Survey of vitamin D and 25-hydroxyvitamin D in traditional native Alaskan meats, fish, and oils

Greater consumption of traditional foods has been associated with improved vitamin D status in Arctic and sub-Arctic populations, including Alaskan Native Americans. However, lack of vitamin D food composition data impairs epidemiological studies on health outcomes, and development of specific dietary recommendations. Vitamin D, including 25(OH)D3 was quantified in samples of native fish, fish eggs, meats (caribou, goose, whale, seal) and traditionally prepared whale and seal oil collected from Alaskan tribes. Vitamin D3, 25(OH)D3, and vitamin D2 were assayed in alkaline-saponified samples by UPLC-MS, after derivatization with 4-phenyl-1,2,4-triazole-3,5-dione, with in-house control materials and/or NIST SRM® 1546a Meat Homogenate included in each analytical batch. All but the land animals and bearded seal meat contained ≥2 μg vitamin D3/100 g, with >10 μg/100 g in steelhead trout; dried sheefish, whitefish, smelt; smoked/dried salmon; fermented sheefish eggs; whale and seal oils. Large between-sample differences in bearded seal oil suggested possible effects of season and/or maturity on vitamin D content. 25(OH)D3 was >0.3 μg/100 g in many foods, notably smoked salmon, beluga whale skin/fat and oil and spotted seal (but not other seal) oil, with the highest levels in dried beluga whale meat, skin/fat, and oil (up to 1.2). Vitamin D2 was <0.2 μg/100 g in all foods.