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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

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