Julia Kühn, Dipl., Alexandra Schutkowski (Dr.), Holger Kluge (Dr.), Frank Hirche (Dr.),
Gabriele I. Stangl (Dr.) gabriele.stangl at landw.uni-halle.de
Institute of Agricultural and Nutritional Sciences, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
Objective: Food-based strategies need to be developed to improve the vitamin D status of individuals. Recent studies identified UVB irradiation as an efficient method to enrich mushrooms and eggs with vitamin D. These findings prompted us to test, whether free-range farming of hens could provide a valuable method to produce vitamin D-enriched eggs.
Methods: Laying hens were randomly assigned to three groups of 33/34 animals each, and were kept either indoors (indoor group), outdoors (outdoor group) or with an indoor/outdoor option (indoor/outdoor group) over 4 weeks.
Results: Here we show that the vitamin D3 content of egg yolk was 3- to 4-fold higher in the groups that were exposed to sunlight (outdoor group and indoor/outdoor group) compared to the indoor group (P<0.001). Egg yolk from the outdoor group revealed the highest vitamin D3 content which averaged 14.3 μg/100 g dry matter (DM), followed by that from the indoor/outdoor group (11.3 μg/100 g DM). Yolk from indoor eggs contained only 3.8 μg vitamin D/100 g DM. The 25(OH)D3 content of egg yolk was also influenced by sunlight exposure, although less pronounced than the vitamin D content (P<0.05). In contrast, free-range eggs randomly acquired from supermarkets had relatively low vitamin D contents.
Conclusion: Free-range farming offers an efficient alternative to fortify eggs with vitamin D, provided that the farming conditions are sufficiently attractive for the hens to range outside.
- 200 IU per 100 gram of egg yoke when add vitamin D to poultry feed in Europe – Aug 2011
- UVB on legs of chickens resulted in 70 IU vitamin D per egg yoke – July 2013
- Hens with Vitamin D were better in at least 5 ways – RCT Aug 2018
- Egg vitamin D levels are not permitted to be restored to levels before chickens were raised indoors – Feb 2017
- Infant higher Vitamin D if mom took sun, took Vit D, was not obese, or ate eggs (China) – Feb 2019
- Vitamin D from animal increases 6X when consider that already processed by animal livers
- Feed chicken lots of vitamin D, get 6000 IU per egg with no change in production – Nov 2013
- Omega-3 from biofortified eggs is practical (and great for health) – Nov 2015
- Add vitamin D to animal feed to fortify the resulting human food – Oct 2012
- Animal feed fortification is rarely permitted anywhere around the world
- Vitamin D Fortification of Eggs for Human Health Journal of the Science of Food and Agriculture, Oct 2013
Depending on the dietary concentrations used, it was possible to produce eggs with between 200–700 iu vitamin D
- How do different eggs stack up in terms of flavor, nutrition and animal welfare? Mercola June 2019
Description with video of differences between free run (indoors) < cage free (indoors) < free range = pasture riaised = organic