The New York Times is reporting that kids are now getting kidney stones.:

A Rise in Kidney Stones Is Seen in U.S. Children
To the great surprise of parents, kidney stones, once considered a disorder of middle age, are now showing up in children as young as 5 or 6....
http://www.nytimes.com/2008/10/28/health/28kidn.html?_r=1&8dpc&oref=slogin


Here is what Chris Masterjohn wrote about kidney stones in his Vitamin K2 article:
The kidneys likewise accumulate large amounts of vitamin K2 and secrete vitamin K-dependent proteins that inhibit the formation of calcium salts. Patients with kidney stones secrete this protein in its inactive form, which is between four and twenty times less effective than its active form at inhibiting the growth of calcium oxalate crystals, suggesting that vitamin K2 deficiency is a major cause of kidney stones.

According to the NYT, doctors are recommending a low-salt diet. How about cheese and butter from pastured animals?