Do eggs have b12
Pro Research Analysisby 
Searched over 200M research papers
Vitamin B12 Content in Eggs
Presence of Vitamin B12 in Eggs
Eggs do contain vitamin B12, primarily in the yolk. Research has shown that the concentration of vitamin B12 in egg yolk can vary significantly based on the hen's diet. For instance, hens fed diets with higher levels of vitamin B12 produce eggs with higher concentrations of this vitamin. Specifically, egg yolk vitamin B12 concentrations can range between 1.3 and 2.6 micrograms per 100 grams of yolk, which is necessary to support optimal egg production and hatchability 18.
Factors Affecting Vitamin B12 Levels in Eggs
The vitamin B12 content in eggs is influenced by several factors, including the hen's diet and the storage conditions of the eggs. Hens that receive adequate dietary supplementation of vitamin B12 produce eggs with higher vitamin B12 content. For example, a diet containing 8.0 micrograms/kg of vitamin B12 resulted in maximum egg production and optimal egg quality . Additionally, eggs stored for extended periods, such as twelve months, can experience a loss of vitamin B12 content .
Bioavailability of Vitamin B12 from Eggs
The bioavailability of vitamin B12 from eggs can be affected by the presence of binding proteins in the egg yolk and egg white. Studies have shown that egg yolk inhibits vitamin B12 absorption less than egg white, suggesting that different binding proteins are present in these components. Heat treatment also differentially affects the binding capacity of these proteins, with egg white showing a greater decrease in binding capacity upon heating . Furthermore, the form of vitamin B12 in century eggs (pidan) is more readily digestible, with a significant portion of the vitamin B12 being converted to a free form during gastric digestion .
Impact of Vitamin B12 on Egg Quality and Hen Health
Adequate levels of vitamin B12 in the diet of laying hens are crucial for maintaining egg quality and the health of the hens. Higher dietary levels of vitamin B12 have been associated with increased egg weight, improved hatchability, and better overall hen health. Conversely, deficiencies in vitamin B12 can lead to reduced egg production and poor egg quality 168. Additionally, vitamin B12 plays a significant role in various metabolic pathways in hens, including lipid, protein, and nucleic acid metabolism 78.
Conclusion
In summary, eggs are a source of vitamin B12, primarily found in the yolk. The concentration of vitamin B12 in eggs is influenced by the hen's diet and storage conditions. While the bioavailability of vitamin B12 from eggs can be affected by binding proteins and heat treatment, ensuring adequate dietary supplementation of vitamin B12 for hens is essential for optimal egg production and quality.
Sources and full results
Most relevant research papers on this topic