MINERALS: Calcium

Functions of calcium
Deficiency of calcium
Recommended dietary allowance for calcium
Food sources of calcium
Toxicity of calcium
References

Calcium

The average Western diet contains slightly less than the recommended daily allowance of Calcium, so some deficiency is quite common, especially among post-menopausal women. Calcium is the major constituent of bone and tooth material, so we need more of it than any other mineral. The average human body contains more than 1 kilo of calcium and about 1g a day is required to maintain that level. Dairy products like milk and hard cheese - especially the lower-fat varieties - are good sources of calcium. Tinned sardines are also good.

Functions of calcium

Builds and maintains bones and teeth.
Regulates heart rhythm.
Helps regulate the passage of nutrients in & out of the cell walls.
Assists in normal blood clotting.
Helps maintain proper nerve and muscle function.
Lowers blood pressure.
Is important to normal kidney function.
Reduces the incidence of colon cancer (under research)
Reduces blood cholesterol levels.

Deficiency of calcium

Arm and leg muscles spasms, softening of bones, back and leg cramps, brittle bones, rickets, poor growth, osteoporosis ( a deterioration of the bones), tooth decay, depression.

Recommended dietary allowance for calcium

The recommended upper level of calcium is 2.5 g/day.

Food sources of calcium

Milk, cheddar cheese, sardines, free range eggs, leafy green vegetables. A glass of low fat milk, a low fat yogurt and 2oz of lower fat cheese provides the average person with the Calcium they need.

Toxicity of calcium

Symptoms of calcium toxicity are rare. Excess calcium supplementation has been associated with some mineral imbalances such as zinc.

References

Jackman, L. A., Millane, S.S., Martin, B. R., Wood, O. B., McCabe, G. P., Peacock, M. & Weaver, C. M. (1997) Calcium retention in relation to calcium intake in postmenarcheal age in adolescent females. Am. J. Clin. Nutr. 66: 327-333.
Martin, A. D., Bailey, D. A., McKay, H. A. & Whiting, S. (1997) Bone mineral and calcium accretion during puberty. Am. J. Clin. Nutr. 66: 611-615.
Dawson-Hughes, B., Harris, S.S., Krall, E. A. & Dallal, G. E. (1997) Effect of calcium and vitamin D supplementation on bone density in men and women age 65 and older. New Engl. J. Med. 337: 670-676.