cyclezen

here are a couple of things you might wanna look at.

1st lets take out the issue of 'electrolytes' and other small mineral deficiences. That is something you'd have to verify, as you have noted you seem to have that covered.

1. check your saddle height against some of the conventional formulas... Same with saddle position...
combination of both (and leg/foot alignment) could a large factor in the problem. If you do find you;re well outside of settings some of the common formulas will recommend; do changes in small increments, less than 5mm, and ride for a few days, before making further changes. Large seat position/height changes can screw you up also.

2. canting - leg alignment. driving thru the pedal stroke with a leg/foot which is out of alignment can cause this as well. anything different than even pressure on shoe sole on the downward stroke, can cause real problems from the knee downward.
canting, wedging or 'shimming' for this would be a possible adjustment for alignment issues. Lemond LeWedges...
if you're compensating for alignment issues, this could be aggravating the calf problem.

Since you;re experiencing this running as well, you might want to go to a podiatrist first, then if orthotics are recommended for your athletic shoes, you might be able to use them also in your cycling shoes; or you can then use LEWedges to achieve the proper alignment in your cycling shoes.

Large differences in leg length (left to right) could also contribute to all the problems above, and so be at the root of your problem.