The color of an eggshell has pervasively influenced the way people perceive what is inside. For decades, impressions of brown eggs compared to white eggs have had people going one way or the other as far as purchasing them. But do brown eggs have more nutritional benefits compared to their white-shelled brethren?
Brown Eggs vs. White Eggs: a Matter of Genetics
The color of eggshells actually depends on the breed of the chicken that produced them.
For example, White Leghorn chickens lay white-shelled eggs, while Plymouth Rocks and Rhode Island Reds lay brown-shelled eggs. Some breeds of chicken, such as the Araucana, Ameraucana, Dongxiang, and Lushi, even lay blue or blue-green eggs.
The different eggshell colors come from pigments the hens produce. The main pigment in brown eggshells is called protoporphyrin IX. This pigment is made from heme, the same compound that gives blood its red color.
Eggshells may also vary in color among the same breed of chickens, depending on genetic dominance among individual birds.
Other Factors That Influence Why Eggs Are Brown
But while genetics is the main factor that determines egg color, other factors can also influence it.
Among these factors are a hen’s environment, diet, and even the level of stress they are under. As hens that lay brown eggs age, they sometimes tend to lay larger and lighter-colored eggs.
The hen’s environment can have a major effect as eggs from hens that are allowed to roam in the sunshine contain 3-4 times the amount of vitamin D you’d find in eggs from conventionally raised hens. The type of feed a hen eats can also affect the nutrient content of her eggs.
Hens fed a diet rich in omega-3 fatty acids produce eggs that contain much higher levels of omega-3 fatty acids than normal. The same effect has been found with vitamin D when chickens eat vitamin-D-enriched feed.
These factors can make the shade lighter or darker but not necessarily change the color itself. The breed is still the main factor when it comes to egg color.
Brown Eggs vs. White Eggs: Nutritional Content
“There is no real nutritional difference between those two [colors] of eggs,” says Rachel Daniels, MS, RD, senior director of nutrition for Virtual Health Partners. Science backs that up: A 2010 study published in Poultry Science came to the same conclusion.
Regardless of their size, grade, or color, however, all eggs are essentially very similar as far as their nutritional content. A typical egg contains lots of vitamins, minerals, and high quality protein, all wrapped up into less than 80 calories.
There has still been no evidence to suggest that either white or brown eggs taste better overall compared to the other. This is despite one study suggesting that brown eggs are heavier than white eggs and have more shell and albumen (egg white). The research also indicates that brown eggs may also have less yolk.
