The phrase "less magnesium" means a smaller amount or lower level of the element called magnesium.
Sentences with «less magnesium»
Our diets are providing less magnesium than they used to. (magnesium.ca)
A diet high in fat may cause less magnesium to be absorbed. (mayoclinic.org)
All those factors contributing to magnesium depletion haven't gone away, so there's likely even less magnesium in our food today. (clearskinforever.net)