*4.2.7 Neurological effect*

Fluoride is a powerful toxin of the central nervous system and adversely affects the brain functioning even at low doses [32]. It can induce neuron apoptosis and decreased cerebral functions, impaired memory and learning ability [33, 34]. F ions bind to antioxidants such as N-acetyl cysteine (NAC), glutathione (GSH), and other free-radical-defeating enzymes. This causes oxidative stress and eventually cell death [35]. The lack of a compensating antioxidant system combined with oxidative stress caused by increased free radicals plays a significant role in the onset of nerve cell membrane damage, particularly through enhanced lipid peroxidation. Several studies have reported the effects of fluoride in drinking water on cognitive capacities, and IQ reductions were observed at water-fluoride concentrations of about 1mg/L and above [36].
