An exploratory study of the content of vitamin D compounds in selected samples of Australian eggs

Abstract

Aim The aim of this study was to obtain preliminary indicative data for vitamin D3 (cholecalciferol) and 25‐hydroxycholecalciferol (25OHD3) in Australian chicken egg yolk (Gallus gallus domesticus, Linnaeus, 1758), comparing data with the egg yolk of other species, crocodile (Crocodylus porosus, Schneider, 1801) and salmon (Salmo salar, Linnaeus, 1758). Methods Convenience samples of chicken eggs were obtained from a producer known to fortify feed with 25OHD3 as well as D3 (Brand A; n = 6), a producer with an unknown feeding protocol (Brand B; n = 6) and a producer known to use low levels of only feed vitamin D3 (University of Sydney; n = 4). Salmon roe (50 g jar) was obtained from a retail outlet and crocodile eggs (n = 2) from a commercial crocodile farm. Egg yolks and whole salmon roe were analysed for vitamin D3 and 25OHD3 by high‐performance liquid chromatography. Results Brand A and B chicken egg yolks contained 2.9 and 2.1 μg vitamin D3/100 g, respectively, while University of Sydney eggs contained lower concentrations (0.5 μg/100 g). Further, yolk from brand A and B chicken eggs contained 4.2 and 1.4 μg 25OHD3/100 g, respectively. Salmon roe contained 6.3 μg vitamin D3/100 g and vitamin D3 content of two crocodile egg yolks differed widely (10.9 and 0.7 μg/100 g). Conclusions The vitamin D in chicken eggs has the potential to contribute considerably to the vitamin D content of the Australian diet, up to 3.8 μg vitamin D equivalents per egg, depending on the form of feed vitamin D. Further representative samples of all edible or potentially edible Australian egg species require analysis for public health nutrition purposes.

Vitamin D3 and 25-Hydroxyvitamin D3 Content of Retail White Fish and Eggs in Australia

“…Authors suggested that sunlight exposure was a likely influence. A previous study in Australia found that egg yolk contained 38% more vitamin D 3 and 300% more 25(OH)D 3 when hen feed was fortified with both vitamin D 3 and 25OH)D 3 [ 8 ]. Feed fortification with only vitamin D 3 also increases the content of both vitamin D 3 and 25(OH)D 3 in eggs [ 33 ].…”

“…Both white fish and eggs available in Australia may provide nutritionally useful amounts of vitamin D; however, conveying this information to consumers is hampered by the lack of Australian food composition data. In addition, 25(OH)D 3 is not recognised in the Australia New Zealand Food Standards Code as contributing to the vitamin D content of foods [ 38 ], despite 25(OH)D 3 being used as a fortificant in animal feed, including in layer poultry farming [ 8 ]. The Food Standards Code states that one serve of a food must contain at least 1 µg of vitamin D for a general “source of” claim, or 2.5 µg of vitamin D for a “good source of” claim [ 38 ].…”

“…In Australia, dietary correction of vitamin D deficiency is complicated by lack of locally relevant vitamin D food composition data [ 7 ]. Since variations in nutritional content of produce may occur with geographical location, climate, feed fortification and animal production practices [ 8 ], it is inappropriate to rely on international vitamin D composition data. Furthermore, international data may not represent species and types of foods commonly consumed in Australia [ 9 ].…”

“…Furthermore, international data may not represent species and types of foods commonly consumed in Australia [ 9 ]. Since 2013, vitamin D 3 and 25(OH)D 3 have been measured in a limited number of Australian meat [ 10 ], egg [ 8 ] and seafood [ 11 ] samples, based on convenience or purposive sampling. We build on these studies by presenting new data for the vitamin D 3 and 25(OH)D 3 content of white fish and eggs purchased from retail outlets across five cities in Australia.…”

Vitamin D Content of Australian Native Food Plants and Australian-Grown Edible Seaweed

“…However, although D 3 is found in several plants, previous results have come mostly from non-edible leaves rather than the edible portions of the different species, such as fruits or seeds. The hydroxylated metabolite of vitamin D 3 , 25(OH)D 3 , is found in animal products [ 8 , 9 , 10 ] and likely has a greater biological activity than vitamin D 3 itself [ 11 , 12 ]. There is some evidence that vitamin D 3 taken orally is more effective than vitamin D 2 at increasing levels of 25(OH)D [ 13 , 14 ].…”