11 zinc

Zinc

Introduction• Zinc is an essential constituent of

metallo-enzymes• Plays a major role as stabilizer of the

molecular structure of sub-cellularmolecular structure of sub-cellularconstituents and membranes

• Involved in synthesis & degradationof MN & nucleic acids

• Has important role in polynucleotidetranscription and translation (in theprocess of genetic expression)

Cont…

• Practically found in every cell of the body and is a part of over 200 enzymes which probably makes zinc essential for all forms of life essential for all forms of life

• It is important for the maintenance of vision, taste and smell & also necessary for immune function

Cont…

• It is required for the activity of theantioxidant enzyme superoxidedismutase.

• Zinc has been used successfully in• Zinc has been used successfully inthe treatment of rheumatoidarthritis, acne macular (eye)degeneration and recently in thetreatment of diarrheas

Cont…

• Studies have shown that Zinc supplements have led to the improvements in memory, comprehension, communication, and social interaction among patients social interaction among patients with abnormal eating behavior, and AIDS patients. Several endogenous factors are thought to serve as ligands, with zinc enhancing its absorption

Sources

Dietary sources of zinc are:protein rich foods,

– including meat,– fish,– shellfish and– shellfish and– whole grains.

Root and tuber crops are low in zinccontent,

while zinc in cereal staples is most oftenpoorly bio-available.

Factors affecting absorptionEnhancers Inhibitors

Citric acid,Nicotinic acid (tryptophanmetabolite)Histidine

Iron,Phytic acid,Polyphenols or(tryptophanmetabolite)

HistidineCysteineRiboflavin

Polyphenols orExcessive dietary fibre

Functions

• Antioxidant• Maintains normal taste and smell• Promotes normal growth and development• Aids wound healing• Promotes normal fetal growth• Promotes normal fetal growth• Helps in the synthesis of DNA and RNA• Promotes cell division, cell repair, cell growth• Maintains normal level of vitamin A in blood• It is also part of the molecular structure of 80

or more known enzymes, which work with red blood cells to shift carbon dioxide from tissues to lungs

Consequences

While severe ZnD are uncommon, marginaldeficiencies are frequently seen in children,elderly and among patients suffering fromabnormal eating behavior, and AIDS patients:

• Impaired immune functionImpaired GI function• Impaired GI function

• Impaired growth & development• Increased vulnerability to infection• Decreased host resistance• Increased morbidity & mortality (acute andpersistent child diarrhea, ARI especiallypneumonia)

Zinc status globally

• The first cases of zinc deficiency in humanswere described in 1963 in male dwarfs fromthe Middle East

• In north America and NewZealand , overtand severe nutritional ZND was recognizedin patients receiving parenteral nutrition orenteral feedingin patients receiving parenteral nutrition orenteral feeding

• To date, WHO research has identified ZNDas among the major risks to child health,linked with 10% of diarrhea morbidity, 6%of lower respiratory tract infection morbidityand 18% of malaria morbidity andaccounting for 800,000 child deaths peryear across the world (mainly developingcountries)

Zinc status in Ethiopia

• The prevalence of ZND in Ethiopia is unknown,but mild to moderate forms of the deficiency arelikely to be present particularly where theprevalence of stunting in the country is high.

• A recent double blind randomised controlledstudy in Arsi area indicated the presence of ZNDin areas where the staple diet is cereal based.The clinical trial significantly increased thein areas where the staple diet is cereal based.

• The clinical trial significantly increased thegrowth rate of stunted children in rural Ethiopia.

• This finding underlines the need for zincsupplementation in high risk areas.

• Besides correcting the stunting process ininfants, zinc supplementation was shown to beessential for improving general health status,stimulating appetite and reducing morbidity dueto several infantile diseases

Cont…

• In most of the rural parts of Ethiopia, consumption of animal sources is mostly limited to occasional public holidays indicating that the intake of the nutrient is minimal. In view of this, one can expect a high prevalence of the nutrient is minimal. In view of this, one can expect a high prevalence of zinc deficiency in Ethiopia. This might be a factor in the high prevalence of stunting is high although further studies are called for to clarify this relationship.

Lab Tests to DetectDeficiency

• Serum/plasma zinc concentration• Erythrocyte zinc concentration• Urine zinc concentration• Hair zinc concentration• Hair zinc concentration• Salivary zinc concentration• Oral zinc tolerance test• Taste acuity tastes• Zinc dependent enzymes (alkaline

phosphates and carboxypeptidase)

RDA

Control and Prevention

• Food fortification• Daily/weekly supplementation• Education

FMoH is introducing the product into the FMoH is introducing the product into the public sector, and with advocacy support from PSI/Ethiopia, is now including zinc in its national essential drug lists, into guidelines for the integrated management of childhood illnesses, and into its nutrition guidelines