Foods with the most calcium include baking powder, unsweetened rennin tablets, table salt, bottled Perrier water and canned butterbur. Rennin, also called chymosin, is an enzyme that is formed in the stomachs of calves and other baby ruminants that allows them to digest milk.
Perrier water is a sparkling spring water that was first bottled in 1863 in a town in the south of France. According to Fine Waters, Perrier contains 147.3 milligrams of calcium per liter. Other minerals, such as magnesium and potassium, make Perrier a very hard mineral water. Most bottled waters are good sources of calcium.
Butterbur is an herb used to treat stomach problems, coughing, pain, hay fever and insomnia. Scientists believe butterbur has chemicals that reduce the inflammation that leads to these conditions.
Other foods high in calcium are apple-cider-flavored drinks fortified with vitamin C, nopales, raw watercress, tofu and ready-to-eat cereals. Nopales are prickly pear cactus pads. They are used medicinally, but also as food in salads, soups and other preparations. Raw epazote is also high in calcium, as are amaranth leaves, mustard spinach, turnip leaves, lemonade with aspartame, and frozen, uncooked rhubarb. Other calcium-rich foods are dried basil, raw Chinese cabbage and lamb quarters.