Other bodily fluids are used to sustain our life (and the life of a child before birth).
Blood, for example, is an essential fluid for both of us, and signifies quite a lot in life. Yet, having jewellery made of your own blood would generally be consdiered a bit weird and gross.
Equally, having jewellery made of a soggy biscuit, or some SMA, which may have been used to feed a tiny baby would seem odd.