title: A Dual-Carbon-and-Nitrogen Stable Isotope Ratio Model Is Not Superior to a Single-Carbon Stable Isotope Ratio Model for Predicting Added Sugar Intake in Southwest Virginian Adults.
abstract: BACKGROUND
  An objective measure of added sugar (AS) and sugar-sweetened beverage (SSB) intake is needed. The δ(13)C value of finger-stick blood is a novel validated biomarker of AS/SSB intake; however, nonsweetener corn products and animal protein also carry a δ(13)C value similar to AS sources, which may affect blood δ(13)C values. The δ(15)N value of blood has been proposed as a "correction factor" for animal protein intake.
  
  
  OBJECTIVE
  The objectives were to 1) identify foods associated with δ(13)C and δ(15)N blood values, 2) determine the contribution of nonsweetener corn to the diet relative to AS intake, and 3) determine if the dual-isotope model (δ(13)C and δ(15)N) is a better predictor of AS/SSB intake than δ(13)C alone.
  
  
  METHODS
  A cross-sectional sample of southwest Virginian adults (n = 257; aged 42 ± 15 y; 74% overweight/obese) underwent dietary intake assessments and provided finger-stick blood samples, which were analyzed for δ(13)C and δ(15)N values by using natural abundance stable isotope mass spectrometry. Statistical analyses included ANOVAs, paired-samples t tests, and multiple linear regressions.
  
  
  RESULTS
  The mean ± SD daily AS intake was 88 ± 59 g and nonsweetener corn intake was 13 ± 13 g. The mean δ(13)C value was -19.1 ± 0.9‰, which was significantly correlated with AS and SSB intakes (r = 0.32 and 0.39, respectively; P ≤ 0.01). The δ(13)C value and nonsweetener corn intake and the δ(15)N value and animal protein intake were not correlated. AS intake was significantly greater than nonsweetener corn intake (mean difference = 76.2 ± 57.2 g; P ≤ 0.001). The δ(13)C value was predictive of AS/SSB intake (β range: 0.28-0.35; P ≤ 0.01); however, δ(15)N was not predictive and minimal increases in R(2) values were observed when the δ(15)N value was added to the model.
  
  
  CONCLUSIONS
  The data do not provide evidence that the dual-isotope method is superior for predicting AS/SSB intakes within a southwest Virginian population. Our results support the potential of the δ(13)C value of finger-stick blood to serve as an objective measure of AS/SSB intake. This trial was registered at clinicaltrials.gov as NCT02193009.
authors: Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA; and vhedrick@vt.edu.
authors: Valisa E
authors: VE
authors: Hedrick
authors: Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA; and.
authors: Jamie M
authors: JM
authors: Zoellner
authors: School of Earth and Ocean Science and Technology, University of Hawaii at Manoa, Honolulu, HI.
authors: A Hope
authors: AH
authors: Jahren
authors: Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA; and.
authors: Natalie A
authors: NA
authors: Woodford
authors: School of Earth and Ocean Science and Technology, University of Hawaii at Manoa, Honolulu, HI.
authors: Joshua N
authors: JN
authors: Bostic
authors: Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA; and.
authors: Brenda M
authors: BM
authors: Davy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001628:Beverages; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D002241:Carbohydrates / Q000008:administration & dosage*; D002247:Carbon Isotopes / Q000097:blood*; D003430:Cross-Sectional Studies; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage; D002149:Energy Intake; D005247:Feeding Behavior; D006801:Humans; D008875:Middle Aged; D008962:Models, Theoretical; D009587:Nitrogen Isotopes / Q000097:blood*; D015596:Nutrition Assessment; D009765:Obesity / Q000097:blood; D050177:Overweight / Q000097:blood; D013549:Sweetening Agents / Q000008:administration & dosage*; D014768:Virginia; D055815:Young Adult
chemical_list: D015415:Biomarkers; D002241:Carbohydrates; D002247:Carbon Isotopes; D004044:Dietary Proteins; D009587:Nitrogen Isotopes; D013549:Sweetening Agents
keywords: added sugars; biomarker validation; dietary assessment; obesity; sugar-sweetened beverages