One of the most overlooked supplements that everyone(athletes or not) should be taking is magnesium(Mg). There are over 300 bodily processes in which Mg is involved, including tons of enzymes.

This study showed a direct correlation between serum Mg levels and biomarkers for cardiovascular disease and type 2 diabetes. Specifically, subjects with high serum Mg levels had a 48% less chance for hypertension, a 69% lower chance for developing type 2 diabetes, and perhaps most importantly a 42% lower odds of calcification of coronary arteries!

Many athletes and competitors take compounds like androgens which have shown to increase chances of calcification so Mg should be a staple in your supplement regimen(along with vitamin K2). As far as which type of Mg, the amino acid chelates are the most bioavailable such as Mg bisglycinate, Mg citrate or malate, Mg taurinate and Mg orotate. The cheapest and most common form is MgO or magnesium oxide, which has terrible bioavailability. I personally use Mg bisglycinate at 600mg/d.