About UNHCR. The Office of the United Nations High Commissioner for Refugees was established on December 14, 1950 by the United Nations General Assembly. The agency is mandated to lead and co-ordinate international action to protect refugees and resolve refugee problems worldwide.
1 If you tend to form calcium oxalate stones, your doctor may recommend restricting foods rich in oxalates. 2  These include rhubarb, beets, okra, spinach, Swiss chard, sweet potatoes, nuts, tea, chocolate and soy products.
Kidney Stones. Spinach contains a naturally occurring substance called oxalate. In rare cases, eating extreme amounts of oxalate-rich foods like spinach, nuts, pepper and rhubarb can lead to a condition called hyperoxaluria, in which oxalate crystals combine with calcium in the kidney and form kidney stones.