Wednesday, 24 October 2018

Meaning, Functions, Effects and Sources of Vitamin D

Vitamins are a type of organic compounds which are essential for growth and maintenance of good health.These are required in very small amounts but our body cannot synthesise most of them.Hence intake of vitamins in food is essential.Deficiency of vitamins leads to many deficiency diseases.Vitamins are regulatory substances and each vitamin has a specific function.These are also known as life saving substances. So in this we are going to talk about Meaning, Functions, Effects and Sources of Vitamin D.


Meaning, Functions, Effects and Sources of Vitamin D


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Meaning of Vitamin D

Vitamin D is second important fat soluble vitamin. It is essential for the growth of our body. It is also known as calciferol. Vitamin D is present in our skin as a precursor in the form of ergosterol and 7-de-hydrocholesterol. These precursors are converted into vitamin D in the presence of ultra-violet rays of the Sun. Vitamin D is also known as anti ricketic factor.

Functions of Vitamin D

Following are the funtions of Vitamin D are as fallow:

(a) Formation of bones and teeth

Vitamin D along with calcium and phosphorus forms bones and teeth. Deposition of calcium-phosphate in bones and teeth makes them healthy and strong. That is why it is also known as calcifying vitamin.

(b) Absorption of calcium and phosphorus.

Vitamin D is an essential substance in the absorption and utilisation of calcium and phosphorus.
(c) Vitamin D regulates the amount of calcium and phosphorus in blood. For this it reabsorbs phosphorus in kidney.

Effects of deficiency of vitamin D

(a) Deficiency of vitamin D causes Rickets in children with the following symptoms
(i) Growth of bones is retarded. These become soft and fragile and hence bends easily by the weight of the body, leading to a state called 'Knock Knees'.
(ii) The ends of long bones enlarges due to improper calcification. Head is enlarged and forehead bulges out. Ribs become hollow and bulge out resembling pigeon's chest. This is known as 'Pigeon's Chest'.
(iii) Pot belly in children.
(iv) Small height in children.
(v) Defective teeth.
(vi) Irritability, disinclination towards play, insufficient sleep, more appetite and convulsions.
(b) Deficiency of vitamin D in adults causes Osteomalacia in it.
(i) Bones become soft and fragile and more prone to multiple fractures.
(i) Pain in lower part of the back and thighs. Back bone bends causing back hunch.
(iii) Disorder of Reproductive organs in women with a possibility of abortion.
(c) Low serum calcium level because of deficiency of vitamin D causes 'Tetany'. It causes trembling in hands and sometimes cramps and convulsions in children.

Effects of excess of vitamin D

Continuous excessive intake of vitamin D have toxic effect in the body. Increased calcium and phosphorus level in blood causes calcification in tissues around delicate organs, arteries, etc. Symptoms of nausea, vomiting, diarrhoea, polyurea, polyphagia, sweatirg appears. Blood pressure also increases.

Sources of vitamin D

Following are the Sources of Vitamin D are as fallow:

(a) From sunlight

Precursors of vitamin D in the outer layer of skin are converted into vitamin D in the presence of ultra-violet rays of the sun. Hence, in tropical countries like India sunrays are the main source of vitamin D.

(b) From food products

Vitamin D is present only in foods of animal kingdom. For example, cod liver oil, egg yolk, butter, cheese, whole meat, etc. are good sources of vitamin D

Daily recommendation.

India being a tropical country ICMR has recommended 2000 I.U. (International Units) of vitamin D for all age groups.

So these are the Meaning, Functions, Effects and Sources of Vitamin D.

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