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 2009 Cengage-Wadsworth Chapter 11 Macrominerals.

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Presentation on theme: " 2009 Cengage-Wadsworth Chapter 11 Macrominerals."— Presentation transcript:

1  2009 Cengage-Wadsworth Chapter 11 Macrominerals

2  2009 Cengage-Wadsworth Calcium Sources –Dairy, some seafoods Digestion, absorption, & transport –Digestion Present in relatively insoluble salts If solubilized, can bind to other compounds

3  2009 Cengage-Wadsworth Calcium Absorption - 2 processes –Duodenum & proximal jejunum; saturable, requires energy, involves calcium-binding transport protein (CBP), stimulated by calcitriol & low-calcium diets –Small intestine, mostly jejunum & ileum; paracellular; passive diffusion, requires no carrier –Factors influencing absorption »Vitamin D, lactose, phytate, oxalate, divalent cations, fatty acids, type of supplement

4  2009 Cengage-Wadsworth Calcium Transport –Bound to proteins (e.g. albumin, prealbumin), complexed with sulfate, free Regulation of calcium concentrations –Extracellular calcium concentration regulation »PTH »Calcitriol »Calcitonin –Intracellular calcium concentration regulation

5  2009 Cengage-Wadsworth Calcium Functions & mechanisms of action –Cortical bone vs. trabecular bone –Bone mineralization –Other roles Blood clotting Nerve conduction Muscle contraction Enzyme regulation Membrane permeability

6  2009 Cengage-Wadsworth Calcium Interactions with other nutrients –Phosphorus –Protein –Sodium –Caffeine –Iron –Lead –Fatty acids

7  2009 Cengage-Wadsworth Calcium Excretion –Urine, feces, skin Adequate Intake –19-50 years: 1,000 mg –51 & >: 1,200 mg Deficiency –Osteoporosis –Hypertension, colon cancer, obesity

8  2009 Cengage-Wadsworth Calcium Toxicity –UL = 2,500 mg Assessment of nutriture –Serum calcium - tightly regulated by hormones –Bone densitometry –Neuron activation –Dual-energy X-ray absorptiometry

9  2009 Cengage-Wadsworth Phosphorus Sources –Meat, poultry, fish, eggs, dairy Digestion, absorption, transport, & storage –Digestion Hydrolyzed to inorganic phosphate

10  2009 Cengage-Wadsworth Phosphorus Absorption - 2 processes –Saturable, carrier-mediated transport system dependent on sodium & enhanced by calcitriol –Concentration-dependent facilitated diffusion –Factors influencing absorption »Vitamin D, phytate, other minerals Transport & storage –Transported in inorganic & organic forms –In all cells, most in bone & muscle

11  2009 Cengage-Wadsworth Phosphorus Functions & mechanisms of action –Bone mineralization –Nucleotide/nucleoside phophates Structural roles Energy storage & transfer Intracellular second messenger –Phosphoproteins –Structural roles

12  2009 Cengage-Wadsworth Phosphorus –Acid-base balance –Oxygen availability Excretion –Urine (67%-90%) & feces (10%- 33%) Recommended Dietary Allowance –19 years & >: 700 mg

13  2009 Cengage-Wadsworth Phosphorus Deficiency –Rare; renal patients, refeeding Toxicity –UL = 9-70: 4 g; >70: 3 g Assessment of nutriture –Serum concentrations –Urinary excretions

14  2009 Cengage-Wadsworth Magnesium Sources –Coffee, tea, cocoa –Nuts, legumes, whole grains Absorption & transport –Absorption - 2 systems Saturable, carrier-mediated active transporter - low intakes Simple diffusion - higher intakes Factors influencing absorption

15  2009 Cengage-Wadsworth Magnesium –Transport 50%-55% free, 33% bound to protein, 13% complexed with ions Functions & mechanisms of action –Bone lattice & surface –>300 enzyme reactions as structural cofactor or allosteric activator

16  2009 Cengage-Wadsworth Magnesium Interactions with other nutrients –Calcium –Phosphorus –Potassium –Protein Excretion –Urine, feces (mostly unabsorbed)

17  2009 Cengage-Wadsworth Magnesium Recommended Dietary Allowance –19-30 years Men: 400 mg; women: 310 mg Pregnancy: 350 mg; lactation; 310 mg –31 & > Men: 420 mg; women: 320 mg Pregnancy: 360 mg; lactation: 320 mg

18  2009 Cengage-Wadsworth Magnesium Deficiency –Usually associated with illness Toxicity –UL = 350 mg (non-food sources) Assessment of nutriture –Serum concentrations –Renal excretion before & after administration of Mg load

19  2009 Cengage-Wadsworth Sodium Sources –Added salt Absorption, transport, & function –3 pathways for absorption Na + /glucose cotransport system - whole small intestine Electroneutral Na + & Cl - cotransport system - small intestine & proximal colon Electrogenic Na absorption mechanism - colon

20  2009 Cengage-Wadsworth Sodium –Transport Free in blood –Functions Maintenance of fluid balance Nerve transmission/impulse conduction Muscle contraction

21  2009 Cengage-Wadsworth Sodium Interactions with other nutrients –Calcium Excretion –Primarily urine, sweat Deficiency –Excessive sweating

22  2009 Cengage-Wadsworth Sodium Adequate Intake & assessment of nutriture –AI = 1500 mg –UL = 2300 mg –Ion-selective electrode potentiometry Used on blood & other body fluids

23  2009 Cengage-Wadsworth Potassium Sources –Unprocessed foods; some fruits & vegetables, legumes, nuts, seeds Absorption, transport, & function –Absorbed by passive diffusion or K + / H + - ATPase pump –Contractility of smooth, skeletal & cardiac muscle –Excitability of nerve tissue –Maintenance of electrolyte & pH balance

24  2009 Cengage-Wadsworth Potassium Interactions with other nutrients –Calcium Excretion –Urine (~90%), feces Deficiency & toxicity –Hyperkalemia - high serum potassium –Hypokalemia - low serum potassium

25  2009 Cengage-Wadsworth Potassium Adequate Intake & assessment of nutriture –AI = 4,700 mg –No UL for K from foods –Plasma K concentrations determined by ion-selective electrode potentiometry

26  2009 Cengage-Wadsworth Chloride Sources –Salt, eggs, fresh meat, seafood Absorption, transport, & secretion –Absorption similar to that of Na –Major secretory product of stomach Electrogenic Cl - secretion –Disfunctional Cl transport - cystic fibrosis

27  2009 Cengage-Wadsworth Chloride Functions –Major electrolyte –Gastric hydrochloric acid –Phagocytosis –Exchange anion for HCO 3 - in RBC Excretion –3 routes: GI tract, skin, kidneys

28  2009 Cengage-Wadsworth Chloride Deficiency –Severe diarrhea & vomiting Adequate Intake & assessment of nutriture –AI = 2300 mg –UL = 3.6 g –Serum concentration Ion-selective electrode potentiometry Coulometric titration

29  2009 Cengage-Wadsworth Perspective 11 Macrominerals & Hypertension

30  2009 Cengage-Wadsworth Hypertension Sodium Potassium Calcium Magnesium Other dietary factors


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