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Zinc is an essential mineral needed in the diet on a daily basis. It is a micro mineral needed in very small amounts, but is vital for the healthy working of many systems of the body. Zinc is present in every part of the body, most of it being in the muscles, followed by bones and skin.

[edit] Functions

Zinc performs a wide range of functions in the human body as it is a cofactor for a number of enzymes. It is a regulator of genetic activities and is needed for DNA (deoxyribonucleic acid) synthesis. It supports the immune function and is essential for taste and smell sensitivity.

Zinc plays an important role in cell division, cell growth, wound healing, reproduction and neurological function. It is essential for protein synthesis, bone mineralization, proper thyroid function and blood clotting. It also supports normal growth and development during pregnancy, childhood, and adolescence.

[edit] Food Sources

Zinc is present in both animal and plant foods. Zinc from animal foods such as meat, eggs and seafood is better retained in the body as compared to plant sources, as the high content of phytic acid in plant foods inhibits zinc absorption. Other good sources of dietary zinc include oysters, nuts and legumes, whole grains and beans.

Losses of zinc on cooking and processing are related to the form in which zinc is present in foods. When present in a water soluble form predominantly, losses can be appreciable. Processing of wheat also leads to a high loss of the original zinc present.

[edit] Recommendations

The Recommended Dietary Allowances for zinc on a daily basis, set in 1999 by the Institute of Medicine at the National Academy of Sciences, are as follows:

  • Males and females, 1-3 years: 3 milligrams
  • Males and females, 4-8 years: 5 milligrams
  • Males and females, 9-13 years: 8 milligrams
  • Males 14 years and older: 11 milligrams
  • Females 14-18 years: 9 milligrams
  • Females 19 years and older: 8 milligrams
  • Pregnant females 18 years or younger: 12 milligrams
  • Pregnant females 19 years and older: 11 milligrams
  • Lactating females 18 years or younger: 13 milligrams
  • Lactating females 19 years and older: 12 milligrams

Refer to The World's Healthiest Foods

[edit] Deficiency

Zinc deficiency occurs when there are increased losses or decreased absorption of zinc. The individuals at risk for zinc deficiency include infants and children, pregnant and lactating women, malnourished individuals, strict vegetarians and those with absorption problems. The symptoms of zinc deficiency include depression, lack of appetite, slow growth in children, frequent colds and infections, hair loss, delayed sexual maturation and impotence, skin lesions, glucose intolerance, and problems with sense of taste and smell.

[edit] Toxicity

Increased intake of zinc over a long period of time can lead to zinc toxicity. The symptoms include stomach pain, abdominal cramps, nausea, vomiting, diarrhea, drowsiness and dizziness. A metallic, bitter taste in the mouth can be indicative of zinc toxicity. The U.S. Food and Nutrition Board has set the tolerable upper level of intake (UL) for adults at 40 mg/day, including dietary and supplemental zinc.

[edit] References

  • Zinc: What is it?
  • Vegetarian Information Sheet
  • Zinc in diet
  • Zinc trace element information page
  • Zinc