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* जिंक metal is included in most single tablet over-the-counter daily vitamin and mineral supplements. It is believed to possess anti-oxidant properties, which protect against premature aging of the skin and muscles of the body. In larger amounts, taken as जिंक alone in other proprietaries, it is believed by some to speed up the healing process after an injury. Preparations include [[जिंक acetate]] and [[जिंक gluconate]].
* [[जिंक gluconate glycine]] and [[जिंक acetate]] are also used in [[throat lozenge]]s or [[tablet]]s to reduce the duration and the severity of cold symptoms.<ref>Ananda S. Prasad, MD, PhD; James T. Fitzgerald, PhD; Bin Bao, MD, PhD; Frances W.J. Beck, PhD; and Pranatharthi H. Chandrasekar, MD. "Duration of Symptoms and Plasma Cytokine Levels in Patients with the Common Cold Treated with जिंक Acetate: A Randomized, Double-Blind, Placebo-Controlled Trial." Annals of Internal Medicine [http://www.annals.org/cgi/reprint/133/4/245.pdf]</ref>
== Biological role ==
Zinc is an essential element, necessary for sustaining all life. It is estimated that 3000 of the hundreds of thousands of proteins in the human body contain zinc [[prosthetic groups]], one type of which is the so-called [[zinc finger]].{{Fact|date=February 2007}} In addition, there are over a dozen types of cells in the human body that secrete zinc ions, and the roles of these secreted zinc signals in medicine and health are now being actively studied. Intriguingly, brain cells in the mammalian forebrain are one type of cell that secretes zinc, along with its other neuronal messenger substances. Cells in the salivary gland, prostate, immune system and intestine are other types that secrete zinc.{{Fact|date=February 2007}}
Zinc is an activator of certain enzymes, such as carbonic anhydrase. Carbonic anhydrase is important in the transport of carbon dioxide in vertebrate blood. It is also required in plants for leaf formation, the synthesis of indole acetic acid (auxin) and anaerobic respiration (alcoholic fermentation).{{Fact|date=February 2007}}
=== Food sources ===
Zinc is found in oysters, and to a far lesser degree in most animal proteins, beans, nuts, almonds, whole grains, pumpkin seeds and sunflower seeds. [[Phytates]], which are found in whole grain breads, cereals, legumes and other products, have been known to decrease zinc absorption. Clinical studies have found that zinc, combined with [[antioxidants]], may delay progression of age-related [[macular degeneration]],{{Fact|date=February 2007}} but the effect is extremely small and not likely to be clinically important. Significant dietary intake of zinc has also recently been shown to impede the onset of flu.{{Fact|date=February 2007}} [[Soil conservation]] analyzes the vegetative uptake of naturally occurring zinc in many soil types.
The (US) [[Reference Daily Intake|recommended dietary allowance]] of zinc from puberty on is 11mg for males and 8mg for females, with higher amounts recommended during pregnancy and lactation.
=== Zinc deficiency ===
Zinc deficiency results from inadequate intake of zinc, or inadequate absorption of zinc into the body. Signs of zinc deficiency includes hair loss, [[skin]] lesions, [[diarrhea]], wasting of body tissues, and, eventually, death. Eyesight, taste, smell and memory are also connected with zinc. A deficiency in zinc can cause malfunctions of these organs and functions. Congenital abnormalities causing zinc deficiency may lead to a disease called [[Acrodermatitis enteropathica]].
Obtaining a sufficient zinc intake during [[pregnancy]] and in young children is a very real problem, especially among those who cannot afford a good and varied diet. [[Brain]] development is stunted by zinc insufficiency in utero and in youth.
==== Zinc deficiency as a cause of anorexia nervosa ====
{{main|Anorexia nervosa}}
Zinc deficiency causes a decrease in [[appetite]] -- which could degenerate in anorexia nervosa (AN). Appetite disorders, in turn, cause [[malnutrition]] and, notably, inadequate zinc nutriture. The use of zinc in the treatment of anorexia nervosa has been advocated since 1979 by Bakan. At least 5 trials showed that zinc improved weight gain in anorexia. A 1994 randomized, double-blind, placebo-controlled trial showed that zinc (14 mg per day) doubled the rate of body mass increase in the treatment of anorexia nervosa (AN).
Deficiency of other [[nutrients]] such as [[tyrosine]] and [[tryptophan]] (precursors of the [[monoamine]] [[neurotransmitter]]s [[norepinephrine]] and [[serotonin]], respectively), as well as vitamin B1 ([[thiamine]]) could contribute to this phenomenon of malnutrition-induced malnutrition.<ref name="Zincappetitereview">Neurobiology of Zinc-Influenced Eating Behavior | [http://jn.nutrition.org/cgi/content/full/130/5/1493S]</ref>
* Inadequate zinc nutriture, however, is not only involved in such an extreme appetite dysregulation as AN. Growth, appetite and zinc status have been shown to be correlated.<ref name="Zincappetitereview"/>
=== Zinc toxicity ===
Even though zinc is an essential requirement for a healthy body, too much zinc can be harmful. Excessive absorption of zinc can also suppress copper and iron absorption. The free zinc ion in solution is highly toxic to plants, invertebrates, and even vertebrate fish. The Free Ion Activity Model (FIAM) is well-established in the literature, and shows that just [[mole (unit)|micromolar]] amounts of the free ion kills some organisms. A recent example showed 6 micromolar killing 93% of all daphnia in water.<ref>Muyssen et al., (Aquat Toxicol. 2006)</ref> Swallowing an American one cent piece (98% zinc) can also cause damage to the stomach lining due to the high solubility of the zinc ion in the acidic stomach.<ref>Bothwell and Mair, PEDIATRICS 2003</ref> Zinc toxicity, mostly in the form of the ingestion of US pennies minted after 1982, is commonly fatal in dogs where it causes a severe [[hemolytic anemia]].<ref>Stowe CM, Nelson R, Werdin R, et al: Zinc phosphide poisoning in dogs. JAVMA 173:270, 1978</ref>
=== Immune system ===
Zinc salts are effective against [[pathogen]]s in direct application. [[Gastrointestinal infections]] are also strongly attenuated by ingestion of zinc, and this effect could be due to direct antimicrobial action of the zinc ions in the GI tract, or to absorption of the zinc and re-release from immune cells (all granulocytes secrete zinc) or both.
The direct effect of zinc (as in lozenges) on bacteria and viruses is also well-established, and has been used since at least 2000 BC, from when zinc salts in palliative salves are documented. However, exactly how to deliver zinc salts against pathogens without injuring one's own tissues is still being investigated.
== Abundance ==
:''See also: [[:Category:Zinc minerals|Zinc minerals]]
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