ZINC METABOLISM

1. Zinc Metabolism
Gandham.Rajeev

2. • Zinc is a trace mineral.
• Total body content of zinc is about 2 gm.
• Prostate gland is very rich in Zn (100 mg/g).
• Zn is mainly an intracellular element.
• About 60% of zinc is present in muscle and 30%
in bone.
• It is also present in liver, brain and skin.

3. • Sources:
• Animal sources are meat, liver, milk and
dairy products.
• Vegetables sources are legumes, pulses, nuts,
beans & spinach.
• The colostrum is an especially rich source.
• RDA:
• Adults: 15 mg/day.
• Pregnant women: 15-20 mg/day.

4. • Zn is mainly absorbed from duodenum.
• Zn from animal sources is better absorbed
than vegetable sources.
• It requires a transport protein – matallo-
thionein.
• Phytate, Ca2+, copper & decreases absorption.
• Small peptides & amino acids promotes
absorption.
Absorption

5. Functions
• Zinc is component of many metalloenzymes.
• Ex:
• Red blood cell carbonic anhydrase
• Alkaline phosphatase, alcohol
dehydrogenase, carboxy-peptidase, SOD
(cytosol)
• Many enzymes involved in RNA and DNA
synthesis, such as DNA and RNA polymerases

6. • Zn may be regarded as antioxidant, SOD
protects the body against free radicals.
• Storage & secretion of insulin from β- cells of
pancreas requires Zn.
• Zn necessary to maintain normal levels of
vitamin A.
• Zn is required for synthesis of RBP.

7. • Zinc is an important element in wound
healing.
• Zn is necessary for growth & division of cells.
• Zn stabilizes membrane structure.
• Gusten, a zinc containing of the saliva, is
important for taste sensation.
• Zinc stabilizes the structure of protein & nucleic
acids.
• Zn is essential for proper reproduction.

8. Deficiency
• Causes:
• Dietary deficiency, malabsorption including
inherited defect in zinc absorption, chronic
alcoholism, nephrotic syndrome, parental
nutrition with inadequate zinc.
• Clinical symptoms:
• Hypogonadism (impaired spermatogenesis)

9. • Growth failure
• Loss of taste sensation
• Impaired wound healing
• Skin lesions such as dermatitis
• Acrodermatitis enteropathica:
• A rare inherited metabolic disease of zinc
deficiency.
• Caused by defective absorption of Zn in the
intestine.

10. Zinc toxicity
• Zinc toxicity is rare.
• Zinc toxicity is seen in welders due to
inhalation of zinc oxide fumes.
• Clinical features:
• Nausea, gastric ulcer, pancreatitis, diarrhea,
anemia, excessive salivation, vomiting,
stomach cramps.

11. Reference books
• Text book of Biochemistry - U Satyanarayana
• Text book of Biochemistry – DM Vasudevan
• Text book of Biochemistry - MN Chatterjea

12. Thank You