The human body is able to absorb 500 to 600 milligrams of calcium at a time. The daily recommended dose for adults is at least 1,000 milligrams. As people age, they gradually lose bone mass, so daily calcium intake should increase to at least 1,200 milligrams.
Women over the age of 50 need more calcium than men in order to combat the onset of osteoporosis. The amount of calcium the body can absorb at a time stays about the same. Vitamin D is a necessary supplement to facilitate the absorption of calcium. Children up to three years old only need 700 milligrams or less of calcium per day.