Q&A: 10 cancer-related misconceptions

Q: Does eating over-boiled eggs with a 'black layer' cause cancer?

A: The formation of the "black layer" of eggs is just a chemical process during cooking. It is non-toxic and will not cause cancer. During the long heating process, the amino acids in the protein will be decomposed to produce sulfide, while the egg yolk is rich in iron. Through the interaction between the sulfide and the iron element, ferrous sulfide is formed, which makes the original golden yolk into a bluish gray or even black green.