MINERALS(矿物质)

SECTION5MINERALS（矿物质）一、IntroductionElements（元素）inhumanbody1.TotalelementsInhumanbodyisover80.2.Essentialelementsinhumanbodyover20,mostofthem(about20)aremineralelementsMicroelements:Fe,Zn,Se,I,Cu,Co,Cr,F,Mn,MineralsMo,Si,Ni,B,V.Macroelements:Ca,P,Na,K,Mg,S,Cl.Functionofmineralsinbody1.Compositionofhumanbody.2.MaintainthepHandosmoticpressure(渗透压)ofbodyliquids.3.Regulatingtheexcitingofnerveandmuscle.4.Componentsofprostheticgroup(辅基),hormone,vitamin,protein,nucleicacid,andactivator（激活剂）ofenzyme.5.Theothers二、钙（Calcium）1.DistributionofCalciuminhumanbodyCainthebody:850-1200g1.5%-2.0%ofbodyweightBone,teeth,99%:Hydroxyapatite（羟磷灰石）amorphousCa（未定形钙）Combinedform,0.5%:combinedwithproteinandcitricacid（柠檬酸）Ion,0.5%：MiscibleCaPool（混溶钙池）Inblood,extra-cellularfluid,softtissue,andexchangeable.2.Functionofcalciuminbody1).PrincipalcomponentofskeletaltissueOsteoblasts(成)Osteoclasts(破)BoneCa(miscibleCapool)Children:1-2yearAdult:10-12y(2%-4%peryear,700mg/d)After40y:Cainthebonedecreasedby~1%peryearEarlierinfemalesthaninmales;Mostrapidlyduringfirst3yearsAftermenopause;Tallerpeoplelessrapidly.2).Regulatingneuromuscular(神经肌肉)excitability,maintainingtransmissionofnerveimpulses(神经冲动)andheartbeats.(3)Influencingenzymereaction:Succinodehydrogenase(琥珀酸脱氢酶).Lipase(脂肪酶),ATPase(三磷酸腺苷酶),proteinase(蛋白酶),(4)Others:hormonesecretion,bloodcoagulation(凝结),acid-basebalance,normalcolloid(胶体).3.AbsorptionandMetabolism1)Mechanismofabsorption:Position:inthesmallintestineTranscellular(跨细胞):saturable(可饱和的)(active)transferthatinvolvesacalcium-bidingprotein,calbindin(钙结合蛋白).Paracellular(同细胞水平):anonsaturable(diffusional扩散)transferthatisalinear(一维的)functionofthecalciumcontentofthechyme(食糜).Ca,Pmetabolism2)AffectingfactorsAgechildren:75%0fingestedCa;40%offoodCaadults:30%-60%;20%~70y1/3ofadult’s;15%~SexmalefemalePhysiologicalsituationpregnancyandbreast-feedothersBodyCaconc.DietaryfactorsincreasingCaabsorption:Vit.D,Lactose,Someaminoacids:Arginine(精氨酸),lysine(赖氨酸)decreasingCaabsorption:phytate(植酸盐),oxalate(草酸盐),fibre,fattyacid,alcohol;thyroidhormone(甲状腺素),cortisol(皮质醇),andantibiotics:penicillin,chloramphenical(氯霉素),neomycin(新霉素)膳食成分对钙吸收利用的影响提高吸收利用降低吸收利用无作用乳糖植酸盐磷某些氨基酸膳食纤维蛋白质VitD草酸盐VitC脂肪（脂肪泻时）柠檬酸乙醇果胶3)ExcretionFecalCa:194±73mg/dintheAmericanmenfromunabsorbedCaandendogenous(内源性)CaUrineCa:dietscontaining600-800mg/drangesbetween80-250mginurine.SweatCa:20-30mg/d;1g/dathightemp.MilkCa:150-300mg/dRenaltubularreabsorptionofCaisincreasedbyparathyroidhormone(甲状旁腺素),afallinplasmaCa,metabolicalkolosis(代谢性碱中毒),anddiuretics(利尿剂).Increasedbysalinediureses(含盐多尿症),carbohydrateingestion,phosphatedeprivation(丧失),metabolicacidosis(代谢性酸中毒),cortisal,thyroidandgrowthhormones,dietsrichinproteinandmagnesium(镁).fecalVit.Dandparathyin(甲状旁腺素):renalreabsorption↑Calcitonin(降血钙素):inhibitingbonelossandincreasingurineCa.Calmodulin(钙调节素):regulatingtheCainthecell.4)Biologiccontrolsystemforhomeostasis(体内平衡)ofCa.ECF:ExtracellularfluidCalciumbalanceOnaverage,inatypicaladultapproximately1gofelementalcalcium(Ca2+)isingestedperday.Ofthis,about200mg/daywillbeabsorbedand800mg/dayexcreted.Approximately1kgof(Ca2+)isstoredinboneandabout500mg/dayisreleasedbyresorptionordepositedduringboneformation.Ofthe10gof(Ca2+)filteredthroughthekidneyperdayonlyabout200mgappearsintheurine,theremainderbeingreabsorbed.4.DRIsofCa(1)EstimationofDRIs（膳食参考摄入量）Infants:meanintakeofbreastmilk(母乳)Others:Cabalancetest(平衡试验)Directmeasure(2)DRIs(mg/d)y:0~0.5~1~4~11~18~50~AI:30040060080010008001000Y:pregnantwomenwetnurse（乳母）AI:1000(中期)1200(晚期)1200UL(tolerableupperintakelevel,):2000mgNOAEL:1500mg5.Dietarysourcemilk,smallshrimps(小虾),kelp(海带),legumes(豆类):soybean、blacksoybean(黑豆),redbean(红豆),sesamepaste(芝麻酱),andmanyCasupplements(钙补充剂).常用食物中的钙含量（mg/100g食部）名称含钙量名称含钙量名称含钙量人奶34海带(干)1177蚕豆93牛奶120发菜767腐竹280奶酪590银耳380花生仁67蛋黄134木耳357杏仁(生)140标准粉24紫菜343西瓜子(炒)237标准米10大豆367南瓜子(炒)235虾皮2000豆腐丝284核桃仁119猪肉(瘦)11豆腐240~277小白菜93~163牛肉(瘦)6青豆240大白菜61羊肉(瘦)13豇豆100油菜140鸡肉(瘦)11豌豆84韭菜105三、Iron(铁)1.ironinBodyBodyiron(4-5g)Hemoglobin(血红蛋白)(60%-75%)Myoglobin(肌红蛋白)(3%)Hemeenzymes(含铁酶)Cytochromes(细胞色素)Cytochromeoxidase(细胞色素氧化酶)Peroxidase(过氧化物酶)Catalase(过氧化氢酶)Ferritin(铁蛋白)Hemosiderin(含铁血黄素)4mgastransportironboundtotransferrin(运铁蛋白)intheplasma.Nofreeionofironinthebody.FunctionalFe(75%)StorageFe(25%)ironinBody2.Physiologicfunctions(1)ImportantroleinoxygenandelectrontransportCompositionofhemoglobinandmyoglobin:Oxygentransport.Compositionofenzymes:electrontransport.(2)Others:Catalyzingβ-caroteneVit.A;Promotingproduceofantibody;Lipidstransportinblood;Detoxifying（去毒）:drugsinliverKidneyandRBC3.AbsorptionandMetabolismAbsorptionFe3+Fe2+FoodFeduodenumJejunum空Ileum回colonPlasmairon(~4mg)Fe3++transferrin(35~40mgturnedover/d)StorageFe300~400mgR-Esystem,liver,spleen,bonemarrowBonemarrow20~25mg/dhemoglosinHemoglobincatabolismUrine,sweet,bile,feces(0.5~1mg/d)TransportationUtilizationandconservationStorageHemorrhageRBClostinurine,menstrualloss0.3~1mg/dAllbodycellDeathcellsDesquamation(脱落)ofcells20~25mgExcretionoutlineofironmetabolisminadultIronabsorptionandmetabolis