Researchers studying the health risks posed by gadolinium, a toxic rare earth metal used in MRI scans, have found that oxalic acid, a molecule found in many foods, can generate nanoparticles of the metal in human tissues. In a new paper, Brent Wagner, MD sought to explain the formation of the nanoparticles, which have been associated with serious health problems in the kidneys and other organs. "The worst disease caused by MRI contrast agents is nephrogenic systemic fibrosis," he said. "People have succumbed after just a single dose." The condition can cause a thickening and hardening of the skin, heart...