By Siena Mantooth
When I was a child, my mom purchased eggs for us to dye around the Easter holiday. She almost always bought white eggs, but I distinctly remember one time when she bought brown eggs. My siblings and I quickly discovered that brown eggs required more time to dye than white eggs, and the resulting colors were not quite the same. Disappointed as we were, from then on, my mom purchased white eggs, which we eagerly awaited every Saturday before Easter.
Chicken eggs come in different colors. The egg shells shown here range from white to blue to brown. Image by Kelly Neil at unsplash.com.
Eggs are not as simple as they may seem. White eggs, brown eggs, blue eggs – why so many colors? The complexity does not stop at the shell, either. Some eggs have pale, barely yellow yolks, while others have deep, rich orange yolks. People associate certain colors with higher nutritional value, such as brown eggs with deep orange yolks as being “healthier,” but they may be mistaken in these assumptions.
The egg shell is primarily composed of calcium carbonate, which appears white. Three primary dyes can make the shell appear a different color: protoporphyrin, biliverdin, and biliverdin-zinc chelate. Brown shells have more protoporphyrin, while green or blue shells have more biliverdin and biliverdin-zinc chelate. These dyes are present in the shell because of the chicken’s genetics; the nutritional value of the eggs does not change based on its shell color.
The egg yolk, too, can come in different colors. The color of egg yolks is determined by carotenoid content, which are naturally occurring pigments often found in vegetables and fruits. Hens cannot make carotenoids and instead eat them. Therefore, the color of the egg yolk depends on the hen’s diet. Typically, wheat-based diets have low amounts of carotenoids, while corn and alfalfa diets have higher amounts and can therefore deepen the yolk color. However, just because an egg has a deeper color does not necessarily mean it is a more natural or healthy option. For example, hens can be fed diets with synthetic or natural additives to change their yolk color, and some synthetic additives can be toxic to human health.
Egg yolks come in different colors. Shown is a dark orange yolk and a bright yellow yolk. Image by Klaus Nielsen on pexels.com.
Besides these variables, are there eggs that have a superior nutritional quality? Research has not definitively made a conclusion. However, some studies have suggested that pasture-raised chickens may afford more vitamin E and vitamin A, lower omega-6 to omega-3 ratio, and higher carotenoid amount compared to conventionally-raised chickens. Either way, eggs are an egg-cellent source of protein, vitamins, and minerals. Adding them to your morning meal or diet may be a very good health choice.
