What's in an egg?
Nutritional Value
 
Eggs are loaded with proteins, vitamins, minerals, good fats and various
trace nutrients. An average large egg contains 77 calories, 5 grams of
fat and 6 grams of protein with all 9 essential amino acids. They are
rich in iron, phosphorous, selenium and vitamins A, B12, B2 and B5.
 
What is that red spot on my yolk?
 
Blood or meat spots, occasionally found on an egg yolk, are an error on the part of the hen. They do not indicate a fertilized egg.  They are caused by the rupture of a blood vessel during formation.  Blood spots appear more often in brown eggs than white ones.  They are perfectly safe.
 
What is that white stringy thing inside my egg?
 
A chalaza (plural chalazae) is a structure inside an egg that helps to keep the yolk in place. It looks like a little stringy white rope inside the egg. The structure is perfectly safe to eat.