This document summarizes information about zinc, including its history of being recognized as an essential element, importance for growth, typical dietary sources, absorption and transport in the body, signs of deficiency, and treatment of deficiency. It notes that zinc is essential for growth, plays many roles in the body, and deficiency can cause issues like stunted growth, hypogonadism, and skin lesions. The primary causes of deficiency are listed as malnutrition, alcoholism, malabsorption, and certain diseases.

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.