Copper and Zinc Review

ZINC

Insulin
SOD
Cognitive function
Male sex health
Oysters - aphrodisiac - very high zn content
Beef pork
Seeds




DIGESTION, ABSORPTION, TRANSPORT

Similar to NON-heme iron

Digestion:

• HCl
• Proteases & Nucleases release from food

Absorption:

• Carrier (ZIP4) mediated process of low-moderate intake
• Passive paracellular diffusion with high intake
• Affected by enhancers and inhibitrs
• Enhancers:
• Organic acids
• Glutathione
• Amino acids
• low pH
• Inhibitors:
• Phytic acid
• Oxalic acid
• Selectred nutritients
• Iron
• Calcium
• High pH

Availability from meat better than vegetables

ZINC in the ENTEROCYTE
Used for gut cell functions
Temporary storage may be excreted

• Metallothionein is primary  storage protein

Transported into circulation by ZnT1
Albumin is primary blood carrier protein

ZINC STORAGE and EXCRETION
Storage:

• Found in all tissues esp liver, kidney, muscles, skin, bones
• Mostly in functional and structural proteins
• Liver can respond to low zinc status by releasing zinc
• Metallothionein is primary storage protein
• Also bind other mineral and has antioxidant activity

Excretion

• Mainly in GIT
• Unabsorbed zinc
• Sloughed intestinal cells
• Secreted zinc proteins
• Carrier based transport
• Small amounts via kidney and skin

FUNCTIONS and MOA
Numerous enzyme roles

• Structural integrity of enzyme
• Catalytic activity of enzyme

Gene Expression

• Zn finger structures in transcription factors
• Zn binds to portions of transcription factors proteins
• Resulting shape allows binding to regulatory region of gene
• May also participate in regulation of RNA translation

Structure and function of cellular membranes

Other roles

• Acid base balance
• CARBONIC ANHYDRASE
• Vitamin A and alcohol metabolism
• Retinol to retinal
• Protein digestion
• Antioxidant defence
• SOD (also copper)
• Folate digestion
• Wound repair
• Immune function
• Cell mediated and humoral immunity
• Cytokine production and thymulin activity
• Cell replication and growth
• Nucleic acid metabolism
• Protein synthesis
• Gene expression regulation
• Taste function ~ gustin
• Carbohydrate metabolism
• Pancreatic insulin storage
• Insulin response pathway

INTERACTIONS
Copper
Iron

DEFICIENCY


COPPER

Cu3+
Cu2+

DIGESTION and ABSORPTION

Gastric HCl and enzymes required

Reduction to Cu1+ required
Transporters Ctr1 and DMT 1
Affected by enhancer and inhibitors

• Enhancers
• Some amino acids
• low pH
• Glutathione
• Acids
• Inhibitors
• high pH
• Phytic acids

In the enterocytes

• Chaperones bind copper and deliver it to targets
• Enzymes for functional uses
• Metallothionein for temporary storage
• High zn intake causes increased copper loses
• ATPase 7A for entry into blood
• Ceruloplasmin formed in liver is primary carrier
• Menke's disease

Storage

• Liver is primary storage organ
• Metallothionine is primary storage organ

Excretion

• Mainly via secretion into bile
• Small amounts via kidney and skin

FUNCTIONs and MOA

• Ceruloplasmin
• Fe2+ oxidation for transport
• Antioxidant
• SOD
• Energy production
• Cytochrome oxidase ATP production
• Amine oxidases
• Catabolism of histamine neurotransmitters
• Connective tissue stabilization
• Collagen and elstin cross-linking
• Tyrosine metabolism
• NEPI synthesis
• Melanin production
• Pro-oxidant when unbound
• Wilson Disease
• Immune function
• Gene expression