Locally harvested foods support serum 25-hydroxyvitamin D sufficiency in an indigenous population of Western Alaska

Abstract

Background

Low serum vitamin D is associated with higher latitude, age, body fat percentage and low intake of fatty fish. Little documentation of vitamin D concentrations is available for Alaska Native populations.

Objective

This study was undertaken to investigate serum 25-hydroxyvitamin D (25(OH)D) concentrations of the Yup'ik people of southwestern Alaska in relation to demographic and lifestyle variables, particularly with the use of locally harvested (local) foods.

Design

Cross-sectional study.

Methods

We estimated 25(OH)D, dietary vitamin D and calcium, percent of energy from local foods and demographic variables in 497 Yup'ik people (43% males) aged 14–92 residing in southwestern Alaska. Sampling was approximately equally divided between synthesizing and non-synthesizing seasons, although the preponderance of samples were drawn during months of increasing daylight.

Results

Mean vitamin D intake was 15.1±20.2 µg/d, while local foods accounted for 22.9±17.1% of energy intake. The leading sources of vitamin D were local fish (90.1%) followed by market foods. Mean 25(OH)D concentration was 95.6±40.7 nmol/L. Participants in the upper 50th percentile of 25(OH)D concentration tended to be older, male, of lower body mass index, sampled during the synthesizing season, and among the upper 50th percentile of local food use.

Conclusions

A shift away from locally harvested foods will likely increase the risk for serum 25(OH)D insufficiency in this population.

• Vitamin D
• 25-hydroxyvitamin D
• Alaska Natives
• Traditional Foods
• Seasonality
• Dietary transition

Acknowledgements

We are grateful for the assistance of Scarlett Hopkins to our research field team. We thank Irena King, then at the Fred Hutchinson Cancer Research Center, for the fatty acid analyses.