20. Mineral Met Blok V

8/12/2019 20. Mineral Met Blok V

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MINERALMETABOLISM


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Macro Elements

Ca, Mg, Na, K, P, Li,S, Cl

60 80% of inorganic compound in the body

Micro Elements

Very small amounts in the body

Essentials: Fe, Zn, Cu, Mn, I, Mo, Co, Se, Cr Suspected essentials are Ni, F, Br, As, Va, Cd,

Ba, Sr

Non-essentials are Al, Hg, Ag, Pb, Ge


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Calcium

+ 99% of body calcium is as hydroxyapatite in the

skeleton

Adult requirement: 0.5-1.0 mgCa/day

Absorption of it is decreased by

Lack of vit.D

excess of phytates low Ca/P ratio in diet


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Phosphorus + 15% of it is in muscle and other soft tissues & +

85% is in bone

is an integral part of macromolecules (e.g.phospholipids, phosphoproteins and nucleic acids)

is absorbed easily and rapidly (70%)

Its excretion is equivalent to dietary phosphate intake

maintenance of skeletal mineral structure and buffersystem

Is required for transport of fatty acids, vitamin,enzyme system and muscle energy metabolism


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Zinc

Is an integral part of numerous enzymesassociated with Carbohydrate & energy metabolism Protein synthesis & degradation Nucleic acid synthesis Intracellular transport functions Protection of cells from oxidative damage

Plays a role in maintaining exocrine & endocrine

pancreatic function

Spermatogenesis is a zinc-dependent process based onthe metals role in testosterone metabolism


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Zinc

Absorption of Zn is an active process & shares guttransport mechanisms wit copper & iron (is bound tometallothioneine)

Its excess interfere with copper absorption

Zn loss in renal disease is due to its association withplasma albumin

Zn deficiency is characterized by Growth retardation Skin lesions Impairment of sexual development, taste & smell Delay of wound healing


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COPPER

Associated with several oxygenase enzymes(cytochrome oxidase, SOD, ceruloplasmin & lysyloxidase) SOD is scavenging of superoxide & other reactive

axygen spacies Lysyl oxidase is related with cross-linking of collagen

Its absorption is bound to metallothioneine

Excess cause liver cirrhosis

Acute toxicity is manifested by marked Hemolysis Damage to both liver and brain cells


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COPPER

Deficiency results inAnemia microcytic hypochromic (pale erythrocyte)

resistent to iron therapy (related to ceruloplasmin) Reduction in number of leukocytes Degenerative of vascular tissue with bleeding (due

to defects in elastin & collagen prodcution)


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MINERAL & METABOLIC

DISORDERS


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Zinc

stabilizes cell membranes

Zinc (metalloenzymes): a component of cysteine

residues, in organelle membranes and polyribosomes

is a enzyme cofactor

cofactor for RNA and DNA polymerase

involved in synthesis of DNA, RNA & ribosomes

required for gene expression, cell differentiation

and cell replication.

needed for cell mitosis and cell proliferation in wound

repair


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cell growth/proliferation sexual maturation/reproduction dark adaptation/night vision gustatory acuity wound healing

host immune defenses

protects against ultraviolet (UV) radiation(Topical zinc, in the form of divalent zinc ionsprovide antioxidantphotoprotection for skin).

enhances wound healing contributes to immune and neuropsychiatric functions decreases the relative risk of cancer & cardiovascular

disease (metalloenzymes: superoxide dismutase).

Functions of zinc inhumans:


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Zinc


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+ 2 to 3 g zinc stores: + 1/5 is in bone + 1/2 is in the liver. the remain in the skeletal muscle.

Serum binding: + 55% albumin + 40% to an -acroglobulin (a zinc metalloprotein).

Zinc is lost:

in fistula output 12 mg/l in diarrhea 17 mg/l. In sweat up to 1 mg zinc per liter skin losses become important with dermatologic

patients or those with burns

Zinc


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Zinc losses increase in: Diseases: sickle cell anemia, malignancies, diabetes, inflammatory

or infectious conditions Medications: estrogens, caffeine, theophylline, & corticosteroids.

Short-term zinc depletion greatly influences serum testosterone concentrations seminal volume total seminal zinc loss per ejaculate.

Daily absorption: + oral zinc is absorbed in the duodenum and proximal jejunum. copper and iron may suppress zinc absorption. vitamin D may increase zinc bioavailability

In zinc deficiency: decreases fibroblast proliferation and collagen synthesis impairs cellular and humoral immunity impairs growth, protein and DNA synthesis and cell division.


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Sites of absorption of nutrientswithin gastrointestinal tract:


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Zinc deficiency On of ten biggest factors contributing to burden ofdisease in developing countries

Zinc interventions could reduce child deaths globallyby 63%

South East Asia and Sub-Saharan Africahighest risk

of zinc deficiency: Inadequate intake1/3 of the population Stunting40% of pre-schoolers

Inadequate Zinc deficiency

Few global policies or recommendations for interventions Zinc used as a (part of) curative intervention for severe

malnutrition and diarrhea


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alopecia - diarrhea glucose intolerance - hypospermia impaired chemotaxis - night blindness depression - apathy delayed wound healing - skin lesions dermatological anergy - growth retardation impaired taste immunological impairment hypogonadism hypospermia mental depression

Zinc deficiency signs andsymptoms:


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Iron is required for hydroxylation of proline and lysine severe iron deficiency can result in

impaired collagen production.

As a part of oxygen transport system.

iron deficiency can result from blood loss infectious causes malnutrition hematopoietic disorder.

Cellular respiration, ATP storage using iron-couplingreactions


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Iron Possibly T-cell immunity and cognitive function

actions may require iron. Iron deficiency results in a slight decrease in forming T

cells and a significant impairment of lymphocyteresponse to mutagens and antigens.

Toxicity (hemosiderosis) mainly as a result of saturation of hemosiderin stores can result from multiple blood transfusions, because

blood contains about 0.5 mg iron/ml.


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Iron deficiency

Categorized as one of top ten most serioushealth problems in the modern world (WHO)

As many as 4-5 billion people (66-80% ofpopulation) may be iron deficient

2 billion people (>30% of population) are anemic Iron deficiency is associated with developmental

delays of cognitive and motor skills

Iron deficient children tend to be pale, weak, eat less, tire easily, be more irritable, have

shorter attention spans, fall ill more frequently, and failto grow normally


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Copper

is integral part of enzyme lysyloxidase

catalyzes formation of stable collagen cross-links

Some cuproenzymes paly important role in oxidation

reduction reaction:


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Role of copper-binding proteins in

humans


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Dietary copper bioavailability (40 to 60%) can beaffected by other nutrients

status of ceruloplasmin.

Copper stores (+ 120 mg) are mainly in liver

are secreted in saliva, gastric & pancreatic juice & bile

Coppermetallothionein complex present in intestinalmucosal cells is shed into intestinal lumen.


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Iodine

is important in cellular oxidative processes

associated with thyroid functions.

Iodine deficiency:

causes endemic cretinism, associated with deaf

mutism & cerebral palsy. Principal role of iodine in man is:

its incorporation into thyroid hormones (T3 and T4):

regulate cellular metabolism, temperature, and normal growth.

+ 2/3 of total body iodine is found in thyroid.


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Iodine deficiency

Iodine deficiency is the worlds most prevalentcause of brain damage

Serious iodine deficiency during pregnancymay result in stillbirths, abortions and

cretinism

Yet, the less visible, more pervasive form ofiron deficiency that lowers intellectual

performance at home and school may havefar greater global and economic impact


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Manganese

Mn-SOD and pyruvate carboxylase are two most

important metalloenzymes of manganese.

Play important role in homeostasis of metabolicsynthesis of: proteins, (mucopolysaccharides & prothrombin) carbohydrate and lipid (e.g., activates lipoprotein lipase

activation, cholesterol, and sex hormone precursors

Stores are found in mitochondria of hepatic,renal, pancreatitic, bone, and skeletal muscleparenchyma.


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Manganese

Deficiencies have been manifested as: tardive dyskinesia epilepsy diabetes mellitus pancreatic insufficiency malnutrition hair color changes hypercholesterolemia prolonged prothrombin times.


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Magnesium (Mg)

is a macromineral that is essential for woundrepair

is a cofactor for many enzymes that are involved

in process of protein synthesis.

The primary role of magnesium is to provide

structural stability to ATP, which powers many ofthe processes used in collagen synthesis,

making it a factor essential to wound repair


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Magnesium modulates cellular events involved ininflammation.

Mg deficiency in rat induces a clinicalinflammatory syndrome characterized by polymorphonuclear (PMN) leukocyte macrophage activation

release of inflammatory cytokines and acute phaseproteins excessive production of free radicals.

Mg acts as a natural calcium antagonist

molecular basis for inflammatory response is probablyresult of modulation of intracellular calcium concentration


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Mg deficiency contributes to an exaggerated: response to immune stress hyperlipemia atherosclerosis endothelial dysfunction thrombosis hypertension free radical damage


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Assessment of magnesium status:

urine magnesium concentration is the most precise

When sufficient excretion is evident (i.e., greater than50% of intake)

intracellular magnesium concentration is sufficient.

Magnesium and zinc:

both essential for enzymatic activity

maintaining three-dimensional structures of proteins synthesis of nucleic acids and proteins


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Calcium:

High levels of intracellular Ca2 are associated

with irreversible progression from cell injury tocell death.

A dietary deficiency of calcium can lead to

osteoporosis, a disease in which bones areinsufficiently mineralized and consequently arefragile and easily fractured.

Osteoporosis is a particularly common problemamong elderly women.


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Phosphorus

Phosphorus is required for the formation ofATP and of phosphorylated intermediates inmetabolism.

Deficiency of phosphorus results in bone lossalong with weakness, anorexia, malaise, andpain.

Deficiency of phosphorus results in bone lossalong with weakness, anorexia, malaise, andpain.

20. Mineral Met Blok V

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