Science clarifies that eggshell color does not indicate nutritional quality

Scientific research and health organizations indicate that the color of an eggshell is not a reliable indicator of nutritional quality, freshness, or taste. The color of the shell is primarily determined by the genetics and breed of the hen. For instance, the Harvard School of Public Health notes that hens with light plumage typically lay white eggs, while those with reddish or brown plumage tend to lay brown eggs.

The USDA has also stated that nutrient levels do not differ significantly between white and brown eggs. While pigments like protoporfyrin IX contribute to brown coloration, factors such as the hen's age, diet, stress levels, and farming systems can influence the intensity of the shell color.

Health experts recommend that consumers focus on the origin, farming methods, and freshness of the product rather than shell color. In Italy, the Ministry of Health advises checking expiration dates and avoiding cracked shells, while European regulations set specific quality requirements for Category A eggs.