I am 62 yr old woman who has medullary sponge kidney. visited er. found kidney stones on both sides. please advise on diet, supplements, & treatments.

Difficult: Your physician will advise you on specifics depending on what kind of stone has formed. It is near-certain that you'll be advised strongly to drink as much water as is feasible. Hopefully this will prevent you from having to limit the vitamin d that is benefiting your skeleton. This is a fairly common kidney problem; you didn't cause it and probably you can learn to manage it.

Many ways to prevent: Medullary sponge kidney is usually not serious but does increase risk of kidney stones. Fortunately supplements can dramatically reduce the incidence of kidney stones, esp. Magnesium and vitamins d, k2 and a (taken together). Drinking more water, avoiding fructose and excess salt helps too- see http://chriskresser.Com/how-to-prevent-kidney-stones-naturally for a good article on this.