Does drinking too much tea cause kidney stones?

Question

A quick Google search provides several pages that suggest drinking tea can lead to kidney stones.

For example:

Avoid drinking too much tea or coffee.

-Victorian Government's Better Health site

The consensus theory seems to be that oxalate and other minerals in tea form salts crystals in the urinary system (stones).

However, the Mayo Clinic reports:

Drinking a cup of black tea or green tea each day could reduce the risk of kidney stones. One study in women found those that drank the most black tea had a slightly lower risk of kidney stones. The study was not rigorous and only involved women, so it doesn't provide strong evidence that drinking tea is helpful for all kidney stones. If you enjoy drinking tea, there may be a chance that continuing to drink tea can help reduce your risk of kidney stones. However, tea contains high oxalate levels. So if your urine has a high oxalate level, your doctor may advise against drinking tea.

Source.

Does drinking too much tea cause kidney stones?

Answer 1

Referring to MIC, "limited research suggests that tea consumption may be associated with fewer cavities and a slightly lower risk of kidney stones, but more research is needed to confirm these findings."

Two large prospective studies found that the risk of developing symptomatic kidney stones decreased by 8% in women and 14% in men for each 8-ounce (235 mL) mug of tea consumed daily. A study in rats concluded that the antioxidants in green tea may be involved in inhibiting calcium oxalate precipitation and thus kidney stone formation. The implications of these findings for individuals with a previous history of calcium oxalate stone formation are unclear. High fluid intake, including tea intake, is generally considered the most effective and economical means of preventing kidney stones. However, tea consumption has been found to increase urinary oxalate levels in healthy individuals, and some experts continue to advise people with a history of calcium oxalate stones to limit tea consumption.

The claim of connection between oxalate (a chemical known to cause calcium stones) and iced tea to cause kidney stones is debunked by Dr. Mike Nguyen here and Taylor Kubota here.