When I started looking into raising hens for the eggs, I learned that a lot of people add crushed eggshells to their hens’ food. They do this because the calcium and other minerals in the eggshells are bio-available to chickens, and it eliminates the need for a calcium supplement. When laying hens don’t get enough calcium they lay eggs with very soft shells. Ever since I learned about this, I’ve wondered about the bio-availability of calcium in eggshells for humans. I thought about sending a couple eggshells out to a lab to be tested, but I really don’t have the resources or knowledge to do so. I know a biochemist, and thought about asking her to test eggshells for me, but she really shouldn’t use her employer’s lab equipment to fulfill my curiosity, so I never asked her.
It seems that I’m not the only person to follow this line of thinking. This article on Natural News explains exactly how to make your own mineral supplement from eggshells, and tells you what minerals you’re getting and in what quantities.