An average diet contains 1,200 mg of calcium, one-third of which is absorbed.
In normal adult humans, new bone formation takes up about 400 mg of calcium per day, an amount approximately equal to that in the circulating blood.
From the fourth decade on, resorption exceeds formation, resulting in an approximate 10 percent loss in bone mass per decade, equivalent to a daily loss of 15 to 30 mg of calcium.
The Food and Nutrition Board of the U.S. National Academy of Sciences has recommended 1,000 to 2,000 mg of calcium daily for adults and 800 to 1,300 mg for children.
The percentage of children and adolescents who consumed more than 1,000 mg of calcium per day were 54.8% and 48.7%, respectively.
Findings from both studies suggest female athletes and military recruits who consumed greater than 1500 mg of calcium daily exhibited the largest reduction in stress fracture injuries.
Participants were accustomed to dietary calcium intake of ∼ 830 mg/dayearsearsupplementedted individuals received additional ∼ 670 mg of calcium per day/7 years.
Study Design: Sixty postmenopausal women, aged 45 to 56 years, were randomized in an open-label, 2-year trial that compared treatment with low-dose continuous combined hormone replacement therapy that contained 0.3 mg of conjugated equine estrogens and 2.5 mg of medroxyprogesterone acetate plus 1000 mg of calcium per day or treatment with 1000 mg of calcium per day alone.
The present study was designed to measure the effects, on parathyroid function and bone metabolism, of ingestion of high-calcium mineral water and of a calcium salt bringing the same dose (600 mg) of calcium as a reference.
Fifteen healthy young men (mean ± SD age : 23.3 ± 1.2) ingested, during 3 different experimental periods chosen at random, a) high-calcium mineral water (596 mg/L), b) low-calcium mineral water as a control assay, c) one bag of tricalcium phosphate powder containing 600 mg of calcium.
Treatments consisted of a control diet that contained no B-vitamins, a biotin diet that contained 0.87 mg of biotin per kilogram of dry matter (DM), a pantothenic acid diet that contained 21 mg of pantothenic acid per kilogram of DM, and a biotin plus pantothenic acid diet that contained 0.87 mg of biotin and 21 mg of calcium pantothenic acid per kilogram of DM.
