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)

Functions

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.

Deficiency:

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.