Person at risk of calcium deficiency

Elderlies who tend to have a lower production of digestive acids
Woman with repeated pregnancy and lengthy breast-feeding
Pregnant adolescents have high calcium needs
Breast-feeding women: they need an extra 550 mg of calcium daily (a nursing woman can lose up to 300 mg of calcium daily in breast milk)
People who drink soda pop. These drinks have added phosphoric acid (phosphate) which imbalance the ratio phosphorus/calcium.