I dont have a comment about teas, however I do have a comment about carbonated drinks, with sugar or without....
Years ago I would get up & start drinking Dr Peppers indiscriminately thru the day ( about 8 12oz cans a day Id say) and I was having a problem with my intestines and bloating & EXTREME pain.... I couldnt figure out what it was & the docs I went to told me it was just IBS and to live with it.....

Well, one day there werent any DrPeppers in the coke machine at work so for one day I didnt get my sodas because I didnt like any of the others & would rather do without.

I noticed that day by lunchtime that my guts werent killing me and my pants werent tight from swollen intestines and trapped gas that day. On a normal day my early morning jean size would be 1-2 sizes smaller than my afternoon/evening size jean size because of the swelling.

The only thing different in my life at that point is that I wasnt drinking soda. I thought about it & wondered if it could have been that. I made a note to analyse the situation the next time I drank sodas & I would test myself a few days here & there to see what happens when I did & didnt drink sodas.

There was NO DOUBT..... when I drank carbonated beverages of ANY TYPE my intestines swell and swell and swell and I become extremely miserable and in ALOT of pain.

Today its a rare day that I drink a carbonated drink though I do have one every so often.

My brother in law was taken to the doctor with alot of symptoms of feeling really really weak that had been building up & the end result after many many tests was that his PH was abnormal because he drank "too many" carbonated beverages.

I just wanted to share these stories with you, not to scare you, but to make you aware of what consuming ALOT of carbonated drinks can do to you.