ZINC

Reading Time: 3 minutes

Zinc is a mineral. It is an essential trace element as very small amounts of zinc are necessary for the human body. The human body cannot store excess zinc hence, it must be consumed regularly as part of the daily diet.

Why is Zinc essential for the body?

Zinc is the most abundant intracellular trace element. It has been estimated that a newborn child contains approximately 60 mg of zinc. During growth and maturation, the zinc concentration of the human body increases to approximately 30 mcg. The adult total body zinc content ranges from about 1.5 g in women to 2.5 g in men. 

Wound Healing:

Zinc plays an important role in cell multiplication and cell growth. Hence reduced cell replication is an early sign of zinc deficiency. Zinc deficiencies in children are usually marked by poor growth and impairment of sexual development. Mild zinc deficiency may also affect the quality of growth. In both, children and adults, zinc deficiencies result in poor wound healing. 

Sense of taste:

Zinc is present in gustin (a salivary polypeptide that appears to be necessary for the normal development of taste buds). Thus zinc deficiency also leads to a decreased sense of taste.

Immunity:

Zinc is found in cells throughout the body. It helps the immune system fight off invading bacteria and viruses.

Hair Care:

Zinc can play a key role in making proteins for the hair. The body can’t make it, so you need to get it from food or supplements. Signs of low zinc levels include hair loss.

How much Zinc do we need?

Men: 12 mg/day

Women: 10 mg/day

Pregnancy and Lactation: 12 mg/day

Children 

1 to 3 years: 5mg/day

4 to 9 years: 8mg/day

10 to 12 years: 9 mg/day

13 t0 15 years: 11 mg/day

16 to 18 years: 12 mg/day

What are the signs and symptoms of zinc deficiency?

The clinical features of severe zinc deficiency in humans are :

· growth retardation

· delayed sexual and bone maturation

· skin lesions

· diarrhea

· alopecia (loss of hair or baldness)

· impaired appetite

· increased susceptibility to infections mediated via defects in the immune system

· appearance of behavioral changes (depression or mood changes) 

What are the food sources of zinc?

Zinc is normally associated with the protein and nucleic acid fraction of foods. Therefore, foods high in proteins are usually good sources of zinc.

Plant sources: Sesame or gingelly seeds, Cashew nuts, almonds, whole grain cereals, pulses, and legumes, 

Animal sources: Oysters, shrimp, lean red meat, chicken, beef, pork, eggs, and milk.

Processed cereals with low extraction rates, polished rice, and chicken, pork, or meat with high-fat content have moderate zinc content. Fish, roots and tubers, green leafy vegetables, and fruits are only modest sources of zinc whereas, saturated fats and oils, sugar, and alcohol have very low zinc contents.

Can excess Zinc cause toxicity?

Gross acute zinc toxicity has been reported after consuming water stored in galvanized containers. The toxicity signs are nausea, vomiting, diarrhea, fever, and lethargy and have been observed after ingestion of 4-8 g of zinc.

Long-term zinc intakes higher than requirements could, however, interact with the metabolism of other trace elements but do not cause toxicity.

Intakes between 25 -50 mg zinc per day have been reported to interfere with the metabolism of both iron and copper. WHO has, therefore, recommended the upper level of zinc intake for an adult man at 45 mg/day.

The central role of zinc in cell division, protein synthesis, and growth is especially important for infants, children, adolescents, and pregnant women; these groups suffer most from an inadequate zinc intake.

Most people meet the daily requirement of zinc by incorporating a variety of protein-rich foods into their diet.

Plenty of zinc supplements are available for those with severe zinc deficiency or chronic illness. Consult a doctor before taking any zinc supplements as high doses of zinc through supplements could lead to toxic effects on the body.