Vitamin D Benefits

Cod liver oil has been used in the treatment of rickets for more than 100 years but it was not till 1918. Sir Edward Mellanby made things clear by his studies that rickets is the nutritional disease responding to a fat soluble vitamin in cod liver oil. This vitamin D was finally prepared in a pure form in 1931.

image by carlafida

Vitamin D otherwise described as calciferol. It is further divided in to two compounds i.e. cholecalciferol (D3) and another one is ergocalciferol (D2). Both are essential to prevent rickets (anti –rachitic).

These are all sterols chemically related to cholesterol and to the hormones of the adrenal cortex and sex glands. Certain sterols on exposure to ultraviolet irradiation undergo a small structural change which makes them antirachitic.

Among all sterols only two activated sterols are of importance in nutrition and therapeutics.  These were first described as vitamin D2 and D3 and are still known by these labels. The material originally described as vitamin D1 was subsequently shown to be an impure mixture of sterols.

Vitamin D2 differs chemically in having a double bond and a methyl group in the side chain. It is manufactured by the action of ultra violet light on ergo sterol, a sterol found in fungi and yeast. Although used in therapeutics, it occurs very rarely in nature.

Vitamin D3 is the natural form of vitamin D. It is produced by the ultraviolet irradiation of 7-dehydrocholeserol, a sterol widely distributed in animal fats, such as the oily secretions of mammalian skin and the oil of the preen glands of birds.  Activation of 7-dehydrocholesterol takes place when the surface of the body is exposed to sunlight.  In man the vitamin so formed enters the body directly by way of the skin. In other mammals and birds the entry is by ingestion through the gut, as a result of licking the fur or preening the feathers.

image by hansika345

The liver oil of fish is very rich in vitamin D3, probably from ingestion of microscopic plankton that lives near the surface of the sea and are hence exposed to the sun rays. Ingested vitamin D requires the presence of bile and probably fatty acids for its absorption in the gut.  It is stored in the fatty tissues of the body. One clearly defined action of vitamin D in the body is that it promotes the absorption of calcium from the gut, thus ensuring a sufficient supply of calcium in the extra cellular fluids bathing the growing points of the bones. Here the calcium comes in contact with inorganic phosphates liberated from organic phosphates under enzymic influence. Thus calcium phosphate is formed and used by the osteoblasts to make new bone.

image by pt02n

Rickets is the disease caused by the deficiency of vitamin D occurring especially in infancy and childhood. It is caused by the deficiency of vitamin D leading to an insufficiency of calcium in the body.  The absorption of calcium from the gut is impaired. The diet is also usually poor in absorbable calcium. Lack of calcium affects the nerves and muscles, and especially bones  with disturbance of normal ossification, marked by bending and distortion of the bones, nodular enlargements on the ends and sides of the bones, delayed closure of the fontanel’s, muscle pain and sweating of the head.

Although rickets was described in ancient times, it was not well known until the seventeenth century.  Rickets has been characteristically a disease of the poor rather than the rich. Milk and cream, butter and eggs, the only common foods providing a satisfactory dietary source of vitamin D, may be too expensive for poor urban families. A plentiful supply of cereals provides calories which may enable growth to take place at a faster rate than the skeleton can be properly formed if calcium absorption is inadequate.

image by XODÓ DI PANO / YO-YO CRAFT

In the last thirty years rickets has virtually disappeared from most of the countries in the universe and it a truth that every one now knows is that milk is the important source for preventing rickets. Every country is having many schemes to feed their children with sufficient milk which is the main source for the vitamin D and several countries take much attention to have sufficient sunlight for every house buildings for their people.

Pathologically it is described that due to deficiency of vitamin D the calcium absorption is affected and hence the level of calcium in the serum is lowered and it causes tetany.

Clinically it is explained that infant with rickets has often received sufficient calories and may appear well nourished, but he/she is restless, pale, with flabby and toneless muscles. Excessive sweating of the head is common.  The abdomen is distended and it may arise from the excessive carbohydrate in the diet.

Gastrointestinal upsets with diarrhea are common. The infant is prone to respiratory infections. Development is delayed so that the teeth erupt late and there is failure to sit up, stand, crawl and walk at the normal ages.

image by Chris Nixon

The bony changes are the most characteristic and easily identifiable signs of rickets. There is extension and widening of the epiphyses at the growing points, where cartilage meets bone. Craniotabes usually disappear after six months, but later there may be bossing of the frontal and parietal bones and delayed closure of the anterior fontanalle. Later too, there may be deformities of the chest such as pigeon chest appears. If rickets continue, when the rachitic child begins to walk, she may have the knock knees or bow legs. Pelvic deformities may also develop when the child grows.

If a child is affected by rickets two essential things are to be followed with the guidelines of general practitioners and they are adequate intake of vitamin D and calcium. Apart from this that the child has to be allowed to have sufficient sunshine and this will cure the disease.

Osteomalacia is a disease which means softening of bones due to deficiency of calcium or vitamin D or both.

Osteoporosis, which is an atrophy of bone, is believed to be due to the defective formation of bone matrix which is due to the deficiency of vitamin D or calcium or both.

Both Osteomalacia and Osteoporosis should be treated with adequate vitamin D and calcium necessarily with hormones.

Prevention of the rickets: the natural means of prevention is regular exposure to the sun’s UV light and there appears to be enough vitamin D in breast milk and in modern milk based formulas. Cod liver oil is still effective but unpopular because of its taste.

General dietary sources of vitamin D

1. fish liver oil
2. Fortified margarine.
3. infant milk formulas
4. Eggs, liver.

Related posts:

1. The Role of Vitamin D in the Human Body
2. How Calcium Makes Our Bones Strong
3. CF patients need more vitamin D than current recommendation
4. Vitamin B Complex
5. Vitamin E Deficiency Syndromes