Function – Zinc contributes to:
The normal function of the immune system - Zinc deficiency is associated with a decline in most aspects of immune function. Zinc deficiency renders people more susceptible to infections, while zinc supplementation in humans has shown benefit in immune responses to bacterial and viral infections (IoM, 2001).
The maintenance of normal hair - Clinical manifestations of marginal to severe human zinc deficiency include various epithelial lesions. After the onset of dermatitis, the hair may become hypopigmented and acquire a reddish hue. Patchy loss of hair is a feature of zinc deficiency.
The maintenance of normal nails - Clinical manifestations of marginal to severe human zinc deficiency include various epithelial lesions. Nail dystrophy has been reported as a symptom of zinc deficiency (King and Cousins, 2006).
The maintenance of normal skin - One of the clinical manifestations of severe zinc deficiency in humans is akrodermatitis, characterised by erythematous, vesiculobullous, and pustular rashes primarily around the body orifices and at the extremities.
Normal fertility and reproduction - Zinc plays a role in reproduction in males and females. Spermatogenesis is a zinc dependent process and seminal fluid is particularly rich in zinc.
The maintenance of normal testosterone levels in the blood - An important class of “zinc finger” transcription factors is the steroid/thyroid receptor superfamily, which is responsible for mediating the biological response to a wide range of hormonal and metabolic signals (Freake, 2006).
The maintenance of normal vision - Zinc regulates the metabolic conversion of retinol to retinaldeyde (retinal) through the zinc-dependent enzyme retinol dehydrogenase. The conversion of retinol to retinal is a critical step in the visual cycle in the retina of the eye (Christian and West, 1998).
Normal metabolism of vitamin A - Zinc participates in the absorption, mobilization, transport and metabolism of micronutrients, including vitamin A, through its involvement in protein synthesis and cellular enzyme functions (IoM, 2001).
The protection of cells from oxidative stress - Zinc participates in the antioxidant defense system of the body. It can bind to thiol groups in proteins, making them less susceptible to oxidation. By displacing redox-reactive metals such as iron and copper from both proteins and lipids it can reduce the metal-induced formation of hydroxyl radicals and thus protect the macromolecules.
Normal acid-base metabolism - Zinc has essential structural, regulatory or catalytic roles in many enzymes. Carbonic anhydrase, is a zinc metalloenzyme, where zinc is a direct participant in the catalytic function.
Normal carbohydrate metabolism/ protein synthesis - Zinc is an essential component of a large number of enzymes that participate in the synthesis and degradation of carbohydrates, lipids, proteins and nucleic acids (Freake, 2006)
Normal cognitive function - In the central nervous system zinc has a role as a neurosecretory product or cofactor, and is highly concentrated in the synaptic vesicles of specific neurons.
Normal macronutrient metabolism - Its main physiological impact is in all steps of protein synthesis. Zinc activates DNA and RNA polymerases and is essential to histones regulation. It is also involved in several peptidic hormones stabilization (insulin, gustin, thymulin)”.
Normal metabolism of fatty acids - Zinc is necessary for the conversion of linoleic acid to gamma-linolenic acid and the mobilization of dihomogammalinolenic acid for the synthesis of series-1 prostaglandins (IoM, 2001).
The maintenance of normal bones - Zinc is an essential cofactor for enzymes involved in synthesis of various bone matrix constituents and plays a particularly important role in the regulation of bone deposition and resorption. Zinc also plays a structural role in the bone matrix.
Zinc has a role in the process of cell division and contributes to a normal DNA synthesis - Zinc has essential structural, regulatory or catalytic roles in many enzymes. Zinc plays a role in the stabilization of genetic material and is an essential component of some enzymes that participate in the synthesis of nucleic acids.
Studies suggest that taking high levels of vit C and Zinc, even as symptoms appear have been shown to reduce severity of rhinorrea