DISORDERS DUE TO NUTRITIONAL DEFICIENCY I
Vitamins:- Organic substances which cannot be synthesized by the body and are
essential for maintenance of normal structure and function of cells.
➔Fat soluble vitamins (ADEK):- Absorbed from intestine in the presence
of bile salts
Excess vit A and D can lead to hypervitaminosis
➔Water soluble vitamins (C & B complex) :- readily absorbed from the
small intestine . These vitamins are easily lost due to cooking or
processing of food.
❖Vitamin A ( Retinol):-
Retinol is stored in liver→released→bind to retinol binding protein in blood
→transported
The physiologic functions of retinol is :
1. Maintenance of normal vision of light. This involves 2 pigments by
oxidation of retinol :
a. Rhodospin ……… light sensitive pigment in reduced light
synthesized in rod cells
b. Iodospins…….sensitive in bright light and formed in cone cells of
retina
2. Maintenance of normal cartilaginous and bone growth
3. Anti proliferative effect. β -carotene (a form of vit A) has an antioxidant
properties and may cause regression of certain precancer conditions and
certain cancer
Vitamin A deficiency pathologic changes:-
● Night blindness results due to metaplasia of mucus secreting cells by
squamous cells. There is dry and scaly scleral conjunctiva
(xerophthalmia).
○ Corneal ulcers may occur which may get infected and cause
keratomalcia.
○ Bitot spots may appear which are focal triangular areas of opacities
due to accumulation of keratinised epithelium
, ● Other lesions:-
○ Squamous metaplasia of respiratory epithelium of bronchus and
trachea which may result in respiratory infections
○ Squamous metaplasia of pancreatic ductal epithelium
Hypervitaminosis A :- very large doses of vitamin A can produce toxic
manifestations in children as well as adults. These may be acute or chronic
1. Acute toxicity : effects included are neurological and resembles brain
tumor e.g headache , vomiting etc…
2. Chronic toxicity
a. Neurological such as headache and disordered blurred vision due to
increased intracranial pressure
b. Skeletal pains due to loss of cortical bone by increased osteoclastic
activity
c. Cutaneous involvement may be in the form of fissuring,peeling of
skin and coarseness of hair
d. hypercarotenemia is yellowness of palms and skins
Oral manifestations of vitamin A deficiency:
Oral keratotic changes and disorders of mucosal keratinization as well as
enamel and dentin anomalies
xerostomia , the subjective sensation of a dry mouth-salivary hypofunction
secondary to keratinization of minor and major salivary gland , accessory glands
of the tongue and blockage of salivary out flow
❖Vitamin D (calcitriol)
This is a fat soluble vitamin and exits in 2 activated forms:
➔Vitamin D2 or calciferol
➔Vitamin D3 or cholecalciferol
These are the main sources of vitamin D :
i) Endogenous synthesis :- 80% of body’s need of vitamin D is met by
endogenous synthesis from the action of UV light on 7-dehydrocholesterol
widely distributed in oily skin secretions of the skin. The vitamin so formed by
irradiation enters the body directly through skin
Vitamins:- Organic substances which cannot be synthesized by the body and are
essential for maintenance of normal structure and function of cells.
➔Fat soluble vitamins (ADEK):- Absorbed from intestine in the presence
of bile salts
Excess vit A and D can lead to hypervitaminosis
➔Water soluble vitamins (C & B complex) :- readily absorbed from the
small intestine . These vitamins are easily lost due to cooking or
processing of food.
❖Vitamin A ( Retinol):-
Retinol is stored in liver→released→bind to retinol binding protein in blood
→transported
The physiologic functions of retinol is :
1. Maintenance of normal vision of light. This involves 2 pigments by
oxidation of retinol :
a. Rhodospin ……… light sensitive pigment in reduced light
synthesized in rod cells
b. Iodospins…….sensitive in bright light and formed in cone cells of
retina
2. Maintenance of normal cartilaginous and bone growth
3. Anti proliferative effect. β -carotene (a form of vit A) has an antioxidant
properties and may cause regression of certain precancer conditions and
certain cancer
Vitamin A deficiency pathologic changes:-
● Night blindness results due to metaplasia of mucus secreting cells by
squamous cells. There is dry and scaly scleral conjunctiva
(xerophthalmia).
○ Corneal ulcers may occur which may get infected and cause
keratomalcia.
○ Bitot spots may appear which are focal triangular areas of opacities
due to accumulation of keratinised epithelium
, ● Other lesions:-
○ Squamous metaplasia of respiratory epithelium of bronchus and
trachea which may result in respiratory infections
○ Squamous metaplasia of pancreatic ductal epithelium
Hypervitaminosis A :- very large doses of vitamin A can produce toxic
manifestations in children as well as adults. These may be acute or chronic
1. Acute toxicity : effects included are neurological and resembles brain
tumor e.g headache , vomiting etc…
2. Chronic toxicity
a. Neurological such as headache and disordered blurred vision due to
increased intracranial pressure
b. Skeletal pains due to loss of cortical bone by increased osteoclastic
activity
c. Cutaneous involvement may be in the form of fissuring,peeling of
skin and coarseness of hair
d. hypercarotenemia is yellowness of palms and skins
Oral manifestations of vitamin A deficiency:
Oral keratotic changes and disorders of mucosal keratinization as well as
enamel and dentin anomalies
xerostomia , the subjective sensation of a dry mouth-salivary hypofunction
secondary to keratinization of minor and major salivary gland , accessory glands
of the tongue and blockage of salivary out flow
❖Vitamin D (calcitriol)
This is a fat soluble vitamin and exits in 2 activated forms:
➔Vitamin D2 or calciferol
➔Vitamin D3 or cholecalciferol
These are the main sources of vitamin D :
i) Endogenous synthesis :- 80% of body’s need of vitamin D is met by
endogenous synthesis from the action of UV light on 7-dehydrocholesterol
widely distributed in oily skin secretions of the skin. The vitamin so formed by
irradiation enters the body directly through skin
