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Zinc
Found in:
Meat/fish/poultry (liver, lamb, turkey); cereal and grain products (wheat germ and bran, oats, whole wheat bread, rye, and white rice);
dairy and egg products; vegetables (green peas, spinach, corn, boiled potato, iceberg lettuce, carrot, and cabbage); fruits
(cherries, oranges, and pears).
What is known to be good for:
Boosts immune system and may reduce duration of cold symptoms, fight graying and thinning hair.
It stimulates the activity of about 100 enzymes, substances that promote biochemical reactions in your body. Among its many functions,
zinc maintains a healthy immune system, is needed for wound healing, helps maintain the sense of taste and smell, and is needed for
DNA synthesis.
Other functions of Zinc:
Zinc plays diverse roles in carbohydrate, lipid, protein and nucleic acid metabolism and in cell growth.
Zinc is a cofactor for aldolase (glycolysis), malate dehydrogenase (in citric acid cycle), cytochrome C
(in the electron transport system - Brain Functions) and glutamate dehydrogenase (in amino acid synthesis and catabolism).
Other enzymes for which zinc is a cofactor include carboxypeptidases (digestive enzymes), alkaline phosphatase, retinene reductase
(which converts retinol to retinal) and superoxidase dismutase (a cellular antioxidant).
Zinc is a constituent of carbonic anhydrase which serves to rid the body of carbon dioxide by converting it to
carbonic acid. Zinc is required for protein, carbohydrate, mucopolysaccharide, lipid and nucleic acid metabolism. It is necessary for
cell division, growth and repair; for example zinc is required for the activity of both DNA and RNA polymerase.
Zinc also serves as a ligand, binding to and stabilizing various compounds.
Lack of Zinc:
The deficiency is characterized by growth retardation, hypogonadism and delayed sexual maturation. Also poor appetite and changes in
the perception of taste and smell; Lethargy; slowing of activity; apathy and depression. Impaired cell-mediated immunity, slow wound healing;
dermatitis and failure to thrive are other manifestations of this nutritional problem. There is also evidence to indicate that
zinc deficiency in infants may lead to deficits in children's neuropsychological functions, activity or motor development subsequently
interfering with their cognitive development and performance.
Excess of Zinc can:
Zinc has relatively low toxicity with a wide margin of safety between requirement and toxic intake. However, therapeutic use of zinc
salts at levels of 50 mg of elemental zinc per day can result in transient nausea.
Do you know where you find Zinc in your body?
Zinc is an essential mineral that is found in every cell in our body.
Storage and manipulation of suppliers of Zinc:
In general, the concentration of zinc in animal foods is
higher and is more available than in vegetable products.
The availability of zinc in plant products is decreased by the
presence of fiber and phytates which bind to zinc rendering it
unavailable.
Absorption, Storage and Excretion
Zinc absorption in the gut is facilitated by the presence of a low molecular weight ligand believed to be secreted by the pancreas.
The ligand is present in human breastmilk thereby enhancing the bioavailability of zinc. Once absorbed by the enterocyte, zinc may be used
for cellular processes, complexed to metallothionein or released into the circulation bound to a serum protein.
The release of zinc into the portal circulation is believed to be under homeostatic control. Circulating zinc may be bound to albumin
(57% of the total plasma zinc), macroglobulin (40%), various amino acids and possibly other molecules (3%).
The main route of zinc excretion is via the gastrointestinal tract. Zinc is also excreted in the urine and sweat (maybe be significant in
hot climates).
Source:Source: HEINZ HANDBOOK of Nutrition, 9th. EDITION, Edited by David L.
Yeung, Ph.D. and Idamarie Laquatra, Ph.D., R.D.
Adapted by Editorial Staff, October 2007
Last update, August 2008
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