Egg yolk colour, does indicate nutritional differences

Published 13 July 2020

Egg yolks will range in colour—from pale yellow to deep orange to even a bright red—based on a hen’s diet. Because free-range hens often eat more pigmented, nutritious foods that range from insects to grasses, eggs from these chickens often have richer-coloured yolks. On the other hand, conventional, grain-fed chickens will produce a lighter yellow yolks. As for those red yolks we mentioned? One chef—Dan Barber, executive chef of New York-based Blue Hill restaurants—worked with Cornell University researchers to develop a feed blend high in red peppers that allowed hens to produce strawberry-coloued yolks.

As for the difference in nutrients between yolk colours? The protein and fat counts will often remain the same regardless of yolk colour, but there can be up to a 100-fold increase in micronutrient value of certain antioxidant carotenoids like lutein and beta-carotene in yolks fed a more nutrient-dense diet (like in pasture-raised hens), according to a 2010 study published in the Journal of the Science of Food and Agriculture. Rich, dark yolks will contain more of these potent antioxidants: compounds which mop up harmful toxins that promote inflammation and fat storage. Other studies have indicated that the same healthy diet that produces richer-colored yolks results in eggs with higher levels of heart-healthy omega-3s and less cholesterol.