MineralsWord格式.docx
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iodine碘I、zinc锌Zn、selenium硒Se、copper铜Cu、molybdenum钼Mo、chromium铬Cr、cobalt钴Co、iron铁Femanganese,fluoride,silicon,tin,arsenic,nickel…
Presentinbodytissuesatconcentrations<
Essentialmicrominerals(8):
iodine碘I、zinc锌Zn、selenium硒Se、copper铜Cu、molybdenum钼Mo、chromium铬Cr、cobalt钴Co、iron铁Fe
Potentialtoxicmicro-minerals:
铝Al、锡Sn、锂Li、铅Pb、镉Cd、汞Hg、砷As
FunctionofMinerals
1.partoftherigidbodystructureandsoftbodytissue
如钙、磷、镁是骨骼和牙齿的重要成分,磷、硫是构成组织蛋白的成分。
boneisCa3(PO4)2,CaCO3andMg3(PO4)2arethemajoringredientsofbone,teeth;
phosphorusandsulfurarethecomponentsofprotein.Softtissueincludesskin,fibroustissues,fat(whichareconnectivetissue),andmuscles,nervesandbloodvessels(whicharenotconnectivetissue).
2.partofbodyfluids(fluidsoutsideofcells);
Na+,K+,andCl-(chlorine)arepresentasionsandpreservetheelectrolytebalanceinourbodies.
3.Keepbalanceoffluid’spHvalue
酸性、碱性无机离子的适当配合,加上重碳酸盐和蛋白质的缓冲作用是维持机体酸碱平衡的重要机制。
4.Keepingneuron,musclesexciting
在组织液中的各种无机离子,特别是保持一定比例的钾、钠、镁、钙离子是维持神经、肌肉兴奋性,细胞膜通透性以及所有细胞正常功能的必要条件。
5.Partofimportantphysiologicalbioactivecomponentsinbody
无机元素是构成某些具有特殊生理功能的物质的重要成分。
如血红蛋白和细胞色素系统中的铁,甲状腺素中的碘和谷胱甘肽氧化物酶中的硒。
6.Someparticipatewithenzymesinmetabolicprocesses(cofactors)
无机离子是很多酶系统的活化剂、辅因子或组织成分。
如盐酸之于胃蛋白酶原,氯离子之于唾液淀粉酶,镁离子之于氧化磷酸化的多种酶类,以及很多其他含金属的酶类。
Absorption&
RegulationofMinerals
Absorption
Smallintestine&
largeintestine
Regulation
Kidneys&
smallintestine
Thebioavailabilityofamineralmaybeinfluencedbyavarietyoffactors:
1.Thechemicalformwilldeterminehowreadilyourbodiesabsorbthemineral.Ahighlystablechelateformwouldbepoorlyabsorbedcomparedtofreeionsthatarereadilyabsorbed.Phytate(植酸盐)andoxalate(草酸盐),foundinsomefoods,reducetheabsorptionofcalcium,ironandzinc.Iodineabsorptionmaybehinderedbynitrates(硝酸盐).
But,ligands配位体thatformsolublechelateswithmetalswillenhanceabsorption.
Incontrast,ironabsorptionmaybeincreasedwhenvitaminCisconsumedduringthesamemeal.
2.InteractionswithothermineralsInhighconcentrations,somemineralsmayactuallyinhibittheabsorptionofanothermineral.Theabsorptionofironisinhibitedbyhighconcentrationsofcalcium,andtoomuchironitselfmayleadtopoorzincabsorption.
3.Requirement,Theamountofamineralpeopleactuallyabsorbcanvary,andwilldependupontheirownneeds,andhowmuchtheyalreadyhaveofthatnutrientinthebody.
Mineralsarefairlystableinnormalfoodprocessingconditions.
Calcium
Mostabundantmineralinanimaltissues
99%Cainboneandteethskeleton
Ca(PO4)285%;
CaCO310%
1%presentinBlood&
othertissuesCalledmisciblecalciumpool(混溶钙池)
Lotsoffunctions
Bone,teethstructure
Nervefunction
Musclecontraction
Bloodclotting
Decreasepenetrationofcapillaryvesselandmembrane
FoodSources
1.MilkanddairyproductsHighamountsHighbioavailability(fortifiedwithvitaminD)
2.GreenleafyvegetablesPoorabsorption
3.Fishbones
4.Fortifiedjuice/cereal
CalciumAbsorption
DependentonVitaminD
Cabindingproteininintestinalepithelialcell
Absorptiondependsonneed
Particularlyhighduringgrowth,pregnancyandlactation
Bioavailabilitydecreasedby
Phytates(grains)
Oxalates
Wheatbranhigherfiber
Lowestrogen雌激素levels(postmenopausalwomen)
CalciumRegulation
Threehormonesinvolvedinregulation
1.VitaminD3fromkidney
2.Parathyroidhormone(PTH)fromparathyroidgland
3.Calcitoninfromthyroidgland
PTHandVitaminD3acttoincreaseplasmaCa,whilecalcitoninactstodecreaseplasmaCa
HormonalControlSystems
Maintainingnormalbloodcalciumandphosphorusconcentrationsismanagedthroughtheconcertedactionofthreehormonesthatcontrolfluxesofcalciuminandoutofbloodandextracellularfluid:
Parathyroidhormoneservestoincreasebloodconcentrationsofcalcium.
1.Increasesboneresorptionbyactivatingosteoclasticactivity
2.Increasesrenalcalciumreabsorptionbythedistalrenaltubules
3.Increasestheformationof1,25-dihydrocholecalciferolbyincreasingtheactivityofalpha-hydroxylsinthekidney
VitaminDactsalsotoincreasebloodconcentrationsofcalcium.Itisgeneratedthroughtheactivityofparathyroidhormonewithinthekidney.
1.Enhancescalciumabsorptionfromtheintestine
2.Facilitatescalciumabsorptioninthekidney
3.Increasesbonecalcificationandmineralization
4.Inexcess,mobilizesbonecalciumandphosphate
CalcitoninisahormonethatfunctionstoreducebloodcalciumlevelsCalcitoninisa32aminoacidpolypeptidesecretedbytheparafollicularcellsinthethyroidgland.Ittendstodecreaseserumcalciumconcentrationand,ingeneral,haseffectsoppositetothoseofPTH.
Suppressionofrenaltubularreabsorptionofcalcium.Inotherwords,calcitoninenhancesexcretionofcalciumintourine.
Inhibitionofboneresorption,whichwouldminimizefluxesofcalciumfromboneintoblood.
ResponsestoLowBloodCalcium
Parathyroidhormone(PTH)released
StimulatesconversionofinactiveformofvitaminDtocalcitrol
Increasesinbloodcalcium
Smallintestine
Resorptionatkidneys&
blood
CalciumDeficiencies
1.Ricketsingrowingchildren
2.Osteomalacia(osteoporosis)inadult
CalciumandOsteoporosis
Aroundage40,bonebreakdownexceedsformation.
Ideally,wantveryhighbonemasswhenthisbegins.
Byage65,somewomenhavelost50%ofbonemass.
CalciumToxicity
1.About90%ofallhypercalcemiacasesaretheresultofhyperparathyroidism,aconditioninwhichparathyroidhormonesareproducedinexcess.
2.Increasetherisksofkidneystone肾结石
3.Milk-AlkaliSyndrome,MAS(乳碱综合症):
symptomsincludehypercalcemia(高钙血)、alkalosis(碱中毒)和renaldysfunction(肾功能障碍)。
乳碱综合症是指因长期进食大量牛奶或钙剂,并服用大量可吸收的碱剂引起的高钙血症、碱中毒及不同程度的肾功能损害等一组临床症候群。
过去多发生在消化性溃疡患者的内科治疗中,因治疗方案的改进,如服用不溶性碱性药物,本征现已罕见。
4.Overtakeofcalciumcandisturbtheintakeofotherminerals.Iron,zinic,magnasium,andphosphorus
Phosphorous
人体内第二大元素,在成人体内含量为400-500g左右,占体重1%左右,占体内无机盐总量的1/4
Functions
1.Componentofbone,teethskeleton
2.Componentofprotein,DNAandRNA
3.Vitallyimportantinenergymetabolism
ATP
creatinephosphate磷酸肌酸磷酸肌酸是在肌肉或其他可兴奋性组织(如脑和神经)中的一种高能磷酸化合物,是高能磷酸基的暂时贮存形式,能在肌酸激酶的催化下,将其磷酸基转移到ADP分子中。
当一些ATP用于肌肉收缩,就会产生ADP。
这时,通过肌酸激酶的作用,磷酸肌酸很快供给ADP以磷酸基,从而恢复正常的ATP高水平。
由于肌肉细胞的磷酸肌酸含量是其ATP含量的3~4倍,前者可贮存供短期活动用的、足够的磷酸基团。
在活动后的恢复期中,积累的肌酸又可被ATP磷酸化,重新生成磷酸肌酸,这是同一个酶催化的相反的反应。
因为细胞中没有其他合成和分解磷酸肌酸的代谢途径,此化合物很适合完成这种暂时贮存的功能。
4.Asacoenzymeinmetabolicsystem(TPP,FAD,NAD+)
5.MaintenanceofbloodpH(phosphatebuffer)
Metabolism&
RegulationofPhosphorusintheBody
VitaminD-dependentactivetransport
Simplediffusion
Concentrationscontrolledby:
Calcitriol,PTH,calcitonin
Excretedbykidney
BioavailabilitycouldbeimprovedifphytatePcanbereduced.FermentationofflourcouldreducephytatePcontent.食物中的磷以有机磷和无机磷两种形式存在,有机磷主要是蛋白质和磷脂类,无机磷主要是谷类和蔬菜中以植酸形式存在的磷,不易被人体吸收。
MainsourceofPingrain
Deficienciesinclude
Ricketsorosteomalacia
Pica异食癖(depravedappetite)–chewingofwood,bones
Lowfertilityorgrowth
PhosphorusToxicity
Overtakeofphosphoruscancausehyperphosphatemia高磷血症是慢性肾脏病(CKD)的常见并发症,是肾功能衰竭排磷困难引起继发性甲状旁腺功能亢进、钙磷乘积变化、维生素D代谢障碍
三、钾(potassium)
FunctionsofPotassiumintheBody
1.Fundamentalfornormalnerveandmusclefunctionespeciallycriticalintherightamountforregulatingnervetransmissionsandmusclecontractions,whichinvolvestheinterchangeofpotassiumandsodiuminandoutofnerveandmusclecells
2.Neededformetabolismofcarbohydratesandproteins..EssentialforproteinandnucleicacidsynthesisinvolvedinsynthesisofproteinfromaminoacidsConvertsglucoseintoglycogen(musclefuel)neededformetabolismandstorageofcarbohydratesforuseasenergybythemuscles
3.Regulatesheartfunctionneededforheartfunctionandrhythm,andhelpstreatheartdisorders.adietcomprisinghighpotassiumfoodslowersriskofstrokeandheartattackbyupto40%.
4.Requiredfornormalfluidbalanceactswithsodiumtocontrolthebody'
swaterbalance
5.maintainacid/alkalibalancehelpsregulatethebody'
selectrolyteandacid-alkaline(pH)balance
6.Reducesbloodpressurehelpsthebodyhandlesodiumandsoreduceriskofhighbloodpressure
7.preventsosteoporosisstudiesalsoshowacorrelationbetweenbonemineraldensityandintakeofpotassium-richfoodsthathelptomaintainthebody'
spH(acidalkaline)balancesothatlesscalciumneedstobemobilizedfrombonetodoso,whichpreservesbonestrengthandpreventsosteoporosis.
8Importantroleinkidneyfunctionpotassiumcitrateisknowntodissolvecalciumandsohelppreventformationofkidneystonesandcalcificationofsofttissues.largescalestudieshaveshownthatthosewhofollowtheRDAandt