What is Oxalic Acid and how much is in a cup of tea?
Oxalic acid is a naturally occurring component of tea,
chocolate, beer, soybeans, wheat germ, some fruits and vegetables,
and is especially high in spinach and other dark leaf greens.
Oxalic acid is usually excreted in urine as a harmless by-product
of digestion and assimilation, however it can also combine with
minerals, and particularly with calcium, to form oxalates.
These oxalates are salt crystals that can be irritating to human
tissue and can contribute to the formation of kidney and bladder
stones. This is especially a concern for those who have kidney or
bladder problems or those with an inability to properly absorb
Of all the tea types, black and black decaffeinated teas contain
the most oxalic acid, typically ranging from 12 to 30 mg per cup.
Green, green decaffeinated and white teas typically contain 6 to 18
mg oxalic acid per cup. However test results tend to vary
cup-to-cup and some of our independent laboratory testing of oxalic
acid content has resulted in quantities too small to be measured or
to contain none at all.
Herbal teas typically contain only 0 to 2 mg oxalic acid per
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