Recently, Seiichiro Ii et al. published a paper [5] in which they claimed to be able to measure locally the magnetic moment of iron at different types of grain boundaries employing electron energy loss spectrometry in a transmission electron microscope. They used the white line ratio of the iron L 2,3 -edge which is not only very sensitive to magnetic transitions but also to the oxidation state of the iron atoms inside the probed volume. In the following we will demonstrate that the discussed data do not only allow interpretation of the L 3 /L 2 ratio in terms of an enhancement of the magnetic moment but can also be interpreted in terms of oxygen diffusion into the grain boundaries.