This study aimed to assess the methylation levels of specific DNA sequences from the nuclear and mitochondrial genomes related to the regulation of oxidative stress processes, mitochondrial function, and global methylation, such as GSTP1, D-loop, and LINE-1, in a population with ALS and to elucidate the relationship of these epigenetic mechanisms with the parameters of nutritional status and the progression of the disease. This evidence concerns the gene GSTP1 and amyotrophic lateral sclerosis.