Hypothyroidism occurs when thyroid hormones are suppressed. There may be other health problems associated with goitrogenic effects before full-blown thyroid dysfunction. Iodine is one of the most important minerals needed by the body. The following research reveals that green and black tea, etc., can hinder thyroid function, etc
“A significant decrease in serum T3 and T4 and increase in TSH levels has been reported along with decreased TPO and deiodinase activity in response to dietary green tea extract in rats...A recent study conducted to see the effect of catechins, the flavonoids in green tea on thyroid physiology in rat model concluded decreased activity of thyroid peroxide and 5’-deiodinaseI enzymes. Decreased levels of serum T3 and T4 along with significant elevation of TSH was noted…”
(J Clin Diagn Res. 2016 Jan)
“…these results suggest that catechin present in green tea extract might behave as antithyroid agent…”
(Chandra AK, De N. "Goitrogenic/antithyroidal potential of green tea extract in relation to catechin in rats." Food and chemical Toxicology. 2010;48:2304–11)
“Green tea is a worldwide used beverage rich in fluoride and caffeine…Schmidt et al., (2005) studies showed that excessive consumption of green tea caused some hazards like liver cells acute cytotoxicity. Thyroid is an endocrine gland that shares in the control of body metabolism by secreting the thyroid hormones, triiodothyronine (T3) and thyroxine (T4). These hormones also control the growth and function of many other body systems (Zhao et al., 1998). Some studies found that green tea extract induced an enlargement in the thyroid of normal rats (Sakamoto et al., 2001; Satoh et al., 2002)…In addition to the enlargement of thyroid gland, Chandra, De, and Choudhury (2011) declared that green tea extract decreased the serum level of both T3 and T4…green tea is a major source of fluoride intake…overuse of caffeine is addictive and has other hazards as thyroid carcinogenesis (Peterson et al., 2005; Sinija & Mishra, 2008)… in this present study, the effects of high doses of green tea, fluoride and caffeine on the thyroid gland weight and hormones was evaluated to confirm if green tea had an effect on thyroid gland and if so, it was due to its content of fluoride and caffeine or not…Our study showed a significant decrease in serum levels of both T4 and T3 in the GT treated group in comparison to the control one…Our results showed a significant decrease in serum levels of both T4 and T3 in the FL treated group in comparison to the control one…Our results cleared that there was a significant decrease in serum level of T3 without a significant change in serum T4 in Caf treated group in comparison to that of the control group… On the other hand, E Spindel et al., (1980) found a significant decrease in both serum T4 and T3 following caffeine administration… Son et al., (2003) found thyroid changes with high doses of caffeine in rats with iodine deficiency. From all the previously discussed results of our study, it is clear that green tea decreased thyroid hormones…Also, high doses of fluoride decreased thyroid hormones… Moreover, high doses of caffeine decreased T3 without significant changes in T4…”
(Abulfadle K. A., et al, Effect of Excessive Green Tea versus Fluoride and Caffeine on Body Weight and Serum Thyroid Hormones in Male Mice)
“…Fluoride in tea is much higher than the Maximum Contaminant Level (MCL) set for fluoride in drinking water…Tea leaves accumulate more fluoride (from pollution of soil and air) than any other edible plant…Fluoride content in tea has risen dramatically over the last 20 years, as has tea consumption… A website by a pro-fluoridation infant medical group lists a cup of black tea to contain 7.8 mgs of fluoride…which is roughly the same amount as if one were to drink 7.8 litres of water in an area fluoridated at 1ppm. It is well known that fluoride in tea gets absorbed by the body similarly as the fluoride in drinking water… Some British and African studies from the 1990's showed a daily fluoride intake of between 5.8 mgs and 9 mgs a day from tea alone… one needs to realize that the level of fluoride at 1 part-per-million (ppm) = 1 mg/l was set in the 40's when TOTAL intake was considered to be only about 1 mg/day in areas with fluoridated water. It was thought that the fluoridation of water supplies at 1 ppm (1 mg/l) would duplicate this intake, assuming that people would drink 4 glasses of water a day. However, average current total intake of fluorides is approaching the 8mg/day range, according to the last official data available from the US PHS (1991) and other publications…Drinking a cup of tea with fluoride content as mentioned above (7.8mg) would mean a fluoride intake much higher(!) than amounts which were actually given as medication to treat hyperthyroidism (-> over-functioning thyroid) for numerous decades - in several countries - specifically to reduce thyroid activity!... Existing studies tend to concentrate on active ingredients of green tea, such as epigallocatechin gallate (EGCG), a compound that belongs to a family of antioxidants known as polyphenols. EGCG and other polyphenols are constituents of tea - especially of green tea…However, no studies exist investigating the effects of fluorides on these anti-oxidants. Existing studies involving other antioxidants and fluoride compounds give evidence that fluorides can adversely affect the action of antioxidants… While lung cancer studies have shown an inverse effect with Okinawan tea, a tentatively increased risk was shown in another study, clearly indicating that more research into this matter is needed. In a recent study on Finnish men, published in 1998 by Terryl Hartman and others, again a positive correlation between colon cancer and tea intake was found. Colon cancer occurrence increased with higher intake… Many available green tea/cancer studies last only a few months, and do not take into account the cumulative effects of fluoride, which is a known cancer promoter, and has the ability to transform healthy cells into cancerous ones… Dean Burk, for many decades Chief Chemist at the National Cancer Institute, testified at congressional hearings in 1981 stating that over 40,000 cancer deaths in that year were attributable to fluoridation…He has said that no chemical causes as much cancer, and faster, than fluorides… Dental fluorosis (mottled teeth) is the first visible sign of fluoride poisoning… The first study to investigate fluoride content in decaffeinated teas found an even higher fluoride content in those teas as compared to their caffeinated counterparts… It is thought that this is due to the high fluoride content in the water involved in the de-caffeination process, which then would also make coffee similarly decaffeinated high in fluoride content… In addition, the caffeine in tea has a great augmentative effect on the bio-availability of fluoride. In 1990 researchers at the University of Texas even theorized that ‘the rise in incidence of dental fluorosis in North America is mainly due to the replacement of water intake by caffeine-containing beverages among the young population’… To make matters much worse for human health, fluorides in teas are found together with aluminum. The combination of aluminum and fluorides in tea is of urgent concern, due to the increased damage done by fluorides when in the presence of aluminum, especially neurological and renal damage)… In a study by Dr. Robert Isaacson at the State University of New York, aluminum fluoride was added to the rat’s diet. This, contrary to normal expectations, passed through the brain barrier and gave the rats short term memory, smell sensory loss, unsteady gait, and loss of structures of the neo-cortex and hippocampus, all symptoms of Alzheimer's… Thyroid hormones are extremely important in the regulation of metabolic processes and brain development. Every cell in the body depends upon thyroid hormones for regulation of their metabolism… It is only in the last two decades during which endocrinology has progressed so rapidly, that now over 150 symptoms and associations can be identified in hypothyroidism. Almost all correlate with known symptoms of fluoride poisoning… We have posted over 100 studies documenting the adverse effects of fluoride on the thyroid gland from the last 70 years or so in the Virtual Library on Fluoride Research (78)at: http://www.bruha.com/fluoride/html/thyroid_studies.htm... Many studies on thyroid hormones have shown that attention deficit and/or hyperactivity disorders in children are linked to changes in the levels of thyroid hormone in the blood, and that irritability and aggressive behaviour are linked to thyroid hormone levels and hypothyroidism… Visual and auditory hallucinations may result from altered perception and have been misdiagnosed as schizophrenia or psychosis. Other behavioral symptoms have included fear - ranging from mild anxiety to frank paranoia, mood swings and aggression… Many psychoactive drugs including Prozac, Paxil and Luvox (Littleton) are fluorinated medications. Rohypnol, the infamous date-rape drug, is fluorinated Valium, which is about 20-30 times more potent than Valium alone… Thyroid hormone disorders may induce almost any psychiatric symptom or syndrome, including rage… Could it be that the world-wide 'iodine deficiency' is actually fluoride excess?..."
"Sodium Flouride in Black & Green Tea...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'...According to the calculations made by the Oregon State University's Linus Pauling Institute Micronutrient Research Centre, all tea has a higher level of sodium fluoride than the City of Ottawa's fluoridated drinking water...These calculations were made from tea that was brewed using water that wsa not fluoridated, so the flouride levels when using flouridated water would be compounded. It's important to note that the Linus Pauling Institute (LPI) website doesn't state any problem with fluoridation – it's felt that flouride prevents tooth decay, so LPI 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 and India...It's interesting to note that the initial level of fluoride in green tea is higher that black tea, so the concept that green is universally better than black does not hold water. My next concern is the level of aluminium in tea which compounds the effects of sodium fluoride...It is also important to not overlook the effects of caffeine on the uptake of sodium fluoride. In their online drug reference manual, Pharmacokinetics, the Medscape website states, 'some studies suggested that oral bioavailability of fluoride may increase with concomitant administration of caffeine'...While it appears that caffeine can increase the absorption rate of sodium fluoride in your 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...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 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...Considering the millions of tonnes of tea consumed worldwide every year, there is plenty of reason to keep the myth of tea's health benefits alive. There's also no doubt that there are some beneficial compounds within the tea plant...though at what cost to your body?"