What I have posted here is a bit controversial. A while back my sister was doing some research on green tea and she came across a study that alarmed her. Her husband was known to drink large quantities of green tea everyday so she continued her research and presented her finding. I was shocked and he immediately stopped drinking black and green tea all together! Like most nutritionists I have been recommending the use of green tea for years but had know idea that it was not good for some people.
I present this article, written by my sister, for your consideration. I have modified my recommendations and suggest that people with certain medical conditions, such as thyroid disfunction and osteoarthritis, may not benefit from this age-old beverage.
Sodium Fluoride in Black/Green Tea
By Lynn Daniluk
If you are unwilling to drink a glass of fluoridated water from a city tap, then you should think twice about drinking green or black tea.
According to the City of Ottawa website,
"In September 2009, the City of Ottawa reduced the target level of fluoride in drinking water to 0.70 mg/L in response to the new level recommended by Health Canada. These changes were made under the direction of the Medical Officer of Health." (1)
According to the calculations made by the Oregon State University's "Linus Pauling Institute Micronutrient Research Centre" (2) all tea has a higher level of sodium fluoride that the City of Ottawa's fluoridated drinking water. The levels per liter will depend on the length of time the tea is steeped but even a 5 minute brew will give you a higher level than Ottawa's City water. These calculations were made from tea that was brewed without fluoridated water so those levels would be compounded. It is important to note that the Linus Pauling Institute website does not have a problem with fluoridation as they feel it prevents tooth decay so they would not be trying to reduce the numbers in order to make the situation look better. Besides, these levels have been confirmed by other studies done in China, Turkey (7) and India.
Sodium Fluoride Content of Teas
Green 1.2-1.7 mg/L
Oolong 0.6-1.0 mg/L
Black 1.0-1.9 mg/L
Brick tea 2.2-7.3 mg/L
*Fluoride in 1% weight/volume tea prepared by continuous infusion from 5 to 360 minutes
It is interesting to note that the initial level of fluoride in green tea is higher that black tea so the concept that green is better than black does not hold water.
My next concern is the level of aluminium in tea that compounds the effects of sodium fluoride. Once you start to look into studies you realize that scientists are talking about aluminium and fluoride together in the same sentence. (3, 4) This has far reaching implications that go beyond the idea that a bit of fluoride helps tooth enamel.
It is also important to not overlook the effects of caffeine on the uptake of sodium fluoride. In their on-line drug reference manual 'Pharmacokinetics' section, the Medscape website states, "some studies suggested that oral bioavailability of fluoride may increase with concomitant administration of caffeine." (5) While it appears that caffeine can increase the absorption rate of sodium fluoride in the body, decaffeination does not solve this problem. One study showed how the process of decaffeination actually increased the level of sodium fluoride in the tea. (6)
A 2009 study conducted in Turkey showed that "herbal and fruit infusions were characterized by low values of ﬂuoride (0.02–0.04 mg/L) after 5 min of brewing and increasing brewing time to 10 min caused only slight increases in some infusions."(7) Tea grown in the same area had a very large amount of fluoride by comparison. It appears that the tea plant has the specific ability to absorb sodium fluoride and aluminium from the environment that other plants do not possess. It does not a matter what is put on the plant in the way of pesticides, herbicides or fertilizer, the plant collects these toxic minerals from the soil and water. In other words drinking organic tea may not be helpful in this case. It is also hard to know what constitutes 'organic' in places such as China, Turkey, Sri Lanka, India and Kenya. Though the tea plants may not be sprayed with pesticides, herbicides, etc. the soil and water the plants grow in is contaminated.
According to Dr. Michael P. Whyte, M.D. Professor of Medicine, Pediatrics & Genetics and Medical-Scientific Director, Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children, St. Louis, "The tea plant is known to accumulate fluoride from the soil and water," (8)
This is the doctor who conducted the study on Skeletal Fluorosis and green/black tea. (9)
"Says Dr. Whyte, "When fluoride gets into your bones, it stays there for years, and there is no established treatment for skeletal fluorosis. No one knows if you can fully recover from it." In other words, fluoride accumulates in your body." (8)
It is known that fluroride has an effect on thyroid function. After reviewing the evidence I would suggest that those with thyroid issues consider limiting their use of green tea and green tea products. For more information check out this particularly well written article "Green Tea, Fluoride & the Thyroid".
The author of this article sights "A major Canadian study published in 1995 reports average fluoride content in tea to be 4.57 mg/l in the 1980's." (10) I checked the Health Canada website which confirmed that they not only knew about the study, they funded it.
Considering the millions of tons of tea consumed worldwide every year, there is plenty of reason to keep the myth of tea's health benefits alive. No doubt there are some benefial compounds within the tea plant but at what cost to the body?
H. Wong Corresponding Author Contact Information, E-mail The Corresponding Author, K. F. Fung and H. P. Carr
Department of Biology, Institute for Natural Resources and Environmental Management, Hong Kong Baptist University, Kowloon Tong, Hong Kong
21 December 2002.
W. S. Shua, Z. Q. Zhanga, C. Y. Lana and M. H. WongCorresponding Author Contact Information,
a State Key Laboratory for Bio-control, School of Life Sciences, Zhongshan University, Guangzhou 510275, People’s Republic of China
b Institute for Natural Resources and Environmental Management, and Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, People’s Republic of China
19 June 2003.
J.T. Chana, S.H. Kohb
Vol. 30, No. 1, 1996
aDepartment of Basic Sciences and
bDepartment of General Dentistry, University of Texas Dental Branch, University of Texas Houston Health Science Center, Houston, Tex., USA
Caries Research (1996) 30:88-92 The average sodium fluoride concentration of infusions prepared from decaffeinated (green & black) tea were found to be 3.19 ppm and ranged from 1.01 to 5.20.
Ebru Emekli-Alturfana,*, Aysen Yarata, Serap Akyuzb
aDepartment of Biochemistry, Faculty of Dentistry, Marmara University, Nisantasi, 34365 Istanbul, Turkey
bDepartment of Pedodontics, Faculty of Dentistry, Marmara University, Nisantasi, 34365 Istanbul, Turkey
16 January 2009
Whyte MP, Totty WG, Lim VT, Whitford GM.
Division of Bone and Mineral Diseases, Washington University School of Medicine at Barnes-Jewish Hospital, St Louis, Missouri, USA.
Dabeka, R.W. (Health and Welfare Canada, Ottawa, ON, Canada.); McKenzie, A.D.
Journal of AOAC International (USA)
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