I drink a fairly high amount of black tea (about 1.5L/day) and I had read about this before a bit, but couldn't find any clear answers - what's the risk of developing kidney stones and will I have fair warning signs before permanent damage?
Contents of Oxalate:
black tea 15 grams for 1 liter equals 15 * 5.11 = 76.65 milligrams of soluble oxalates
Spinach has 645 milligrams of soluble oxalates per serving size!
Cola sodas has 0 as in ZERO soluble oxalates per serving size.
My doctor told me that was all new to him. I stopped going to him as a doctor. I ate spinach everyday. I stopped eat spinach I stopped having kidney stones.
http://apjcn.nhri.org.tw/server/apjcn/11/4/298.pdf
"The results from this experiment show that while a regulartea drinker would be consuming oxalate every day, the levelsare modest when compared to the amounts of oxalate thatcan be found in other common foods. It would be verydifficult to consume an excessive amount of soluble oxalatefrom the regular consumption of black tea without milk. Theconsumption of black tea with milk would mean that smallamounts of oxalate would be absorbed on a daily basis andwould place black tea in the low risk group of foods, asdefined by Noonan and Savage".
Seems like damage is minimal and only some people will form calcium stones to begin with. For me this means I'm not going to make any concern out of it unless I hit an issue.
I did find one oft-repeated anecdotal case of a guy who consumed ~4L+ of iced tea per day and had more major issues, but I didn't see any other examples of this.