CALCIUM

Facts

• Calcium is the most abundant mineral in the body. It is also the fifth most common substance in the body after carbon, hydrogen, oxygen and nitrogen. Until about age 30, calcium re-absorption outweighs calcium loss, which results in increased bone density and growth. Following age 30, the body gradually loses calcium, resulting in gradual depletion of bone minerals.
• Heavy exercising hinders calcium's assimilation while moderate amounts of exercise improve its assimilation. Female athletes and menopausal women require increased amounts of calcium due to lower oestrogen levels.1 Oestrogen aids the skeletal system by promoting the deposition of calcium in the bone.
• Taking too much calcium can interfere with the absorption of zinc, magnesium and iron. Likewise high doses of magnesium, zinc and iron can interfere with the absorption of calcium.1
• Because calcium is slowly absorbed by the body, calcium supplements are more effective if they are taken in small doses throughout the day and at bedtime. Another reason to take calcium at bedtime: calcium is useful in promoting a sound, restful sleep.1

Functions

• Calcium is essential for the formation of strong bones and teeth and for the maintenance of healthy gums. It increases the rate of bone growth and prevents against bone loss associated with osteoporosis.1
• Calcium is important in the maintenance of a regular heartbeat and transmission of nerve impulses. Calcium helps lower cholesterol levels and helps prevent against cardiovascular disease and certain forms of cancer including colourectal cancer.2
• Calcium is important for normal blood clotting processes that aid in the early stages of wound healing. In addition, calcium also wards off the accumulation of an excess of acid or alkali in the blood.3
• It is involved in the activation of several enzymes including lipase, which breaks down fats for utilisation by the body. 1 In addition, calcium maintains proper cell membrane permeability, aids in neuromuscular activity and protects against pre-eclampsia in pregnancy, the number one cause of maternal death, according to Prescription for Nutritional Healing by James and Phyllis Balch.1

Requirements

The current Recommended Dietary Allowance (RDA) is 800mg.

Signs of Deficiency

A deficiency in calcium is associated with aching joints, eczema, brittle nails, elevated blood cholesterol, hypertension, heart palpitations, insomnia, muscle cramps, nervousness, rickets, tooth decay, rheumatoid arthritis, cognitive impairment, depression and, in severe cases convulsions and delusions.1,2

Safety

Individuals who suffer from recurrent kidney stones, have kidney disease, cancer, hyperparathyroidism or who take calcium channel blocking medication should consult a physician or health care professional before taking a calcium product. 2

Signs of Toxicity

Calcium intakes of several grams per day combined with vitamin D may result in calcium deposition in soft tissue. High doses of calcium can impair absorption of other minerals including iron, magnesium and zinc.

Current Research

Arthritis
According to the Nutrition Almanac, "arthritis, structural rigidity often caused by depletion of bone calcium, can be helped with regular supplements of calcium. Early consumption of calcium may help prevent arthritis. Rheumatism can also be helped with calcium therapy."3

Blood Pressure
Calcium supplementation can lower hypertension. Researchers at Cornell University Medical School studied 26 hypertensive adults and administered 2,000 mg of calcium. After six months, researchers found a "modest but consistent" drop in blood pressure from an average of 164/91 at the beginning of the study to 154/89 at the study's conclusion.4

Cancer
Researchers at Memorial Sloan-Kettering Cancer Center and Cornell University Medical College in New York found that when they gave 1,250 mg to individuals with a high family history of colon cancer, calcium reduced excessive cell duplication. Excessive cell duplication is often found in people that are susceptible to developing colon cancer. Before calcium supplementation, researchers found that cell proliferation was what they would expect in people prone to colon cancer. However, after two to three months on the calcium regimen, cell duplication, or proliferation, was lower, nearly comparable to that of people with a lower risk of colon cancer. The researchers theorised that calcium binds the bile and fatty acids, thereby reducing the irritation it can cause to the lining of the colon, which would decrease cell proliferation and, thus, colon cancer.4

Osteoporosis
Research shows that increasing calcium for children, adolescents, young adults, middle-aged women can increase bone density. However, according to Alexander Schauss, if one is desiring to develop or maintain bone mineral density, "an optimal intake of all nutrients essential to bone formation and homeostasis is required."5 In fact, two studies show that other micronutrients such as trace elements are needed for proper bone metabolism and re-absorption. In one study, a group of post-menopausal women were given a combined trace element and calcium supplement, a calcium supplement or placebo. In the group receiving the combined trace element and calcium supplement, bone density increased 1.48 %. In the group receiving only the calcium supplement, bone density decreased with an average of 1.25 %. For the placebo group, bone density decreased 3.53 %.6,7

In the second study, post-menopausal women on HRT were given a multi-vitamin, multi-mineral supplement containing 500 mg. of calcium, 600 mg. of magnesium, 2 mg. of copper and 10 mg. of manganese. Control subjects receiving the supplement experienced an increase in bone density from 0.303 g/cm2 to 0.337g/cm2.7,8

1 Balch, J.F. and P.A. Prescription for Nutritional Healing. Avery Publishing, 1997:pp23-24.

2 Barney, P. Doctor's Guide to Natural Medicine. Woodland Publishing, 1998.

3 Dunne, L.J. Nutrition Almanac, 3rd ed. McGraw-Hill Publishing Company, 1990: pp.66-68.

4 Prevention Magazine Staff. Complete Book of Vitamins and Minerals. Rodale Press, 1988: pp162-163;298-299.

5 Schauss, A. Minerals and human health: the rationale for optimal and balanced trace element levels. Life Sciences Press, 1995: pp.29-31.

6 Strause, L., Saltman, P., Smith, K.T., Bracker, M. and Andon, M.B. 1994, J. Nutr. v. 124, p. 1060.

7 Nielsen, F. The balderdash and realities of health and performance claims for supplements as exemplified by calcium, chromium and vanadium. Proceedings of North Dakota Academy of Science, 1999; v. 53.

8 Abraham, G.E., 1991 J. Nutr. Med. V. 2, p.165.

9 Matkovic V., Weaver C. Calcium. http://www.nutrition.org/nutinfo~calc.shtml.