i know with me the kidneys are my weak link due to mercury damage.
do you get excess bubbles that linger in the bowl when you pee? thats proteinuria(sp?). the semi-permeable membrane is damaged and allowing larger particles through than it should. the bubbles are protein from the blood, like egg whites form bubbles. it can also be a sign of heading for renal failure.
i use peach leaves for a kidney tonic. barefoots kidney cleanse did me a world of good, too.