The National Academy of Sciences has established guidelines for calcium that are 25–50% higher than previous recommendations. For ages 19 to 50, calcium intake is recommended to be 1,000 mg daily; for adults over age 51, the recommendation is 1,200 mg daily. The most common supplemental amount for adults is 800–1,000 mg per day. General recommendations for higher daily intakes (1,200–1,500 mg) usually include the calcium most people consume from their diets. Studies indicate the average daily amount of calcium consumed by Americans is about 500–1,000 mg.