Minerals
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Transcript of Minerals
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Minerals
Chapters 12 and 13
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Inorganic ions, essential2 classes
1) Macrominerals >5gm in bodySulfur Phosphorous CalciumSodium Potassium ChlorideMagnesium
2) Trace minerals <5gm in bodyIron Copper SeleniumManganese Iodine Zinc
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Macrominerals
Potassium Sodium ChlorideRequirement dependent body waterMaintain fluid balanceNo RDA
Calcium Magnesium PhosphorousEstablished RDABone growth metabolism
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Sodium
1) Function1o role: Maintenance ECF volumeAcid/base balanceNerve transmissionMuscle contraction
2) Absorption/MetabolismReadily absorbedFiltered in kidneysControlled release into blood
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3) Dietary SourcesSalt (NaCl) 40% SodiumPresent most foodsProcessed foods, sauces
4) Dietary RecommendationsDECREASE!Minimum requirement 500mg/day US
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Health Consequences of Sodium
1) High Blood PressureGenetic sensitivitySalt restriction helps BPControversial role normal BP
2) OsteoporosisSodium Calcium excretionDietary advice: Calcium Sodium
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DeficiencyExcessive vomiting, sweating, diarrhea Results in: seizures, muscle cramps, mental apathy, loss appetiteReplace with fluid replacement
Toxicity:Fluid balance upsetEdema & hypertensionIncrease water intake required
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Potassium
1) Function1o function maintain intracellular volumeNa+/K+ exchange facilitates:A) Muscle contractionB) Nerve transmission
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2) Dietary sourcesAbundant plant/animalFresh foods best source
Fresh foods >K than NaProcessed foods >Na than K
3) Dietary RecommendationsMinimal daily requirement 2000mg/day
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Health ConsequencesChronic Deficiency: Hypertension
Low K+ BP: K+ BPAcute Deficiency: Excessive losses
Diuretics, laxative, vomiting & diarrhea
Muscle weakness, paralysis, confusion
ToxicityGenerally excretionInjections fatal: stops heart
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Calcium (Ca2+)
1) FunctionBone metabolism
Strength, rigidity bonesTeeth formation
Body fluids ~1% Ca muscle contraction, clot formation, enzymes, nerve impulses
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2) Absorption & Metabolism~30% absorbed
50% absorbed pregnant women
Factors affecting absorption:Stomach acidityPresence Vit D: Ca binding proteinEqual quantity Phosphorous
Milk good source Phosphorous by Phytate, Fiber
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MetabolismCirculating levels Ca tightly controlled
Hormones, Vit D
Act on:Intestine: or %absorbedBones: or release CaKidneys: or % filtered & excreted
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3) Dietary SourcesDairySmall bones fish/shellfish Nuts, seeds, vegetables, seaweedFortified products: Bioavailability?
4) Dietary Recommendations>19yr 1000mg/day
Women >50yr: 1200mg/day
TUL: 2500mg/day
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Health Consequences – CaDeficiency
Childhood: Stunted growth, Suboptimal bone massAdulthood: Bone loss – OsteoporosisTetany
Toxicity:Constipation Kidney dysfunction, Urinary stonesHardness/stiffness muscles, vascular sys
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Phosphorous1) Functions
85% body phosphorous bone/teethIntracellular bufferActivation enzymes involved energy metabolismPhospholipids –structure, transport
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2) Dietary SourcesProtein rich foods
Legumes, milk, meat
Soft drinks – phosphoric acidFood additives
3) Dietary Recommendations:700 mg/dayTUL: 4000mg/day
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Health Consequences – Phosphorus
DeficiencyVery rare – drug/nutrient interactionBone pain and weakness
ToxicityDecreased blood levels Ca
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Magnesium1) Functions>50% bones, remainder muscle, soft tissue, 1% ECFIn soft tissues: numerous enzymatic systems:
Energy production, transport systemsInhibits muscle contraction/blood clotsImmune system, nerve impulses
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2) Dietary SourcesLeafy vegetables, beans, seeds, nutsWater Intake ~2/3 recommended levels
3) Dietary Recommendations Men 420mg/dayWomen: 320mg/dayTUL:350mg synthetic form only
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Health Consequences - Magnesium
DeficiencyOccurs with disease states
Alcohol abuse, Protein Malnutrition, Kidney, endocrine diseases
Results in:severe tetany, weakness, confusion, hallucinations, convulsions
Toxicity: None known
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Trace Minerals Iron and Zinc
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Iron1) Functions
Oxidation Reduction ReactionsCo-enzymeEnergy yielding reactions
Major component HemoglobinMyoglobin – protein in muscle
Oxygen available muscle contraction
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2) Absorption & Metabolism% absorbed tightly control
requirements % absorbed
Heme: associated heme proteinAnimal foods: 10% dietary intake23% absorbed
Non-heme: no proteinPlant foods: 2-20% absorbed
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Factors effecting absorption1) Form of iron
Heme vs non-heme
2) MFP & Vit Cabsorption non-heme ironConsumed with same meal
Inhibitors1) Phytates/fiber 2) Tannins: Wine, tea, coffee3) Calcium/phosphate in milk
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3) Transport and StorageTransferrin-transportTwo storage proteins
Ferritin - Mainly liverHemosiderin – slower release iron
Daily losesGI tract, bleeding
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Iron RecommendationsMen: 8mg/day, Women: 18mg/day
Ave intake: 10-11mg/dayTUL: 45 mg/day
Food Sources:Emphasize iron rich foods
Meats, Fish, Poultry, Legumes, EggsFortified/enriched wholegrainsDark green vegetables, fruit (dried) useful sources
inhibitors & enhancers
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Health Consequences - Iron
DeficiencyPeople at risk:
Women: menstrual losses, PregnancyInfants, young children, teenagers: needFrequent blood donorsSurgery, trauma
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Iron deficiency prior to anemiaDepleted iron stores concentration, lethargy, mood swings
Iron deficiency anemia - severityLow hemoglobin concentrationRBC pale, small – oxygen cell metabolismFatigue, weakness, headaches, apathy, pallor, poor response cold
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Iron Toxicity1) Hemochromatosis
Iron overload
Occurs:Genetic disorder Repeated blood transfusionMassive dose supplements
Results in: hemosiderin in liver/other tissues
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2) Iron & Heart DiseaseControversialProposed: Iron = oxidant: Oxidised LDL
3) Iron & CancerAlso controversialOxidation DNA
4) Iron PoisoningAccidental poisoning
Vomiting, nausea, rapid heartbeat, dizziness
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Zinc
Distribution 1-2.3gm bodyAll body tissue
Role in bodyMetallo-enzymes
~150 enzymes
Protein, nucleic acid synthesisInsulin synthesisTaste perception
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2) Absorption & excretion
Absorption: 15-40%Upper small intestine
Increased by:Presence amino acids, lactoseLow dietary iron
Decreased by:High phytate, calcium, iron intake Low dietary protein
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Stored with metallothioneinTransport: bound to albumin
3) Dietary Recommendations11mg/day men, 8 mg/day womenTUL: 40mg/day
4) Food Sources: Widely availableGood sources
Meat, animal products, shellfish
Reduced bioavailabilityLegumes, cereals
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Health consequences
1. DeficiencyGrowth retardationHypogonadismDelayed sexual functionImpaired wound healing, immune functionBehavioral disturbances
Accompanies PEMZinc supplementation enhances recovery
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PregnancyAdaptation: absorption, excretion
At risk:Disease patientsPoverty, developing countriesPregnancy, young, elderly
Deficiency due to:intake, needabsorption: high iron, calciumlosses
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2) ToxicityAcute: >25mg/day
Metallic taste, nausea, gastric distress
Chronic toxicity: > RDALDL + HDL = CVD risk copper absorption, copper deficiency
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Other Trace Minerals
Iodine FlourideSelenium ChromiumCopper MolybdenumManganese
Self learning: Use textbook