Blue Gypsie wrote:Jeff,
I noticed on your website (in the Real Superfoods article) that you do not consume green tea. Can you elaborate on this more? In Dr. McDougall's October 2004 newsletter he says that tea is beneficial. What about decaffinated tea (green or black)?
Your comments and thoughts would be appreciated?
Thanks,
Blue Gypsie
As always, everything has to be put into perspective.
My main point of the article is that without the basis of a healthy diet and lifestyle, none of those super foods will do you any good, and if you have an unhealthy diet, these super foods are not going to save the day.
I would also not consider tea a "food" as a food is something that must be able to sustain life. As tea has no calories and virtually no minerals or vitamins, it can not sustain life in and of itself and is not a food and so does not belong on any list of foods (good or bad).
While tea is often touted for its potential health benefits, and I have no concern if someone wanted to include it occasionally as part of their healthy diet, there are also a few potential health concerns.
Like seaweed, tea is a bioaccumulater and can accumulate large levels of certain chemicals. a few of these can be a health concern. Tea is natural bioaccumulator of aluminum with aluminum concentrations of up to 30,000 ppm aluminum by dry weight. Aluminum is a known neurotoxic element and is found in varying quantities in tea. Studies have found concentrations of aluminum in infusions of green and black teas that range from 14 to 27 micrograms per liter (μg/L) to 431 to 2239 μg/L which vary due to soil conditions and water quality. Aluminum can accumulate in the body and cause osteomalacia and neurodegenerative disorders, especially in individuals with renal failure. Currently, it is not clear how much of the aluminum in tea is bioavailable, and there is no evidence of any aluminum toxicity associated with drinking tea. However, I think knowing about this is important especially since aluminum is now a suspect in Alzheimers.
Tea also contains fluoride and again, can absorb the amount of flouride at a greater rate than many others plants. The actual amount depends on the picking method and the fluoride content of the soil in which it is grown. Very high fluoride intake (over 2 mg per day for children, 4 mg adults) increases the risk of osteofluorosis and fractures. There is some evidence relating the over-intake of teas to fluorosis in humans.
Tea may inhibit iron bioavailability from the diet which may be important for individuals who suffer from iron-deficiency anemia.
Tea contains caffeine and again, while there is little evidence of harm, in certain individuals excess caffeine can cause tachycardia, palpitations, insomnia, restlessness, nervousness, tremors, headache, abdominal pain, nausea, vomiting, diarrhea, irritability, tremor, heartburn, dizziness, ringing in the ears and diuresis in certain people.
Tea contains oxalate, of which the over consumption of can cause kidney stones, as well as binding with free calcium in the body. Oxalates may also bind to other minerals as well.
Although rare, some people develop adverse allergic reactions to tea.
Pregnant women may want to avoid drinking tea during the early part of a a pregnancy because excess intake has been linked to neural tube birth defects because tea can interfere with the absorption of folic acid.
Also, while the data is limited, drinking beverages at very high temperature (as in hot tea) may increase the risk of esophageal cancer.
In Health
Jeff Novick,
by Blue Gypsie » Mon Mar 10, 2008 8:03 am 
