Caffeine, as anyone who must get to the bathroom the moment they walk in the door at work knows, is a diuretic. How much caffeine coffee has depends on the grind, the roast, the water temperature, and more. But just two average cups may increase the risk of kidney stones if you have had them before.
Caffeine seems to pull calcium from the bones in some people, like phosphorus (read: soda!) does. And most kidney stones are made up of calcium and oxalate. A new study shows that people who have had stones have more urinary calcium after coffee, and the same amount of oxalate.
So a word to those who have had the incredibly painful experience of kidney stones: decaf. Really good organic decaf .
What else can you do? Limit animal protein to 8 ounces or less, and salt to 3 grams or less each day, and all foods high in oxalate: nuts (walnuts, peanuts, almonds, hazelnuts, etc.), spinach, okra, beets, rhubarb, strawberries, cranberries, soy, wheat bran, brown rice. And drink: 3 liters of water daily.