https://ebookmass.com/product/the-vitamins-fundamentalaspects-in-nutrition-and-health-6th-edition-gerald-f-combs-
Instant digital products (PDF, ePub, MOBI) ready for you
Download now and discover formats that fit your needs...
The Vitamins, Fifth Edition: Fundamental Aspects in Nutrition and Health Gerald F. Combs Jr.
https://ebookmass.com/product/the-vitamins-fifth-edition-fundamentalaspects-in-nutrition-and-health-gerald-f-combs-jr/
ebookmass.com
Nutrition for Health and Health Care 6th Edition, (Ebook PDF)
https://ebookmass.com/product/nutrition-for-health-and-healthcare-6th-edition-ebook-pdf/
ebookmass.com
Diet and Nutrition Sourcebook (Health Reference), 6th Edition Kevin Hayes
https://ebookmass.com/product/diet-and-nutrition-sourcebook-healthreference-6th-edition-kevin-hayes/
ebookmass.com
Measuring the Business Value of Cloud Computing 1st ed. Edition Theo Lynn
https://ebookmass.com/product/measuring-the-business-value-of-cloudcomputing-1st-ed-edition-theo-lynn/
ebookmass.com
Electrocardiography in ischemic heart disease clinical and imaging correlations and prognostic implications Second Edition Bayés De Luna
https://ebookmass.com/product/electrocardiography-in-ischemic-heartdisease-clinical-and-imaging-correlations-and-prognostic-implicationssecond-edition-bayes-de-luna/
ebookmass.com
Plasticenta: First evidence of microplastics in human placenta Antonio Ragusa
https://ebookmass.com/product/plasticenta-first-evidence-ofmicroplastics-in-human-placenta-antonio-ragusa/
ebookmass.com
The PayTech Book: The Payment Technology Handbook for Investors, Entrepreneurs, and FinTech Visionaries Markos
Zachariadis
https://ebookmass.com/product/the-paytech-book-the-payment-technologyhandbook-for-investors-entrepreneurs-and-fintech-visionaries-markoszachariadis/
ebookmass.com
Additive Manufacturing 1st Edition Juan Pou Antonio Riveiro Paulo Davim
https://ebookmass.com/product/additive-manufacturing-1st-edition-juanpou-antonio-riveiro-paulo-davim/
ebookmass.com
Diversity and Cultural Competence in Health Care: A Systems Approach 1st Edition – Ebook PDF Version
https://ebookmass.com/product/diversity-and-cultural-competence-inhealth-care-a-systems-approach-1st-edition-ebook-pdf-version/
ebookmass.com
A Lves
https://ebookmass.com/product/ethnozoology-animals-in-our-lives-romulo-r-omeu-n-obrega-a-lves/
ebookmass.com
TheVitamins Thispageintentionallyleftblank
TheVitamins FundamentalAspectsinNutritionandHealth SixthEdition GeraldF.Combs,Jr.
ProfessorEmeritus,CornellUniversity,Ithaca,NY,UnitedStates
SeniorScientist,JeanMayerUSDAHumanNutritionResearchCenteronAging,TuftsUniversity, Boston,MA,UnitedStates
JamesP.McClung
Westborough,MA,UnitedStates
AcademicPressisanimprintofElsevier 125LondonWall,LondonEC2Y5AS,UnitedKingdom 525BStreet,Suite1650,SanDiego,CA92101,UnitedStates 50HampshireStreet,5thFloor,Cambridge,MA02139,UnitedStates TheBoulevard,LangfordLane,Kidlington,OxfordOX51GB,UnitedKingdom
Copyright © 2022ElsevierInc.Allrightsreserved.
Nopartofthispublicationmaybereproducedortransmittedinanyformorbyanymeans,electronicormechanical,including photocopying,recording,oranyinformationstorageandretrievalsystem,withoutpermissioninwritingfromthepublisher. Detailsonhowtoseekpermission,furtherinformationaboutthePublisher’spermissionspoliciesandourarrangements withorganizationssuchastheCopyrightClearanceCenterandtheCopyrightLicensingAgency,canbefoundatourwebsite: www.elsevier.com/permissions
ThisbookandtheindividualcontributionscontainedinitareprotectedundercopyrightbythePublisher(otherthanasmay benotedherein).
Notices
Knowledgeandbestpracticeinthis fieldareconstantlychanging.Asnewresearchandexperiencebroadenourunderstanding, changesinresearchmethods,professionalpractices,ormedicaltreatmentmaybecomenecessary.
Practitionersandresearchersmustalwaysrelyontheirownexperienceandknowledgeinevaluatingandusingany information,methods,compounds,orexperimentsdescribedherein.Inusingsuchinformationormethodstheyshouldbe mindfuloftheirownsafetyandthesafetyofothers,includingpartiesforwhomtheyhaveaprofessionalresponsibility.
Tothefullestextentofthelaw,neitherthePublishernortheauthors,contributors,oreditors,assumeanyliabilityforany injuryand/ordamagetopersonsorpropertyasamatterofproductsliability,negligenceorotherwise,orfromanyuseor operationofanymethods,products,instructions,orideascontainedinthematerialherein.
LibraryofCongressCataloging-in-PublicationData
AcatalogrecordforthisbookisavailablefromtheLibraryofCongress
BritishLibraryCataloguing-in-PublicationData
AcataloguerecordforthisbookisavailablefromtheBritishLibrary
ISBN:978-0-323-90473-5
ForinformationonallAcademicPresspublicationsvisitourwebsite at https://www.elsevier.com/books-and-journals
Publisher: NikkiP.Levy
AcquisitionsEditor: MeganBall
EditorialProjectManager: LindsayC.Lawrence
ProductionProjectManager: KumarAnbazhagan
CoverDesigner: MatthewLimbert
TypesetbyTNQTechnologies
Tothestudentsandprofessionalswhowillusethisbook,tothose whohaveusedpreviouseditions,andtothosewhoseinsights havehelpedusproducethissixthedition;
ToMr.Cooper;and ToPapa,theoriginal‘Dr.McClung’
theAuthors Thispageintentionallyleftblank
Generalpropertiesofvitamins
Vitamindeficiency
7. VitaminE VitaminD 12. Niacin 13. VitaminB6 8.BiomarkersofvitaminB6
11.OtherrolesofvitaminB6
14. Biotin
8.Biomarkersofpantothenicacidstatus
10.Pantothenicaciddeficiency
12.Pantothenicacidtoxicity
16. Folate
17. VitaminB12 5.VitaminB12
6.VitaminB12 metabolism
18. Quasi-vitamins 7.MetabolicfunctionsofvitaminB12
8.BiomarkersofvitaminB12
9.VitaminB12
516
status 516
11.OtherrolesofvitaminB12 inhealth anddisease 518 Neuropathicpaintherapy 518 Cyanidebinding 518
12.VitaminB12 toxicity 519 13.Casestudies 519 14.Chapterquiz 521
5.Ubiquinones 551
Recognitionofnutritionalrolesof ubiquinones 551
Chemicalnatureoftheubiquinones 551
Conditionsofneedfordietary ubiquinones 552
Conditionslimitingubiquinone biosynthesis 552
Conditionsincreasingubiquinoneneed 553
Dietarysourcesofubiquinones 553
Absorptionandtransportofubiquinones 553
Metabolismofubiquinones 554
Metabolicfunctionsofubiquinones 555
Physiologicaleffectsofubiquinones 555
Biomarkersofubiquinonestatus 557
Safetyofubiquinones 557
6.Lipoicacid 557
Chemicalnatureoflipoicacid 557
Conditionslimitinglipoicacid biosynthesis 558
Dietarysourcesoflipoicacid 558
Absorptionandtransportoflipoicacid 558
Metabolismoflipoicacid 559
Metabolicfunctionsoflipoicacid 559
Physiologicalfunctionsoflipoicacid 560
Biomarkersoflipoicacidstatus 561
Safetyoflipoicacid 561
Beneficialbioactivefactors 561
7.NonprovitaminAcarotenoids 561
BenefitsofnonprovitaminAcarotenoids 561
ChemicalpropertiesofnonprovitaminA carotenoids 561
DietarysourcesofnonprovitaminA carotenoids 562
Absorptionandtransportof nonprovitaminAcarotenoids 562
MetabolismofnonprovitaminAcarotenoids 565
MetabolicfunctionsofnonprovitaminA carotenoids 566
PhysiologicalfunctionsofnonprovitaminA carotenoids 566
BiomarkersofnonprovitaminAcarotenoid status 571
Recommendedintakes 571
SafetyofnonprovitaminAcarotenoids 572
8.Flavonoids 572
Recognitionofnutritionalrolesof flavonoids 572
Benefitsofdietaryflavonoids 573
Chemicalpropertiesofflavonoids 573
Dietarysources 574
Absorptionandtransportofflavonoids 576
Metabolismofflavonoids 576
Metaboliceffectsofflavonoids 577
Enzymemodulation.flavonoidscan affecttheactivitiesofmanyenzymes 577
Physiologicaleffectsofflavonoids 578 Biomarkersofflavonoidstatus 583 Flavonoidsafety 583
9.Unidentifiedfactors 584 10.Casestudies 584
11.Chapterquiz 587 Recommendedreading 587
PartIII 19. Sourcesofthevitamins Anchoringconcepts 593
3.Vitaminlossesinfoods 601
4.Addingvitaminstofoods 603 Purifiedvitamins 603
604
605 Additionofvitaminstofoods 605 Stabilitiesofvitaminsaddedtofoods 606
5.Biofortification 606
6.Vitaminlabelingoffoods 609
7.Vitaminsinhumandiets 609
Vitaminintakesfromfoods 610
Vitaminsinbreastmilkandformula foods 611
8.Vitaminsupplementation 615
Guidelinesforsupplementuse 615
9.Vitaminsinlivestockfeeding 617
Vitaminsinanimalfeeds 617
Lossesofvitaminsfromfeedstuffsand finishedfeeds 618
Vitaminpremixesforanimalfeeds 619
Stabilitiesofvitaminsinfeeds 620
20. Assessingvitaminstatus
22. Vitaminsafety 2.Biomarkersofvitaminstatus 628
3.Vitaminstatusofhumanpopulations 632
4.Globalundernutrition 637
21. Vitaminneeds
1.Dietarystandardsforvitamins 644
4.Casestudies
Thispageintentionallyleftblank
PrefacetotheSixthEdition Understandingthevitaminsisfundamentaltounderstanding nutrition.Thehistoryoftheirdiscoveryandthecontinuing elucidationoftheirrolesinhealthisthehistoryofthe emergenceofnutritionalscienceoutoftheareasofphysiology,biochemistry,medicine,andagriculture.Thepractical applicationofthatknowledgedrawsonfoodscience, medicine,publichealth,economics,sociology,andagriculture.Capturingtheunderstandingandcontemporaryrelevancethatwasproducedbythathistoryandavailablefor contemporaryapplicationisaformidablechallenge.Itisalso aprivilege.Forusasauthors,thattaskhasinvolvedyearsof reviewingthousandsofpublications,andmonthsoflooking forwaystopresentthatcomplexinformationclearlyand withneitheroversimplificationnoroverstatement.
Producingthissixtheditionof “TheVitamins” benefittedfromthecombinedperspectivesofanacademic whoconceivedtheprojectmorethan30yearsagoandused thebookinhisteachingatCornellUniversity,withthoseof researchscientistwhostudiedthe first fi rsteditionasa graduatestudentattheUniversityofNewHampshireand, then,latereditionsasastudentandteachingassistantat CornellUniversity.Webelievethatthedynamicrelationshipwehaveenjoyedformanyyears asstudent/mentor, colleagues,friends,andcoauthors hasfacilitatedour producingthemostcompleteandup-to-dateeditionofthis text,suchthatitwillbeusefulasacontemporaryreference aswellasateaching/learningaid.
Inwritingthissixtheditionof “TheVitamins,” wewere aidedbyhelpfulinsightsfromusersofpreviouseditions. Thosepromptedustomakeseveralchangesthatwebelieve enhanceitsutility:reorganizationofsomechapters;expanded discussionsofthephysiologicalfunctionsofvitamins,andon thequasi-vitamins;increasedfocusonthecurrentknowledge ofthevitamincontentsofbreastmilk;increasednumbersof citationstorecentscientificpublications;anddoublethe numberofcasestudies.Wehavealsoaddedfeaturesto facilitateself/on-linestudy: “keypoint” highlights,chapter quizzes,andanappendedlistofexamination-typequestions.
Wearegratefulforthehelpofourfriendsandcolleagues, Dr.DanRaiten,Dr.J.ThomasBrenna,andDr.XingenLei. WealsoappreciatetheprofessionalassistanceofMs.Kumar Anabazhagan,Ms.LindsayLawrence,andMs.MeganBallof Elsevier,Inc.
Weenjoyedwritingthissixtheditionof TheVitamins. Wehopeyouwillenjoyreadingitand,mostofall, fi ndit useful.
GeraldF.Combs,Jr. Topsham,Maine JamesP.McClung
Westborough,Massachusetts
June10,2021
HOWTOUSETHISBOOK TheVitamins isintendedasbothareferencebookanda teachingtext.Inwritingit,wehadtwoaudiencesinmind.
TOTHEHEALTHPROFESSIONAL TheVitamins isdesignedasaone-stopsourceofcomprehensivecontemporaryinformationaboutthevitamins suitedforaprofessional’sbookshelf.Init,youwill find informationonthefollowing:
l the HistoryofVitaminDiscovery,whichrevealsthe disparateactivitiesofpeoplewiththetoolsandunderstandingsofanearliertimewhowereabletoseein diet-relatedphenomenapossibilitiesthatothershad missed;
l ChemicalPropertiesoftheVitamins,theirisomers andmetabolites,whichprovidesabasisforunderstandingtheirfunctionsinanimalsandtheirfoods;
l UtilizationandMetabolismoftheVitamins,which informstheirvaryingpotenciesandbiologicalactivities;
l ConsequencesoftheirDeficientandExcessive Intakes,whichinformsthephysiologicalimportof achievinghealthfulintake;
l available Biomarkers,whichprovidetoolsfor diagnosingvitaminstatus;and
l OtherHealthRolesofVitamins beyond preventionof theirtraditionaldefi ciencydisorders,someofwhich maysurpriseyou.
Throughoutthebook,youwillalso findexamplesof bothclassicalandcurrentresearch findingsaswellas footnoted citationstokeypublications inthescientific literature.Inthissixthedition,weincluded complete
citations tomakeiteasierforthereadertodetermine whethertosearchthoseoriginalreportsorreviews. TheAppendiceswillbeaseasyreferencestothevitamin contentsofafoodsandfeedstuffs.
Weareatyourserviceforquestionsregardingthis editionandwelcomeyourinsightsthatmayenhancefuture editionsof TheVitamins.Wewouldalsobegratefulto learnaboutwaysyouhaveusedthisvolumetoextendand shareyourpersonalknowledgeofthevitamins.
TOSTUDENTSANDINSTRUCTORS TheVitamins isalsointendedasateachingtextforan upper-level/graduatestudywithinNutritionorHealthrelatedcurricula.Itwillbeusefulinbothtraditionaland virtualclassroom,aswellasself-pacedlearningformats.It hasseveralfeaturesdesignedtoenhanceitsutilityfor teachersandlearners:
l AdvanceOrganizers: EachchapteropenswithstatementsofAnchoringConcepts,LearningObjectives, andVocabularytolookfor(astheyaredefinedin context).
l ScannableLayout: Theextensiveuseofsectionheadingsandsubheadersisdesignedtofacilitatescanning topreparethereaderforthematerialandtohelpher/ him findmaterialofspecialinterest.
l PlannedRedundancy: Toenhanceretention,crosscuttingissuesareaddressedinmultipleformats throughoutthebook.
l KeyPoints: Concisesummariesofmajorissuesoccur throughouteachchapter.
l CaseStudies: Presentationsofrelevantcasesfromthe clinicalliterature,followedbyDiscussionQuestions toprovokethinkinganddiscussionaboutvitamin function.
l ExtensiveFootnotes: Citationstokeyresearchpapers andreviews,usefulinpursuinginformationatdeeper levelsthancoveredinthetext.
l ChapterQuizzes: Summaryquestionstodirect thinking/discussionaboutkeylearningsfromeach chapter.
l RecommendedReading: Usefulreviewstofacilitate follow-upstudyofthechaptersubjectmatter.
l FinalExamQuestions: Aslateofquestionsofthetype usedina finalexamtestingknowledgeoftherolesof vitaminsinnutritionandhealth.
Tothestudent. Whenyouusethistext,makesureto havebyyoursideanotebook,pencil(notpen youmay wanttomakechangesinthenotesyoutake).Before readingeachchapter,takeafewmomentstogooverthe AnchoringConceptsandLearningObjectivesonthe chaptertitlepage.Thoseinthe firstseveralchaptersshould alreadybefamiliartoyou;ifnot,thenitwillbenecessary
foryoutodosomebackgroundreadingordiscussionuntil youfeelcomfortableinyourunderstandingofthesebasic ideas.Youwill findthatmostchaptersbuilduponthe understandinggainedthroughpreviouschapters;inmost cases,the AnchoringConcepts ofachapterrelatetothe LearningObjectives ofpreviouschapters.Payattentionto the LearningObjectives;theyarethekeyelementsofunderstandingthatthechapterisintendedtosupport.Keeping theminmindasyougothrougheachchapterwillhelpyou maintainfocusonthoseelements.Next,readthroughthe Vocabularylistand mark anytermsthatareunfamiliaror aboutwhichyoufeelunsure.Then,makealistof yourown questions aboutthetopicofthechapter.
Asyoureadthroughthetext,lookforitemsrelatedto yourquestionsandforunfamiliarterms.Youwillbeableto findkeytermsinbold-facetype,andyoushouldbeable togetagoodfeelfortheirmeaningsfromthecontextsof theiruses.Ifthisisnotsuffi cientforanyparticularterm, thenlookitupinamedicaldictionary.Don’twaittodo this.Cultivatethehabitofbeingbotheredby not understandingsomething thiswillhelpyouenormouslyin yearstocome.
Asyouproceedthroughthetext,notewhatinformation thelayoutisdesignedtoconvey.First,notethatthemajor sectionsofeachchapterareindicatedwithaboldheading. Thisisdonetohelpyou scan forparticularinformation. Alsonotethatthefootnotedinformationislargelysupplementaryandnotessentialtotheunderstandingofthe keyconceptspresented.Therefore,thetextmaybereadat twolevels:atthebasiclevel,oneshouldbeabletoignore thefootnotesandstillgetthekeyconcepts;atthemore detailedlevel,oneshouldbeabletopickupmorebackground,particularlykeycitationstotheprimaryliterature, fromthefootnotes.Referbackfrequentlytoyourownlist ofquestionsand “target” vocabularywords;whenyou fi nd ananswerorcanmakeadeduction,makeanote.Don’t hesitatetowriteinthebook,particularlytoputaconcept intoyourownwords,ortonotesomethingyou find importantordon’tfullyunderstand.Studiesshowthattobe aneffectivelearningtechnique.Whenyouhavecompleted achapter,takesometimetolistwhatyouseeasthe keypoints thosethatyouwouldcoverinaformal presentation.Then,skimbackoverthechapter.
You’ll findthat Chapters5 22 eachhaveoneormore casestudiesbasedonactualclinicalcasereportsabstracted fromthescientifi cliterature.Foreach,usetheassociated questionstofocusyourthinkingonthefeaturesthatrelate tovitaminfunctions.Asyoudoso,trytoignorethe obviousconnectionwiththesubjectofthechapter;put yourselfinthepositionofsomeonecalledupontodiagnose theproblemwithoutpriorknowledgeofitinvolvinga nutrient.TheCaseStudyin Chapter19 isdifferent;itisa fictionalbuthighlyplausiblescenariothatcallsfor anonobviousdecision.
TakesometimeandgothroughtheChapterQuizatthe endofeachchapter.Thesequestions,too,aredesignedto directyourthinkingbacktothekeyconceptsofthe respectivechapter,andtofacilitateintegrationofthose conceptswiththoseyoualreadyhave.Wehavemadea pointin Chapter1 ofusingthetechniqueof concept mapping toillustratetheintegrationofcomplexsubject matter.Wehavefoundtheconceptmaptobeapowerful teaching/learningtool.Ifyouhavehadnoprevious experiencewiththisdevice,thenitwillbeworthyourwhile toconsult LearningHowtoLearn 1
Whenyouhavedoneallofthisforachapter,then reconsideryourquestions.Discussthemwithotherstudents andcolleagues;consultthe RecommendedReading listat theendofeachchapter;searchPubMed2 forrelevant researchpapersandreview.Withtheexceptionof Chapter2, whichlistspublicationsoflandmarksignificancetothe discoveryofthevitamins,thereadinglistsconsistofkey reviewsinprominentscientificjournals.Thesereviewsand thepaperscitedinthefootnoteswillhelpyou findprimary researchpapersontopicsofspecificinterest.
Last, rereadthechapter.Youwill findthislaststepto beextraordinarilyusefulingainingacommandofthe material,and . Have fun withthisfascinatingand importantaspectofthe fieldofnutrition!
Totheinstructor. Theformatofthistextreflectsthe wayGFCtaught “TheVitamins” coursefornearly27years atCornellUniversity,andJPMsexperiencesasbothstudentandteachingassistant.Someofourexperiencesin using TheVitamins inteachingmaybeofinterest.We believethatyouwill findtheseapproachesusefulwhether youteachinatraditionalorandvirtualclassroom.Infact, thefeaturesidentifi edbeforewillmake TheVitamins particularlyusefulforonlineorself-pacedlearning,asthey willfacilitatealogicalprogressionontopicaldiscussions basedonguidedreadings.Herearegeneralprincipleswe havefoundusefulinteachingandlearningwith The Vitamins:
l BuildonExistingKnowledge.Every studentcomesto thestudyofthevitaminswith some backgroundknowledgeofthesubject,althoughthosebackgroundsare generallyincompleteandfrequentlyincludesome misinformation.Thisistrueforupper-levelnutrition majorsandforstudentsfromother fi elds,thedifference beinglargelyoneofmagnitude.Thisisalsotruefor instructors,mostofwhomcometothe fieldwithspecificexpertisethatrelatestoonlyasubsetofthesubject matter.Youcandemonstratethiswiththefollowing
1.Novak,J.D.,Gowin,D.B.,1984. LearningHowtoLearn.Cambridge, UniversityPress,NewYork,NY,199pp.
2.AfreesearchenginemaintainedbytheUSNationalLibraryof Medicineaccessing w32millionbiomedicalcitationsprimarilythe MEDLINEdatabase.
exercise,bestdoneofthe firstdayofclass.Raise yourindex finger(abitofdramatic flairisalways good)andsay “vitaminA.” Holdthatposefor10 secondsandthenask “WhatcametomindwhenI said ‘vitaminA’?” Withoutfail,mostinagroup willhesitate;butthen,someonewillsay “vision” or “carrots,” andthenamoreseniorgraduatestudent mayadd “toxic” or “beta-carotene.” Whenitlooks safetochimein,otherswilladdwhatwillbuildtoan arrayofdescriptorsthat,collectively,aremorerelevant tovitaminAthananyisindividually.Mostofthe answers,byfar,willrelatetotheclinicalsymptomsof vitaminAdeficiencyandthesourcesofvitaminAin diets.Catcheachanswerbydashingitontoalarge stickynote,andthenpostthenotehaphazardlytoa blackboardorwall.Ifyouhearsomethingcomplexor aclusterofconcepts,questionthecontributoruntil youhearoneormoreindividualconceptswhichyou canrecordonindividualstickynotes.Thisapproach neverfails tostimulatefurtheranswers,anditis commonthatagroupof15 20studentswillgenerate alistoftwicethatnumberofconceptsbeforethe momentumfades.Havingusedstickynotes,itiseasy tomovethemintoclustersand,thus,tousetheactivity toconstructa conceptmap of “vitaminA” basedsolely ontheknowledgethatthestudents,collectively, broughtintotheroom.Thisexercisecandemonstrate anempoweringidea:that,havingatleast some backgroundonthesubjectandbeingmotivated(byanyof anumberofreasons)tolearnmore, every learnerbrings tothestudyofthevitaminsauniqueperspectivewhich maynotbereadilyapparent.
l CreateaLearningCommunity. Meaningfullearning isservedwhenbothinstructorandstudentscometo understandoneanother’sperspectives.Thishastwo benefitsinteachingthevitamins.First,itisinthe instructor’sinteresttoknowthestudents’ ideasand levelsofunderstandingconcerningissuesofvitamin need,function,etc.,suchthatthesecanbebuiltupon andmodi fiedasmaybeappropriate.Second,many upper-levelstudentshaveinterestingexperiences (throughpersonalorfamilyhistories,theirown research,informationfromothercourses,etc.)that canbevaluablecontributionstoclassroomdiscussions. Theseexperiencesareassetsthatcanreducethetemptationtofallbackonthe “instructorknowsall” notion, whichweallknowtobefalse.Toidentifystudent perspectives,itisusefultoassignonthe firstclassfor submissionatthesecondclassawrittenautobiographicalsketch.Distributeyourownasamodel,andask eachstudenttowrite “asmuchoraslittle” asheor shecaresto,recognizingthatyouwilldistributetothe entireclasscopiesofallsubmissions.Thebiographical sketcheswillrangefromafewsentencesthatreveal
littleofapersonalnature,tolongeronesthatprovide manygoodinsightsabouttheirauthors; everyone will helpyoutogettoknowyourstudentspersonallyand togetabetterideaoftheirunderstandingsofthevitaminsandtheirexpectationsofthecourse.Theexercise servesthestudentsinasimilarmanner,promotinga groupdynamicthatfacilitatesclassroomdiscussions.
l Using TheVitamins. TheVitamins canbeusedasa typicaltextfromwhichyoucanmakeregularreading assignmentsaspreparationforeachclass.Thiswill freeyouoftheneedtolectureand,instead,usean opendiscussionformat.Infact,thisapproachallows moreinformationtobecovered,asevenabrilliant lecturersimplycannotcoverthevitaminsinanyreal depthwithinthelimitsoftraditionalclassperiodsand termlengths.Thiswastheoriginalmotivationfor writingthistext,whichallowsshiftingresponsibility forlearningtothelearner.Thisalsoallowsclasstime tobeusedtofacilitatelearningthroughdiscussionsof issuesofstudentinterestorconcern.Often,thismeans clarifyingpointswerenotclearuponreading,and pursuingquestionsstimulatingbythereadingbutnot satisfactorilyaddressedinthetext.Usually,these questionsarenicelyhandledbyelicitingtheviews andunderstandingsofotherstudentsandbythe instructorprovidingsupplementaryinformation.With thisapproach,theinstructor’spreparationinvolves collatingpertinentresearchdatafromthescientifi c literaturethatcansupplementthetext,developing topic-relatedquestionsthatcanstimulatestudentdiscussions.Indevelopingthosequestions,itmaybeusefulto prepareyourownconceptmapsofthesubjectmatter andtofocusquestionsonthelinkagesbetweenconcepts,e.g.: “Howdoesthemodeofentericabsorption ofthetocopherolsrelatetowhatweknowaboutits physiochemicalproperties?” Ifyouareunfamiliar withconceptmapping,thenconsult “LearningHowto Learn”1 andexperimentwiththetechniquetodeterminewhether/howitcanassistyou.TheChapterQuiz questionsand/orCaseStudiescanbeusedasweekly writtenassignmentstokeepstudentsfocusedonthe topicandpreventthemfromlettingthecourseslide
untilexamtime.Moreimportantly,thereislearning associatedwiththethoughtthatnecessarilygoesinto suchwrittenassignments.Tosupportthatlearning, makeapointofgoingovereachassignmentbrie flyat thebeginningoftheclassatwhichitisdue,andreturn itbythe next classwith your writtencomments.You will findthatthe CaseStudies areabstractedfromactual clinicalreports;studentsenjoyanddowellonthese assignments.
l CourseManagement. Themodelusedinteaching The Vitamins atCornellwastoevaluatestudentperformance onthebasisofclassparticipation,weeklywrittenassignments,areviewofarecentresearchpaper,andeitherone ortwowrittenexaminations.Toalloweachstudentto pursueatopicofspecificindividualinterest,students wereaskedtoreviewaresearchpaperpublishedwithin thelastyear,usingthestyleof NutritionReviews. Studentswereaskedtomakeashort(10min)oral, in-classpresentationoftheirreview.Theirreviews wereevaluatedonthebasisofcriticalanalysisandon theimportanceofthepapertothe field.Thisassignment waswellreceived.Becausemanystudentsareinexperiencedinresearchandwill,thus,feeluncomfortable incriticizingit,itishelpfultoconductinadvancea discussionofthegeneralprinciplesofexperimental designandstatisticalinference.Examswerealso concept-oriented:studentsweregivenbriefcasedescriptionsandactualexperimentaldata,andwereaskedtolay outdiagnosticstrategies,develophypotheses,design meansofhypothesistestingandinterpretationofresults, etc.Manystudentsmaypreferthemorefamiliarshortanswertest,whichhaslesslearningvalue;suchinertia canbeovercomebyusingexamplesinclassdiscussions and/orhomeworkassignments.
Wefound TheVitamins tobeofgreatvalueasa readydeskreferenceandasaguideinteachingofthe subjectatCornell.Itisourwishthatitwillassistyou similarlyinyourwork.Pleaseletusknowhowitmeets yourneeds,andhowwemightenhanceitforthatpurpose.
GeraldF.Combs,Jr. JamesP.McClung
PartI Perspectivesonthevitamins innutrition Thispageintentionallyleftblank
Chapter1 Whatisavitamin? Imaginationismoreimportantthanknowledge
ChapterOutline
Anchoringconcepts3
Learningobjectives3
Vocabulary3
1.Thinkingaboutvitamins3
Anchoringconcepts 1. Certainfactors,called nutrients,arenecessaryfor normalphysiologicalfunctionofanimals,including humans.Somenutrientscannotbesynthesized adequatelybythehostandmustthereforebeobtained fromtheexternalchemicalenvironment;theseare referredtoas dietaryessentialnutrients.
2. Diseases involvingphysiologicaldysfunction,often accompaniedbymorphologicalchanges,canresult frominsufficientintakesofdietaryessentialnutrients.
Learningobjectives 1. Tounderstandtheclassicmeaningoftheterm vitamin asitisusedinthe fieldofnutrition.
2. Tounderstandthattheterm vitamin describesbotha conceptoffundamentalimportanceinnutritionand anymemberofaratherheterogeneousarrayofnutrients,anyoneofwhichmaynotfullysatisfytheclassic definition.
3. Tounderstandthatsomecompoundsarevitaminsfor onespeciesandnotanother,andthatsomearevitamins onlyunderspeci ficdietaryorenvironmentalconditions.
4. Tounderstandtheconcepts vitamer and provitamin.
Vocabulary Nutriome
A.Einstein.
2.Vitamin:arevolutionaryconcept4
3.Anoperatingdefinition4
4.Therecognizedvitamins5
5.Chapterquiz6
1.Thinkingaboutvitamins Amongthenutrientsrequiredforthemanyphysiologic functionsessentialtolifearethevitamins.Unlikeother nutrients,thevitaminsdonotservestructuralfunctions,nor doestheircatabolismprovidesigni ficantenergy.Instead, thephysiologicfunctionsofvitaminsarehighlyspeci fic, and,forthatreason,theyarerequiredinonlysmall amountsinthediet.Thecommonfoodformsofmostvitaminsrequiresomemetabolicactivationtotheirfunctional forms.
Althoughthevitaminssharethesegeneralcharacteristics,theyshowfewclosechemicalorfunctionalsimilarities;theircategorizationasvitaminsisstrictlyempirical. Consideralsothat,whereasseveralvitaminsfunctionas enzymecofactors(vitaminsA,K,andC,thiamin,1 niacin, ribo flavin,vitaminB6,biotin,pantothenicacid,folate,and vitaminB12),notallenzymecofactorsarevitamins.2 Some vitaminsfunctionasbiologicalantioxidants(vitaminsE andC),andseveralfunctionascofactorsinmetabolic oxidation reductionreactions(vitaminsE,K,andC, niacin,ribofl avin,andpantothenicacid).Twovitamins (vitaminsAandD)functionashormones;oneofthem (vitaminA)alsoservesasaphotoreceptivecofactorin vision.
1.Thenameofthisvitaminissometimesspelledwithaterminal “e,” i.e., “thiamine.”
2.Otherenzymecofactorsarebiosynthesized,e.g.,heme,coenzymeQ, andlipoicacid.
