Is there calcium in eggs
Pro Research Analysisby 
Searched over 200M research papers
Consensus Meter
Calcium Content in Eggs: An Overview
Calcium in Eggshells
Eggshells are predominantly composed of calcium carbonate, making up about 95% of the dry eggshell weight. This translates to approximately 5.5 grams of calcium carbonate per eggshell, which includes traces of other minerals such as sodium, potassium, zinc, manganese, iron, and copper . The high calcium content in eggshells makes them a potential source for calcium supplements, which can be extracted using various techniques like electric discharge-assisted mechanical milling and high-energy milling.
Calcium in Egg Yolk and Egg White
While the primary function of calcium in eggs is to form the eggshell, small quantities of calcium are also present in the egg yolk and egg white. These minor amounts are integral to the overall nutritional profile of the egg. The presence of calcium in these parts of the egg, although not as significant as in the shell, contributes to the dietary intake of calcium when eggs are consumed.
Impact of Dietary Calcium on Egg Composition
The calcium content in eggs can be influenced by the dietary calcium levels provided to laying hens. Studies have shown that increasing the calcium levels in the diet of hens can significantly affect the mineral content of both the eggs and the eggshells. For instance, hens fed with higher calcium levels (up to 5.5%) produced eggs with significantly higher calcium content in the eggshells compared to those fed with lower calcium levels. This indicates that dietary calcium directly impacts the calcium deposition in eggs.
Calcium Requirements for Laying Hens
Laying hens require a substantial amount of calcium for optimal egg production and eggshell quality. It is estimated that for every egg laid, about 1.8 to 2.0 grams of calcium is mobilized and ejected from the hen's body. To meet this demand, hens are typically provided with diets containing around 2.25% calcium, which equates to approximately 2.0 to 2.5 grams of calcium per day. Adequate calcium intake is crucial not only for eggshell formation but also for maintaining the overall health and bone strength of the hens .
Health Benefits and Applications
The high calcium content in eggshells has led to their consideration as a cheap and effective alternative to traditional calcium supplements. Eggshell calcium can be used for food fortification, providing a sustainable way to reduce eggshell waste while enhancing dietary calcium intake. Additionally, the bioavailability of calcium from eggshells can be improved through various processing techniques, making it a viable option for calcium supplementation.
Conclusion
In summary, eggs contain calcium primarily in their shells, with smaller amounts present in the yolk and white. The calcium content in eggs can be influenced by the dietary intake of laying hens, highlighting the importance of adequate calcium provision for optimal egg production and quality. Eggshells, rich in calcium carbonate, offer a promising source for calcium supplements, contributing to both nutritional and environmental benefits.
Sources and full results
Most relevant research papers on this topic