Cu,Zn-SODs, antioxidant enzymes, are linked to a number of diseases because they are essential for detoxifying ROS (Figure 5).The most common pathological conditions such as inflammatory bowel disease, obesity and its consequences—diabetes and hypertension—and chronic obstructive pulmonary disease, have been linked to changes in Cu,Zn-SOD (SOD1 and SOD3) activity and its expression. Here, SOD1 is linked to obesity due to melanocortin 4 receptor deficiency.