**5. Selenium and other antioxidants in Parkinson**

Deficiency of the minerals and other antioxidants required for life are relatively uncommon, however, modest deficiency is very common and often not taken seriously. Selenium is an essential trace element which is necessary for growth and protein synthesis. Selenium protects cellular elements from oxidative damage and may participate in redox type reactions. Low plasma selenium concentrations are associated with subtle neurological impairments reflected in soft neurological signs (Shahar et al. 2010). A statistically significant increase in plasma Se was identified for PD patients (McIntosh et al. 2012). This has been evidenced by an increased lipid peroxidation and reduced glutathione levels (Delanty and Dichter, 2000) and high concentration of iron and free radical generation via autocatalytic mechanisms within neuro‐ melanin-containing catecholaminergic neurons in the substantia nigra. In addition, the observation that exogenous administration of cysteine, N-acetyl cysteine or glutathione decreased the neurotoxic effects of 6-hydroxydopamine in vitro and in vivo reinforces this hypothesis (Soto-Otero et al. 2000). McCann et al. (2011), tested whether selenium-dependent proteins that are essential from an evolutionary perspective are more resistant to selenium deficiency than those that are less essential. The authors demonstrated a highly sophisticated array of mechanisms at cellular and tissue levels that, when selenium is limited, protect essential selenium-dependent proteins at the expense of those that are nonessential. It was also found that mutations in selenium-dependent proteins that are lost on modest selenium deficiency result in characteristics shared by age-related diseases including cancer, heart disease, and loss of immune or brain function (McCann et al., 2011). It was concluded that taking a multivitamin that contains selenium is a good way to prevent deficiencies that, over time, can cause harm in ways that we are just beginning to understand.
