An egg a day produced this way could provide recommended daily amount of vitamin D
Washington, D.C. -- The vitamin D3 content of eggs can be raised sevenfold by tripling the vitamin D in chicken feed, according to a study by Finnish scientists published in the Oct. 18 issue of the Journal of Agricultural and Food Chemistry, a peer-reviewed publication of the American Chemical Society, the world's largest scientific society.
"We found that the daily eating of one egg produced this way will provide the daily recommended amount of vitamin D. Given the importance of vitamin D to human health and the difficulties some people have in getting it into their diets, the possibility of producing vitamin D-enriched eggs is worthy of consideration," said Pirjo Mattila, Ph.D., senior researcher at the Agricultural Research Centre of Finland and the study's principal investigator.
Vitamin D is crucial for normal bone formation and may help prevent postmenopausal osteoporosis. People synthesize vitamin D in their skin with the help of sunlight, but inhabitants of northern countries, where sunlight can be scarce during much of the year, need to eat foods rich in vitamin D or take supplements. Foods rich in vitamin D include fish, some wild mushrooms, and egg yolks. Milk, liver, and some meats contain lower levels of vitamin D. Eggs are interesting to consider as a vitamin D source because in addition to vitamin D3, they contain significant levels of the more active hydroxylated metabolite, 25-hydroxy-vitamin D3.
"We believe our study is the first to systematically follow vitamin D concentrations and metabolism in eggs as these factors are affected by feed with different vitamin D levels," said Mattila.
The work was done on 54 hens over six weeks, 90 percent of them in laying mode at the study's beginning and all them 30 weeks old. They were divided into three groups, with each group receiving different levels of vitamin D3 in their feed. All of the hens ate a standard feed mixture containing 2,496 IU of vitamin D3 per kilogram for a one-week balancing period prior to the study's commencement.
Hens that ate feed containing less vitamin D than present in the balancing period feed amounts produced eggs with decreased vitamin D levels (as compared to common store-bought eggs) in the yolks. Hens that ate feed containing the same amount of vitamin D as was present in the balancing period feed produced eggs that contained the same amount of vitamin D as found in store-bought eggs. The hens that consumed feed containing 3.5 times the vitamin D as found in the balancing period feed produced eggs that contained seven times the vitamin D3 and 1.5 times the vitamin D3 metabolite found in store-bought eggs.
Mattila's study colleagues were Professors Vieno Piironen and Kaisa Lehikoinen of the University of Helsinki's applied chemistry and microbiology department and Professor Tuomo Kiiskinen of the Agricultural Research Centre of Finland.
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