[Soliloquy]

this site http://www.kombuchaessence.com/why_kombucha.html has a brief overview of some of the nutrients in kombucha.

Here's more

Glucuronic acid
The body's most important detoxifier. When toxins enter the liver this acid binds them to it and flushes them out through the kidneys. Once bound by glucuronic acid toxins cannot escape. A product of the oxidation process of glucose, glucuronic acid is one of the more significant constituents of Kombucha. As a detoxifying agent it's one of the few agents that can cope with pollution from the products of the petroleum industry, including all the plastics, herbicides, pesticides and resins. It kidnaps the phenols in the liver, which are then eliminated easily by the kidneys. Kombucha can be very helpful for allergy sufferers. Another by-product of glucuronic acid are the glucosamines, the structures associated with cartilage, collagen and the fluids which lubricate the joints. It is this function that makes Kombucha so effective against arthritis.

http://www.seedsofhealth.co.uk/ferme...kombucha.shtml
I don't consider myself an expert but, from the reading I've done, you do need to use real tea (not herbal "tea" that's made from plants other than the tea plant) to get all of the benefits. I've read that black tea & white sugar produce the most glucoronic acid--but you can use green or white.

Types of Tea for Kombucha
Kombucha requires tea for its fermentation (Camellia Sinensis). That's real tea not herbal tea. It can be also be sensitive to strong aromatic oils. A tea like Earl Grey that contains Bergamot oil, can sometimes kill or badly affect the culture. There are several different kinds of tea that give different results from lighter tastes to stronger more cider like tastes.

Black Tea
Black tea is made from leaves that have been fully fermented. The leaf is spread out and left to wilt naturally, before being fired, producing a deep, rich flavour and an amber brew.

Oolong Tea
Oolong tea is half way between green tea and black tea. It's gently rolled after picking and allowed to partially ferment until the edges of the leaves start to turn brown. Oolong combines the taste and colour of black and green tea.

Green Tea
Green tea is withered then steamed or heated to prevent oxidation and then rolled and dried. It is characterized by a delicate taste, light green colour. The Japanese tea Sencha makes an especially fine kombucha.

White Tea
White Tea is the rarest and most delicate of tea. Plucked forty-eight hours or less between the time the first buds become fully mature and the time they open. Unlike black and green teas, white tea isn't rolled or steamed, but simply aired dried in the sun, this preserves more of its antioxidant properties. White tea has about three times as many antioxidant polyphenols as green. White tea represents the least processed form of tea.

http://www.seedsofhealth.co.uk/ferme...kombucha.shtml