I'm a bit late to the conversation but find the mention of extra metals amusing yet annoying every time it is mentioned where it seems that everyone assumes these is no metal in a human to begin with. So how many have forgotten basic biochemistry or even had any in high-school?
There is also the assumption that cybernetic entities are mostly metal when most in existence in our reality are constructed from polymers and some ceramics and metals.
The cores are of course silicon, with the more advanced examples using Field-Programmable-Gate-Arrays gluing together their multiple processor cores.
An except from a medical journal
Among the metals that are currently known to be essential for normal biological functions in humans are sodium (Na), potassium (K), magnesium (Mg), and calcium (Ca) that belong to main group of elements, and vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), molybdenum (Mo), and cadmium (Cd) that belong to transition metal group of elements in periodic table. Among these metals, the most notable that usually exist in the form of ions, are Fe, Co, Ni, Ca, Cu, Zn, and Cr. The deficiency of Fe and Co leads to anemia, that of Cu leads to brain and heart diseases and anemia, that of Zn leads to growth retardation and skin changes, that of Ca leads to bone deterioration, and that of Cr reduces the glucose tolerance.
Make note about Calcium is the main constituent of the bones making up a skeleton.
For some reason people forget that this element is a metal. Most likely because it is encountered as a mineral when combined with carbonates in bones, limestone or water scale.