Question

why does the hair become white or grey

Answer 1

because we have less proteins and minerals in our body

Answer 2

As we get older, the pigment cells in our hair follicles gradually die. When there are fewer pigment cells in a hair follicle, that strand of hair will no longer contain as much melanin and will become a more transparent color — like gray, silver, or white — as it grows. ... People can get gray hair at any age