Calcium and Phosphorus Requirements

BY ROBERT A. STEVENSON, D. D. S., R. Ph. Dental Therapy Editor

                In presenting this short article on the very complicated and far from thoroughly understood subject of calcium metabolism, no endeavor will be made to cover the subject completely as this would be impossible in the space allotted to us, but we merely hope to touch a few of the better known conditions in an effort to create a greater interest in what is becoming a subject of increasing importance to us.

At the present time it would appear that if we are to solve the problem of caries of the teeth we must reach out beyond the local condition. Is it not logical to presume that metabolic conditions that affect the rest of the skeletal structure can also affect the teeth?

Metabolism—The object of digestion is to render the food capable of absorption into the circulatory fluids—the blood and lymph.

The absorbed food products are then transported to the various organs and tissues of the body, where they are either used at once or stored away for future requirements.

Calcium is of first importance with regard to the minerals.

The large amount of calcium and the associated phosphate and carbonate in the skeleton (including the teeth) makes this organ the chief site, quantitatively, of the mineral stores.

The factors in normal calcification involve at least the following:

1—Intake of calcium and phosphorus.
2—Ratio of Ca/P.
3—Effect of heavy metals.
4—Acid base.
6—Vitamin C.
7—Vitamin D.
10—Other glands.

It has been demonstrated that either low calcium or low phosphorus can be a limiting factor in body growth.

The calcified tissues of the animal body become abnormal through pathogenic conditions, unsuitable diet, or activity or inactivity of the endocrine organs. Included are, such diseases as rickets, osteomalacia, osteoporosis, etc., of bone and caries of the teeth.

The abnormal conditions mentioned above are those connected with general disturbance of nutrition. Rickets occurs in children and young animals and is characterized by (a) enlargements at the epiphyseal junctions; (b) softening and bending of the bones and their stunted growth; (c) abnormal proliferation of the epiphyseal cartilage; (d) formation of bonelike tissue deficient in calcium salts.

It has been found that this disease may be produced in a young growing animal by a deficiency of calcium, phosphate, or vitamins C and D in the diet. Provided that the intake of calcium and phosphate is normal, rickets may be cured by the addition of vitamin D to the diet or by the ultraviolet light treatment.

From the present knowledge of the relationship between vitamin D and the parathyroid and their effect on bone structure, it is considered that vitamin D controls the absorption and excretion of calcium through the intestinal wall. The parathyroid regulates the blood calcium and probably stimulates the formation of osteoblasts and osteoclasts.

McCollum and associates produce, with low calcium diets, not only rickets but lessened growth.

With large calcium intakes, large calcium retentions occurred. The calcium requirement is intimately connected with the phosphorus intake.

McCollum and associates demonstrated that, with vitamin restriction, rickets and diminution in growth could be produced with high calcium—low phosphorus diets. Ca/P 4 when the latter investigator added phosphorus to change the Ca/P ratio to 2, rickets was prevented.

The method of absorption and mode of action of irradiated ergosterol remains undetermined.

Harris points out that the parathyroid is independent at vitamin D, the former raises the blood calcium by drawing it from the body.

Hypoplasia of the Teeth—This is seen animals particularly horses. When the diet contains the anticalcifying factors present in cereals with little vitamin D. This causes interglobular spaces in the dentine and poorly developed enamel.

Teeth that are hypoplastic are prone to dental caries. In caries well calcified, secondary dentine is developed when there is plenty of vitamin D the diet. Vitamin D controls the calcification of alveolar bone and other calcified tissue.

Recently there has been isolated a phosphatase. (an enzyme present in the osteoblasts) from teeth similar to that found in bones.

That a deficiency of vitamin D in the diet is conducive to caries is not generally accepted. Sampson and Sprawson support this theory, but Fish is opposed to it.

Faulty calcification of teeth, and especially the cause and prevention of dental caries, has been the subject of many recent investigations, various causes being given such as vitamin D, vitamin A, vitamin C, Ca/P, heredity, candy, soft foods, general health, general diet, and may other causes. Where there are so many explanations, it is obvious that the problem is still unsolved.

A Textbook of Biochemistry, Edited by Benjamin Harrow and Carl P. Sherwin. Published by W.B. Saunders Company 1935.