What is Calcium?

Among minerals, calcium (CA) is the most abundantly present in humans, representing 52% of the body’s minerals content and amounting to 1.2% of the body weight.

In the elementary composition of the human body, calcium ranks fifth after oxygen, carbon, hydrogen and nitrogen, and it makes up 1.9% of the body by weight. Nearly all (99%) of total body calcium is located in the skeleton .The remaining 1% is equally distributed between the teeth and soft tissues, with only 0.1% in the extra cellular fluid (ECF)


Important for healthy bones and teeth; helps muscles relax and contract; important in nerve functioning, blood clotting, blood pressure regulation, immune system health.

  • Calcium Food Sources:
  • Milk and milk products; caned fish with bones (salmon, sardines); fortified tofu and fortified soy milk; greens (broccoli, mustard greens); legumes

  • Calcium Supplements:
  • When taken with a meal, the absorption is greatest when calcium is taken in doses of 500 mg or less.


Dietary calcium intake above or below the requirements can result in the irruption of several signs of deficiencies and excess.

  • Increased bone desorption.
  • reduce the rate of growth of the skeleton.
  • Rickets in children.
  • Calcium and Osteoporosiestimated at 3% per year in the first five years after menopause.
  • Loss in postmenopausal women.
  • Women with calcium intakes below 400 mg per day may benefit by increasing their dietary intakes or by taking supplements of calcium.

Calcium Toxicity:

  • High blood calcium may be asymptomatic or can cause constipation, nausea and vomiting, increased urination, thirst, muscle weakness, kidney failure, irritability, confusion, psychosis and coma.
  • Since the efficiency of absorption from large doses is poor, no adverse effects have been found with calcium supplements providing up to 2400mg/day.
  • However, in practice, an upper limit on calcium intake of 3 g is recommended by the FAO/WHO 2004.

Dietary Calcium Requirements:

  • The RDA for Indian adult male is based on replacing the losses of calcium in urine, stools, bile and sweat which is estimated to be 700 mg calcium per day.
  • The fractional absorption in adults is taken to be 20-30% in the presence of adequate vitamin D.