Reference Materials for the Nutrition Community
The Future of Reference Materials - Science and Innovation
23 November 2010
Joseph M. Betz1, Mary Frances Picciano1, Karen Phinney2
1Office of Dietary Supplements, National Institutes of Health 2National Institute for Standards and Technology
OFFICE OF DIETARY SUPPLEMENTS 2
NIH is the Nation’s Medical Research Agency
www.nih.gov
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Reference Materials and ODS
ODS Analytical Methods and Reference Materials Program- multi-year project with NIST
• “Suites” of Standard Reference Materials – Supplement raw materials & finished products – Certified and Reference values for marker compounds,
nutrients, contaminants
• Calibration Standards www.nist.gov
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Outcomes
Available• Botanicaloils(tocopherols)• Fishoil(FAs,tocopherols)• Ginkgo• Bi:erorange• Sawpalme:o• Mul?vitamin/mineraltablets• Botanical&fishoils(Ω3’s,6’s)• Greentea• Berries• Vit.Dinhumanserum
In Process • St.John’swort• Soy• Blackcohosh• Kudzu• Redclover• Turmeric• Pomegranate• Ginsengs(Asian,Siberian)
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Foodswithvaluesassignedfornutrients(proximates,vitamins,carotenoids,elements,fa:yacids,aminoacidsasappropriate)
• SRM1849Infant/AdultNutri?onalFormula• SRM1946LakeSuperiorFishTissue• SRM2384BakingChocolate• SRM2385SlurriedSpinach• SRM2387PeanutBu:er• SRM3287Blueberry(Fruit)plus5moreinprogress
NIST SRM for Nutrition (available prior to ODS program)
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• 909c‐Glucose,urea,uricacid,cholesterol,crea?nine,totalprotein,electrolytes
• 968e‐Fat‐SolubleVitamins,Carotenoids,Cholesterol,tocopherols,re?nol,beta‐carotene
• 2670‐ToxicElementsinUrine:14elements• 3950‐VitaminB6inHumanSerum
• 3951‐VitaminB12inHumanSerum
NIST SRM for Nutrition
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CaseStudy:
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Vitamin D Status of the US Population?
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Lookeretal.AmJClinNutr2008;88:1519‐27.
• 1988-94 vs. 2000 - 2004: − Reformulation (introduction of antibody to
improve binding) of RIA assay kit shifts in assay results between these two time periods
− Adjusted for assay drifts to compare time trends in 25(OH)D and identify contributing factors
25(OH)D Assay Concerns (Looker et al., 2008)
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• Adjustments for assay differences: − Looker et al. (2008):
• Overall mean 25(OH)D lower in 2000-2004 than in 1988-94 • Assay changes accounted for much of the difference
• No adjustment for assay differences: − Ginde et al. (2009):
• Marked decrease in 25(OH)D in 2000-2004 from 1988-1994 • Growing epidemic of vitamin D insufficiency
− Saintonge (2009): • Vitamin D deficiency is increasing from 1988-1994 to 2006 • National fortification and public health strategy
Adjustment Affects Policy Conclusions
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• SRM972‐VitaminDmetabolitesinHumanSerum− Suiteoffour1.0mlvialswithcer?fiedandreference
valuesfor25(OH)D2,25(OH)D3,and3‐epi‐25(OH)D3
• SRM2972‐25(OH)D2&25(OH)D3Calibra?onSolu?ons− SRM2972isasetofethanoliccalibra?onsolu?onsand
hascer?fiedvaluesfor25(OH)D2and25(OH)D3
• Valueassignmentbyisotope‐dilu?onLC‐MSandLC‐MS/MS
• RMdrivesscience‐previouslythought3‐epionlyoccurredininfants
NIST SRM- July 2009
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• Ques%onsaboutequivalenceofLC/MSassayresponseto25(OH)D2and25(OH)D3
− Immunoassaysmeasure“total”25(OH)D
− OlderLC/MSmethodsdidnotresolve3‐epimer
• 3‐epimersof25(OH)DmaybiasMS‐basedmethods
25(OH)D3 3‐epi‐25(OH)D3
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NIST LC-MS Methodology for 25(OH)D
25(OH)D2‐[2H3]25(OH)D3‐[2H6]
25(OH)D3
3‐epi‐25(OH)D3
25(OH)D2
Taietal.(2010)AnalChem82:1942‐1948
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Level165±15nmol/L25‐hydroxyvitaminD3(“normal”)
Level2Blendof“normal”serumandhorseserumtoobtainapproximatelyhalfthelevelof25‐hydroxyvitaminD3inthe“normal”pool(35±5nmol/L)
Level3“Normal”serumspikedwithequivalentamountof25‐hydroxyvitaminD2
Level4“Normal”serumspikedwith3‐epi‐25‐hydroxyvitaminD3
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CommutabilityisdefinedastheequivalenceofthemathemaZcalrelaZonshipsbetweentheresultsofdifferentmeasurementproceduresforareferencematerialandforrepresentaZvesamplesfromhealthyanddiseasedindividuals.
Vesperetal.,Clin.Biochem.Rev.,28(2007)139
Reasonsareferencematerialmaynotbecommutable:
• Materialhandling,processing(lyophiliza?on,filtering,etc.)
• Supplementa?onwithna?veornon‐na?veanalytes
• Differencesbetweensamplesfromhealthyanddiseasedindividuals
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OtherRMneeds
Marketedproducts‐matrices• Delayedreleasedosageforms‐ionexchangeresins,etc.
• Oil‐filledgelcaps‐vegetarianandanimalgela?n
• Microencapsulatedmaterials‐Carrageenan,gela?n,etc.
• “Nano”ingredientsinfinishedproducts• “Unusual”matrixsourcefornutrientsandnutrientelements‐e.g.iodineinkelpvsKI
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OtherRMneeds
Clinicalmaterialsandcalibra?onstandards• Folate,othercomplexvitamersinserumforLC/MS
• Biomarkersofnutrientexposurevs.markersofNutrientstatus‐e.g.Omega‐3fa:yacidsinserumvs.redbloodcellmembrane
• Isotopelabelednutrientsandmetabolitesascalibra?onstandardsforMSdetec?on
• Serumbasedcalibra?onsolu?ons
Yetleyetal.(2010)JNutr140:2030S‐2045S
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Non-RM Activities
NIST Vitamin D metabolite Laboratory Quality Assurance Program & Dietary Supplement Laboratory Quality Assurance Program
• NIST sends blinded material, practice sample – Participants perform analyses and return data to NIST – NIST provides feedback on blinded results, including
suggestions for method optimization
• To participate (no cost), send e-mail to [email protected]@nist.gov
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“Reference Materials are the most efficient means to transfer accuracy to a field” -John Eckfeldt, MD, Ph.D. Professor of Laboratory Medicine, University
of Minnesota Medical Center
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www.ods.od.nih.gov E-mail: [email protected]
E-mail: [email protected]
Joseph M. Betz
http://dietary-supplements.info.nih.gov/FactSheets/AMRMProgramWebsite.asp