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Chapter 11 Macrominerals 2009 Cengage-Wadsworth.

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

1 Chapter 11 Macrominerals 2009 Cengage-Wadsworth

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

3 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 2009 Cengage-Wadsworth

4 Calcium Transport Regulation of calcium concentrations
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 2009 Cengage-Wadsworth

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

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

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

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

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

10 Phosphorus Absorption - 2 processes Transport & storage
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 2009 Cengage-Wadsworth

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

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

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

14 Magnesium Sources Absorption & transport 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 2009 Cengage-Wadsworth

15 Magnesium Functions & mechanisms of action 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 2009 Cengage-Wadsworth

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

17 Magnesium Recommended Dietary Allowance 19-30 years 31 & >
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 2009 Cengage-Wadsworth

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

19 Sodium Sources Absorption, transport, & function Added salt
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 2009 Cengage-Wadsworth

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

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

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

23 Potassium Sources Absorption, transport, & function
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 2009 Cengage-Wadsworth

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

25 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 2009 Cengage-Wadsworth

26 Chloride Sources Absorption, transport, & secretion
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 2009 Cengage-Wadsworth

27 Chloride Functions Excretion Major electrolyte
Gastric hydrochloric acid Phagocytosis Exchange anion for HCO3- in RBC Excretion 3 routes: GI tract, skin, kidneys 2009 Cengage-Wadsworth

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

29 Macrominerals & Hypertension
Perspective 11 Macrominerals & Hypertension 2009 Cengage-Wadsworth

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

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