TY - JOUR
T1 - Inclusion of Vitamin A intake data provides improved compartmental model-derived estimates of vitamin a total body stores and disposal rate in older adults
AU - Green, Michael H.
AU - Ford, Jennifer Lynn
AU - Green, Joanne Balmer
N1 - Funding Information:
Support for this work was provided by the Bill & Melinda Gates Foundation (Project Number OPP1115464) and the College of Health and Human Development, The Pennsylvania State University. Supplemental Tables 1–3, Supplemental WinSAAM Deck, and Supplemental References are available from the “Supplementary data” link in the online posting of the article and from the same link in the online table of contents at https://academic.oup.com/jn/. MHG and JLF contributed equally to this work. Address correspondence to MHG (e-mail: [email protected]). Author disclosures: MHG, JLF, and JBG, no conflicts of interest. Abbreviations used: DI, dietary intake; DR, disposal rate; EV, extravascular; FDp, fraction of administered dose in plasma; TBS, total body stores.
Publisher Copyright:
© 2019 American Society for Nutrition. All rights reserved.
PY - 2019/7/1
Y1 - 2019/7/1
N2 - Background: Sampling times and study duration impact estimates of kinetic parameters and variables including total body stores (TBS) and disposal rate (DR) when compartmental analysis is used to analyze vitamin A kinetic data. Objective: We hypothesized that inclusion of dietary intake (DI) of vitamin A as an additional input would improve confidence in predictions of TBS and DR when modeling results appear to indicate that studies are not long enough to accurately define the terminal slope of the plasma retinol isotope response curve. Methods: We reanalyzed previously published data on vitamin A kinetics monitored over 52 d in 7 US and 6 Chinese adults (means: 56 y, BMI 26.6 kg/m2, 38% males), adding an estimate for vitamin A intake [2.8 μmol/d (mean RDA)] as an input during application of the Simulation, Analysis and Modeling software. Results: Use of a model with 1 extravascular compartment (1 EV), as in the original analysis, resulted in predictions of vitamin A intake that were higher than physiologically reasonable; inclusion of intake data in a model with 2 extravascular compartments (2 EV DI) resulted in more realistic estimates of intake and DR. Specifically, predictions of DR by the 2 EV DI (versus 1 EV) model were 2.10 compared with 12.2 μmol/d (US) and 2.21 compared with 5.13 μmol/d (Chinese). Predictions of both TBS [2056 compared with 783 μmol (US) and 594 compared with 219 μmol (Chinese)] and days of vitamin A stores [981 compared with 64 d (US) and 269 compared with 43 d (Chinese)] were higher using the new approach. Conclusions: Inclusion of vitamin A intake as additional data input when modeling vitamin A kinetics can compensate for less-than-optimal study duration, providing more realistic predictions of vitamin A TBS and DR. This approach advances the application of compartmental analysis to the study of vitamin A and, potentially, other nutrients.
AB - Background: Sampling times and study duration impact estimates of kinetic parameters and variables including total body stores (TBS) and disposal rate (DR) when compartmental analysis is used to analyze vitamin A kinetic data. Objective: We hypothesized that inclusion of dietary intake (DI) of vitamin A as an additional input would improve confidence in predictions of TBS and DR when modeling results appear to indicate that studies are not long enough to accurately define the terminal slope of the plasma retinol isotope response curve. Methods: We reanalyzed previously published data on vitamin A kinetics monitored over 52 d in 7 US and 6 Chinese adults (means: 56 y, BMI 26.6 kg/m2, 38% males), adding an estimate for vitamin A intake [2.8 μmol/d (mean RDA)] as an input during application of the Simulation, Analysis and Modeling software. Results: Use of a model with 1 extravascular compartment (1 EV), as in the original analysis, resulted in predictions of vitamin A intake that were higher than physiologically reasonable; inclusion of intake data in a model with 2 extravascular compartments (2 EV DI) resulted in more realistic estimates of intake and DR. Specifically, predictions of DR by the 2 EV DI (versus 1 EV) model were 2.10 compared with 12.2 μmol/d (US) and 2.21 compared with 5.13 μmol/d (Chinese). Predictions of both TBS [2056 compared with 783 μmol (US) and 594 compared with 219 μmol (Chinese)] and days of vitamin A stores [981 compared with 64 d (US) and 269 compared with 43 d (Chinese)] were higher using the new approach. Conclusions: Inclusion of vitamin A intake as additional data input when modeling vitamin A kinetics can compensate for less-than-optimal study duration, providing more realistic predictions of vitamin A TBS and DR. This approach advances the application of compartmental analysis to the study of vitamin A and, potentially, other nutrients.
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U2 - 10.1093/jn/nxz056
DO - 10.1093/jn/nxz056
M3 - Article
C2 - 31095324
AN - SCOPUS:85069264507
SN - 0022-3166
VL - 149
SP - 1282
EP - 1287
JO - Journal of Nutrition
JF - Journal of Nutrition
IS - 7
ER -