):300-5.
2. Dufresne CJ, Farnworth ER. A review of latest research findings on the health promotion properties of tea. J. Nutri Biochem 2001; 12(7):404–421.
3. Hakim IA, Harris RB. Joint effects of citrus peel use and black tea intake on risk of squamous cell carcinoma of the skin. BMC Derm 2001; 1(3).
4. Non-sunscreen photoprotection: antioxidants add value to a sunscreen. Matsui MS, Hsia A, Miller JD, Hanneman K, Scull H, Cooper KD, Baron E. J Investig Dermatol Symp Proc. 2009 Aug;14(1):56-9.
5. Naturally occurring phytochemicals for the prevention of Alzheimer's disease.
Kim J, Lee HJ, Lee KW. J Neurochem. 2009 Dec 26. [Epub ahead of print]
6. Association between green tea consumption and tooth loss: cross-sectional results from the Ohsaki Cohort 2006 Study. Koyama Y, Kuriyama S, Aida J, Sone T, Nakaya N, Ohmori-Matsuda K, Hozawa A, Tsuji I. Prev Med. 2010 Apr;50(4):173-9. Epub 2010 Jan 25.
