特殊人群的营养价值

1.NutritionDuringPregnancyThePhysiologyofPregnancyAwoman’sbodyundergoesmanychangesduringpregnancytodevelopandmaintainthesystemsnecessarytosupportthegrowingfetus.HormoneschangesGastrointestinalchangesDelayingastricemptyDecreasedgastricacidityDigestivediscomfortsmorningsickness,heartburnCardiovascularsystemBloodvolumeincreasesby50%IncreaseincardiacoutputDecreaseinalbuminconcentrationRenalfunctionchangesweightgain总体重增加:11~13kg胎儿:3.3kg胎盘、羊水：1.5kg子宫：1.0kg血液：1.2kg乳房：0.4kg细胞间液：1.5kg脂肪：2~4kgRecommendWeightGainDuringPregnancyBMIbeforepregnancyWeightgainUnderweight(BMI19.8)12.5~18.0Normalweight(BMI19.8~26.0)11.5~16.0Overweight(BMI26.0~29.0)7.5~11.5Obesity(BMI29.0)6.0~6.8ThenutritionalneedsofpregnancyDuringpregnancy,awoman’snutrientintakeandbodystoresmustprovideallthenutrientsneedstosupportthegrowthanddevelopmentofthebabywhilecontinuingtomeetthemother’sneeds.EnergyAtypicalpregnancyhasbeenestimatedtorequireanadditional55000kcalories.Additional200kcal/dayduringthesecondandthirdtrimesters.ProteinProteinneedsarealsoincreasedduringpregnancytoprovideforRNI:+5g/d1sttrimester+15g/d2ndtrimester+20g/d3rdtrimesterMineralsCalciumPregnantwomenabsorbmoreofthecalciumtheyconsumeandloselesscalciumintheurinethandononpregnantwomen.Thefetusretainsabout30gramsofcalciumoverthecourseofgestation.Mostofthecalciumisdepositedinthelasttrimesterwhenthefetalskeletonisgrowingmostrapidlyandtheteethareforming.RNI800mg1sttrimester1000mg2ndtrimester1200mg3rdtrimesterfoodsource:milkanddairyproductsIronIrondeficiencyanemialowbirthweightpretermdeliveryBabiesbornprematurelymaynothavehadtimetoaccumulatesufficientiron,butbabiesbornattermusuallyhaveadequateironevenifthemotherisdeficient.RNI15mg1sttrimester25mg2ndtrimester35mg3rdtrimesterfoodsource:redmeats,leafygreenvegetables,fortifiedcerealsironsupplementZincZincdeficiencyduringpregnancyisassociatewithanincreasedriskoffetalmalformationandlowbirthweight.RNI11.5mg/d1sttrimesrer16.5mg/d2ndtrimester16.5mg/d3ndtrimesterIodineIodinedeficiencyduringpregnancyincreasestheriskofstillbirthspontaneousabortionandcanresultinconditionintheoffspringcalledcretinism(呆小病）.RNI200μg/dFolicAcidandVitaminB12FolicacidandvitaminB12areessentialforcelldivision,Adequatefolateintakesiscrucialevenbeforeconceptionbecauserapidcelldivisionoccursinthefirstdaysandweeksofpregnancy.Folateisbelievedtobeessentialforproperformationofneuraltube.DeficienciesoffolateandvitaminB12canalsoresultinmegaloblasticanemia.Vitaminsmegaloblasticanemia:reticulocytescellsmustbeconstantlyreplenishedvianewsynthesisofDNAandRNAVitaminAHighdietaryintakesofpreformedvitaminA(10,000IU)cancausebirthdefectsinhumansandanimals.VitaminDVitaminCMaternalMalnutritionandPregnancyOutcomeLowbirthweightPrematureIntrauterinegrowthretardationStillbirthIncreasedearlynewborndeathsMalformationThephysiologyoflactation2.NutritionrequirementonLactationMaternalNutrientNeedsduringlactationTheneedforenergyandmanynutrientisevengreaterduringlactationthanduringpregnancy.Thisisbecausethemotherisstillprovidingforallofthenutrientneedsofinfantwhoisgrowingfasterandismoveractivethenthefetus.EnergyContainedinthemilkitselfNeededtosynthesizethecomponentsofthemilkRNI:+500kcalProteinTheproteinneededtoproducemilkincreasematernalproteinneedsRNI+20gWaterWhenfluidintakeislow,themother’surinewillbecomemoreconcentratedtoconservewaterformilkproduction.Toavoiddehydrationandensureadequatemilkproduction,fluidintakshouldbeincreasedbyabout1L/d.RNIsofsomeelementandvitamineslactationpregnantnon-pregnantCalcium1200mg1200mg800mgIron25mg35mg20mgVit.A1200µg700µg700µgVit.B11.8mg1.5mg1.3mgVitB21.7mg1.7mg1.2mgEnergy1.Basalmetabolicrequirement2.Specificdynamiceffect3.Physicalactivity4.Tissuegrowth5.Fecalloss3timesgreaterthaninadults,85~95kcal/kg40~50%comefromfathighenergydensitysmallstomachimportantfornervoussystemdevelopment3.InfantnutritionProteinTissuegrowth1.6~2.2g/kgTotalproteinintakeshouldnotexceed20%ofenergyneeds.Fatenergy/%0~0.5year：45%~50%0.5~:35%~40%EFAdevelopmentofnervoussystemMineralsandVitaminsSpecialemphasisoncalciumandironIronIron-fortifiedinfantformulasIron-fortifiedcerealWaterNeedgreaterthanthatofanadultInfant120~150ml/kg/dayBreastFeedingNutritionalQualitiesofHumanMilk•Humanmilkisverydifferentincompositionfromcow’smilk•Unlessaltered,cow’smilkshouldnotbeusedininfantfeedinguntiltheinfantis12monthsold.2.compositionofbreastmilkproteinapproximate1/3asincow’smilkwheyproteins:casein=80:20(18:20incow’s)smallerandmoreflocculentcurdeasierdigestion,greaterabsorption,softstoolslipidsmostvariablemacronutrientinhumanmilkfineemulsificationactivelipasehigherdegreeofunsaturationcarbohydratelactoseishigherlowerintestinalPHimprovetheabsorptionofnitrogen,calciumandmagnesiumencouragesthegrowthoffermentativeratherthanputrefactivebacteriacomponentsofmyelinandcollagenmineralscalcium:phosphorus2:1(1:1incow’smilk)copperishigherironisslightlyhigher,utilizedmoreefficientlyvitaminstwiceasmuchvitaminAandniacinfourtimesasmuchasascorbicacidandvitEvitaminDislowImmunefactorS-IgA免疫球蛋白Lactoferrin乳铁蛋白Lact