Vitamin A – This book covers the entire syllabus of “Nutrition and Dietetics” prescribed by BNMC-for all Diploma in Nursing Science and Midwifery students. We tried to accommodate latest information and topics. This book is examination friendly setup according to the teachers’ lectures and examination’s questions. At the end of the book previous university questions are given. We hope in touch with the book students’ knowledge will be upgraded and flourished. The unique way of presentation may make your reading of the book a pleasurable experience.

Table of Contents

Vitamin A

Vitamin-A is a fat soluble vitamin which covers both a preformed vitamin, retinal, and a pro-vitamin, beta carotene, some of which is converted to retinal in the intestinal mucosa.

(Ref: K. Park/24/656)

Vitamin-A is necessary for growth and level it raises the general of resistance against infection. It is therefore called growth promoting and anti-infective vitamin.

Source of Vitamin-A:

1. Animal source:	Liver. Mola, dhela (small fish) & other small fishes. Milk, butter, cheese. Egg yolk. Fish liver oil (cod liver oil)
2. Vegetable sources (B-carotene):	Carrot (richest source of carotene). Dark green leafy vegetables such as- sphinach, kachu, sajna, datashak, kalmi, thankune, cabbage etc. Some yellow & red fruits (apricots, melon, pumpkin)
3. Fortified foods:	Vanaspati. Margarine Milk.

(Ref by: T. K. Indrani/1/74-75)

Function of vitamin-A:

It is essential for normal vision. It contributes to the production of retinal pigments, which are needed for vision in dim light.
It is necessary for maintaining the integrity and the normal functioning of glandular and epithelial tissue, which lines intestinal, respiratory and urinary tracts as well as the skin and eyes.
It supports growth especially skeletal growth.
It is anti-infective: there is increased susceptibility to infection and lowered immune response in vitamin-A deficiency, and
It may protect against some epithelial cancers such as bronchial cancers.
It is essential for the formation of teeth.
It is essential to maintain normal reproductive function in males.

Ref: T. K. Indrani/1″/29)

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Effects of vitamin-A deficiency:

Two types of effect

Ocular
Extra ocular

1. Ocular effects:

a) Night blindness:

Vitamin-A deficiency first causes inability to see in dim light especially in late evenings.

b) Conjunctival xerosis: –

Conjunctiva becomes dry and nonwetable.
Instead of looking smooth and shiny, it appears muddy and wrinkled.

c) Bitot’s spot:

Triangular, pearly-white or yellowish, foamy spots on the bulbar conjunctiva on either side of the cornea.

d) Corneal xerosis: cim

Serious stage.
Cornea appears dull, dry and non-wettable and eventually opaque,
In more severe deficiency; there may be corneal ulceration.

e) Keratomalacia:

Liquefaction of cornea sin tuoda rinde ni str
Part or whole of the cornea may become soft & may burst open.
If the eye collapses, vision is lost.

2. Extra-ocular manifestation of vitamin-A-vitamin deficiency:

Follicular hyperkeratosis (Phrynoderma)
Anorexia.
Growth retardation.
Respiratory & intestinal infection.

Daily requirement of vitamin-A:

Vitamins

Age group

RDA.

Vitamin-A

Adult

“Man
Woman
Pregnant
Lactation

Infants

0 to 12 months

Children

1 to 6 years
7 to 12 years

Adolescent

13 to 19 years”

Retinol (µg)

B-carotene (µg)

600
600
600
750350400
600

600

2400
2400
2400
3800

1200

1600
2400

2400

(Ref by: K. Park/24/666)

Vitamin A is needed because –

1. To keep the eye healthy. Vitamin A keeps the front of the eye (the conjunctiva and cornea) strong, clear, and wet. It helps the eye to see in dim light.

2. To help children to grow properly

3. To prevent infections

4. Vitamin A destroys free radicals and so helps to prevent tissue damage during infection.

Unit:

Retinol equivalent (RE)

The conversion can be done in the following way:

1 mcg of retinol = 1 mcg of RE
1 mcg of beta carotene = 0.167 mcg of RE
I mcg of other carotenoids 0.084 of RE

Absorption and storage of vitamin A:

Vitamin A is absorbed in the small intestine and pass along with fate through the lymphatic system into the blood stream, form blood stream liver can store large amount of vitamin A, when fed on diet rich in vitamin A.

The liver has an enormous capacity for storing vitamin A, mostly in the form of retinol palmitate.

A well-fed person has sufficient vitamin-A reserves to meet his needs for 6 to 9 months or more. In severe protein deficiency, decreased production of retinol-binding protein prevents mobilization of liver retinol reserves.

(Ref: T. K. Indrani/1/76)

Symptoms of toxicity of vitamin A:

Excessive intakes of vitamin-A are toxic to both children and adults.

1. Hyperirritability.

2. Drying of skin

3. Desquamation of the skin.

4. Loss of hair.

5. Headaches.

6. Enlargement of liver and spleen.

Prevention and Control of Night Blindness:

Health promotion:	Promotion of breast feeding. Improvement of environmental health. Better feeding of infants & young children Health education. High potency vitamin A for risk group.
Specific protection:	Diet must contain adequate vitamin A Immunization. Food fortification
Early diagnosis & Treatment:	Periodic surveillance. Early diagnoses & treatment of night blindness. Development of programme – ✓ Distribution of food ✓ Supplementary feeding. Treatment of infection & worm infestation.
Treatment of night blindness:	For children over 1 year and under 6 years old Immediately on diagnosis -200000 LU. Vit-A-orally The following day/next day-200000 IU. Vit-A-orally dom After 14 days 200000 LU. Vit-A-orally

Measures to Prevent Vitamin A Deficiency:

1. Periodic administration of high-doses of vitamin A (2,00000 IU) is an effective measure of controlling vitamin A deficiency.

2. Adequate treatment and supplementation for mal-nutrition, diarrhea infection and, measles.

3. Long term measures including nutrition education such as local sources of the vitamin A or carotenoids, production and consumption of foods rich in vitamin A or pro-vitamin A and fortification of foods with vitamin A.

4. Programs to encourage breast feeding increased consumption of dark green leafy vegetables, carrot, egg, liver, fish and meal cod liver oil, small fish etc, can be provided when parents can afford

Read more:

Fat Soluble Vitamin | CHAPTER 1 | Nutrition and Dietetics

Vitamin A | CHAPTER 1 | Nutrition and Dietetics