ZINC
INTRODUCTION AND NUTRITIONAL IMPORTANCE
Zinc is an essential trace element that is required for the normal functioning of
numerous biochemical, physiological, and molecular processes in the human body.
It is the second most abundant trace mineral after iron and is present in all body
tissues and fluids. Unlike some minerals, zinc is not stored in large amounts in the
body, making continuous dietary intake necessary. Zinc plays a fundamental role in
enzyme catalysis, gene expression, immune function, growth and development,
and cellular signaling, emphasizing its critical importance in nutritional chemistry.
CHEMICAL CHARACTERISTICS AND FORMS OF ZINC
Zinc is a divalent cation (Zn²⁺) under physiological conditions and is chemically
stable, redox-inert, and does not participate in oxidation–reduction reactions. This
property allows zinc to function as a structural and catalytic ion without generating
free radicals.
In the diet, zinc exists primarily in ionic form bound to proteins or organic ligands.
Unlike selenium, zinc does not have distinct organic and inorganic nutritional
forms; however, its bioavailability is influenced by the chemical environment of
foods, such as the presence of phytates, fiber, and competing minerals.
, ABSORPTION, TRANSPORT, AND HOMEOSTASIS
Zinc absorption occurs mainly in the jejunum of the small intestine through carrier-
mediated transport systems, particularly ZIP (Zrt- and Irt-like Protein) transporters.
Absorption efficiency ranges from 15% to 40% and is influenced by dietary
composition and physiological status.
Once absorbed, zinc binds to albumin and α-2-macroglobulin in the plasma and is
transported to tissues. Major sites of zinc distribution include skeletal muscle, bone,
liver, pancreas, and skin. Cellular zinc levels are tightly regulated by
metallothioneins, which bind zinc and protect cells from zinc toxicity while
maintaining intracellular zinc availability.
Zinc homeostasis is maintained primarily through intestinal excretion, with minor
losses through urine, sweat, hair, and sloughed skin cells.
INTRODUCTION AND NUTRITIONAL IMPORTANCE
Zinc is an essential trace element that is required for the normal functioning of
numerous biochemical, physiological, and molecular processes in the human body.
It is the second most abundant trace mineral after iron and is present in all body
tissues and fluids. Unlike some minerals, zinc is not stored in large amounts in the
body, making continuous dietary intake necessary. Zinc plays a fundamental role in
enzyme catalysis, gene expression, immune function, growth and development,
and cellular signaling, emphasizing its critical importance in nutritional chemistry.
CHEMICAL CHARACTERISTICS AND FORMS OF ZINC
Zinc is a divalent cation (Zn²⁺) under physiological conditions and is chemically
stable, redox-inert, and does not participate in oxidation–reduction reactions. This
property allows zinc to function as a structural and catalytic ion without generating
free radicals.
In the diet, zinc exists primarily in ionic form bound to proteins or organic ligands.
Unlike selenium, zinc does not have distinct organic and inorganic nutritional
forms; however, its bioavailability is influenced by the chemical environment of
foods, such as the presence of phytates, fiber, and competing minerals.
, ABSORPTION, TRANSPORT, AND HOMEOSTASIS
Zinc absorption occurs mainly in the jejunum of the small intestine through carrier-
mediated transport systems, particularly ZIP (Zrt- and Irt-like Protein) transporters.
Absorption efficiency ranges from 15% to 40% and is influenced by dietary
composition and physiological status.
Once absorbed, zinc binds to albumin and α-2-macroglobulin in the plasma and is
transported to tissues. Major sites of zinc distribution include skeletal muscle, bone,
liver, pancreas, and skin. Cellular zinc levels are tightly regulated by
metallothioneins, which bind zinc and protect cells from zinc toxicity while
maintaining intracellular zinc availability.
Zinc homeostasis is maintained primarily through intestinal excretion, with minor
losses through urine, sweat, hair, and sloughed skin cells.
