2.  1509, recognized as element
 Essentiality demonstrated
 Plants: 1869
 Animals: 1934
 Deficiency
 Considered unlikely until 1955
 conditioned human deficiency demonstrated in 1956
 1961, hypogonadal dwarfism suggested to be zinc
deficiency

3.  Relatively abundant mineral
 Good sources: shellfish, beef and other red meats
 Slightly less good: Whole-grains
 most in bran and germ portions
 80% lost to milling
 phytates, hexa & penta phosphates depress absorption
 P/Zn ratios of 10 or more
 Relatively good sources: nuts and legumes
 Eggs, milk, poultry & fish diets lower than
pork, beef, lamb diets
 High meat diets enhance absorption
 280g or 10 oz fits right into food pyramid guide
 cys & met form stable chelate complexes

4.  Zinc absorption is greater from a diet high in
animal protein than a diet rich in plant proteins
. Phytates, which are found in whole grain
breads, cereals, legumes and other products,
can decrease zinc absorption .

5.  Whole body: 1.5g (female)-2.5g (male)
 Skeletal Muscle 57%
 Bone 29%
 Skin 6%
 Liver 5%
 Brain 1.5%
 Kidneys 0.7%
 Heart 0.4%
 Hair ~0.1%
 Blood Plasma ~0.1

6. Foods contain element zinc, much
of it bound to protein or DNA.
 Oysters (> 70 mg per
serving).
 Meats (2-3 mg/100g).
 Shellfish (2.7 mg/100g)
 Other good food sources
include:
 beans, nuts, certain seafood,
whole grains, fortified
breakfast cereals, and dairy
products .

7.  Required for growth in children and infants.

8.  GIT modulates the quantity of exogenous
dietary zinc absorbed and the quantity of
endogenous zinc excreted
 More than 70% of a small zinc dose (less than 3
mg) is absorbed from the small intestine.
 Maximum absorption occurs in duodenum
 There is sustained release from enterocytes into
portal circulation for ~ 9h

9.  Zinc absorption mainly achieved by 2 families
of zinc transporters;
1. ZIP Family
2. ZnT Family

10.  Routes: intestine, kidneys, integument, and semen
 After a meal, maximum zinc secretion occurs through
pancreatobiliary secretions
 Maximum reabsorption occurs from mid-jejunum and
ileum
 Total amount excreted = Amount secreted – Amount
reabsorbed
 Excretion of endogenous zinc by the intestine depends
on the ‘zinc status’ of the body.

11.  Causes;
 Malnutrition
 Alcoholism
 Malabsorption
 Burns
 Chronic renal disease
 Acrodermatitis enteropathica

12.  Signs
 Growth retardation
 Delayed sexual maturation & impotence
 Impaired testicular development
 Hypogonadism & hypospermia
 Alopecia
 Acroorifical skin lesions
 Other, glossitis, alopecia & nail dystrophy
 Immune deficiencies
 Behavioral changes

13.  Night blindness
 Impaired taste (hypoguesia)
 Delayed healing of wounds, burns, decubitus ulcers
 Impaired appetite & food intake
 Eye lesions including photophobia & lack of dark
adaptation

14. 1. Severe
 dermatitis, alopecia, diarrhea, emotional disorder,
weight loss, infections, hypogonadism in males
2. Moderate
 growth retardation and delayed puberty in
adolescents, hypogonadism in males, rough skin,
poor appetite, mental lethargy, delayed wound
healing, taste abnormalities and abnormal dark
adaptation
3. Mild
 oligospermia, slight weight loss and
hyperammonaemia

15.  Zn deficient rats failed to conceive
 Abnormalities of blastocyst development
 Offspring had high incidence of abnormalities
 Deformities of brain, skull, limbs, eyes, heart, lungs
 Low Zn intake during the third trimester may
not have such profound effects
 Main stages of differentiation are already complete
 Can result in low birth weight, and prolonged and
difficult parturition

17.  Excess accumulation within cells may disrupt
functions of biological molecules
 Protein, enzymes, DNA
 Leads to toxic consequences
 Anemia
 Impaired copper availability
 Acute excessive intakes
 Local irritant to tissues and membranes
 GI distress, nausea, vomiting, abdominal cramps, diarrhea
 Relatively non-toxic
 Sources of exposure – drinking water, feed, polluted air

18.  Genetic disorder of zinc absorption.
 Presents during infancy.
 Characterized mainly by a triad consisting of
1. Acral dermatitis
2. Alopecia
3. diarrhea

19.  In infants bottle fed with bovine milk, days to
week, breast fed infants soon after feeding
 In older children its acquired zinc deficiency.

20.  Acrodermatitis enteropathica; autosomal
recessive trait resulting in failure to absorb
zinc.
 Acquired zinc deficiency; secondary to reduced
dietary intake , malabsorption, increased
urinary loss, etc.

21.  Skin mucous membrane and hair are involved.
 Lesions are pink and later become brightly
erythematous.
 Impaired wound healing.
 Irritable with depressed mood
 Growth failure

22.  Loss of weight
 Sensitivity to light
 Diarrhea
 Conjuctivitis
 Red glossy tongue and mouth ulcers

27.  Complete blood count
 Serum/ plasma zinc levels
 Urine; zinc excretion is reduced
 Dermatopathology; intraepidermal clefts and
blisters

28.  1mg/kg body weight of oral zinc
supplementation per day of life.
 Zinc gluconate better tolerated than sulfate.
 Dietary or iv supplementation with zinc salts
with two or three times , the RDA restores
normal zinc status in days or week.

31.  All children above 6months should receive a
uniform dose of 20mg elemental zinc as soon as
diarrhoea starts and continue for 14 days.
 2 to 6mnths- 10mg/day for 14 days.