Coral calcium is a salt of calcium derived from fossilized coral reefs. Coral calcium is composed of calcium carbonate and trace minerals. Claims for health benefits unique to coral calcium have been discredited. Coral calcium, marketed as a cure for various diseases and linked to Okinawan longevity, is merely calcium carbonate and can be considered a calcium supplement, and it supposed superiority to regular calcium carbonate has not been proven. The Okinawa Centenarian Study (OCS) in 2003 clarified that Okinawan longevity is due to a healthy lifestyle, not coral calcium. The OCS did not endorse coral calcium due to its cost, lack of scientific evidence supporting health claims, and environmental concerns about coral reefs. In 2004, the US Federal Trade Commission prohibited the marketers from making unsupported health claims about coral calcium.