TY - JOUR
T1 - The Nitrogen Isotope Ratio Is a Biomarker of Yup'ik Traditional Food Intake and Reflects Dietary Seasonality in Segmental Hair Analyses
AU - Choy, Kyungcheol
AU - Nash, Sarah H.
AU - Hill, Courtney
AU - Bersamin, Andrea
AU - Hopkins, Scarlett E.
AU - Boyer, Bert B.
AU - O'Brien, Diane M.
N1 - Funding Information:
Supported by the National Center for Research Resources and the National Institute of General Medical Sciences of the NIH through grant nos. P20RR016430 and P30GM103325. Author disclosures: KC, SHN, CH, AB, SEH, BBB, and DMO, no conflicts of interest. The contents of this article are solely the responsibility of the authors and do not necessarily represent the official views of the National Center for Research Resources or the NIH. Supplemental Tables 1 and 2 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/. Address correspondence to DMO (e-mail: dmobrien@alaska.edu). Abbreviations used: C/N ratio, carbon to nitrogen ratio; NDSR, Nutrition Data System for Research; NIR, nitrogen isotope ratio.
Publisher Copyright:
Copyright © American Society for Nutrition 2019.
PY - 2019/11/1
Y1 - 2019/11/1
N2 - Background: The nitrogen isotope ratio (NIR) is a promising index of traditional food intake for an Alaska Native (Yup'ik) population, which can be measured in blood and hair. However, the NIR has not been calibrated to high-quality measures of Yup'ik traditional food intake. Objectives: Our primary objective was to examine associations between intakes of Yup'ik traditional food groups, including fish, marine mammals, birds, land mammals, berries, greens, and total traditional foods, and the NIR. In an exploratory analysis, we also examined whether NIR analyzed sequentially along hair could reflect dietary seasonality. Methods: We recruited 68 participants from 2 Yup'ik communities in the Yukon Kuskokwim region of Southwest Alaska (49% female, aged 14-79 y). Participants completed 4 unscheduled 24-h food recalls over the period peak of RBC and hair synthesis preceding a specimen collection visit. The NIR was measured in RBCs (n = 68), a proximal hair section (n = 58), and sequential segments of hair from individuals in the upper 2 quartiles of traditional food intake having hair >6 cm in length, plus 2 low subsistence participants for reference (n = 18). Diet-biomarker associations were assessed using Pearson's correlation and linear regression. Results: Intakes of fish, marine mammals, berries, and greens were significantly associated with the NIR. The strongest dietary association was with total traditional food intake (R2 = 0.62), which indicated that each 1‰ increase in the RBC NIR corresponded to 8% of energy from traditional foods. Hair NIR appeared to fluctuate seasonally in some individuals, peaking in the summertime. Conclusions: Findings support the use of the RBC and hair NIR to assess total traditional food intake in a Yup'ik population. Analyses of sequential hair NIR provided evidence of seasonality in traditional food intake, although seasonal variations were modest relative to interindividual variation.
AB - Background: The nitrogen isotope ratio (NIR) is a promising index of traditional food intake for an Alaska Native (Yup'ik) population, which can be measured in blood and hair. However, the NIR has not been calibrated to high-quality measures of Yup'ik traditional food intake. Objectives: Our primary objective was to examine associations between intakes of Yup'ik traditional food groups, including fish, marine mammals, birds, land mammals, berries, greens, and total traditional foods, and the NIR. In an exploratory analysis, we also examined whether NIR analyzed sequentially along hair could reflect dietary seasonality. Methods: We recruited 68 participants from 2 Yup'ik communities in the Yukon Kuskokwim region of Southwest Alaska (49% female, aged 14-79 y). Participants completed 4 unscheduled 24-h food recalls over the period peak of RBC and hair synthesis preceding a specimen collection visit. The NIR was measured in RBCs (n = 68), a proximal hair section (n = 58), and sequential segments of hair from individuals in the upper 2 quartiles of traditional food intake having hair >6 cm in length, plus 2 low subsistence participants for reference (n = 18). Diet-biomarker associations were assessed using Pearson's correlation and linear regression. Results: Intakes of fish, marine mammals, berries, and greens were significantly associated with the NIR. The strongest dietary association was with total traditional food intake (R2 = 0.62), which indicated that each 1‰ increase in the RBC NIR corresponded to 8% of energy from traditional foods. Hair NIR appeared to fluctuate seasonally in some individuals, peaking in the summertime. Conclusions: Findings support the use of the RBC and hair NIR to assess total traditional food intake in a Yup'ik population. Analyses of sequential hair NIR provided evidence of seasonality in traditional food intake, although seasonal variations were modest relative to interindividual variation.
KW - biomarker evaluation
KW - circumpolar health
KW - dietary seasonality
KW - nitrogen stable isotope ratio
KW - traditional food
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U2 - 10.1093/jn/nxz144
DO - 10.1093/jn/nxz144
M3 - Article
C2 - 31268149
AN - SCOPUS:85074444671
SN - 0022-3166
VL - 149
SP - 1960
EP - 1966
JO - Journal of Nutrition
JF - Journal of Nutrition
IS - 11
ER -