"The resulting correlations suggest that mortality from Parkinsonism, multiple sclerosis and amyotrophic lateral sclerosis occurs most often in recently glaciated, Iodine deficient regions, that were formerly marked by elevated goiter prevalence.
Conclusions. Long-term Iodine deficiency appears linked to abnormalities in the dopaminergic system that include an increased number of dopamine receptors. It is argued that this raises susceptibility to dopamine oxidation which, in turn, causes deficiencies of the antioxidant enzymes Cu/Zn superoxide dismutase, glutathione peroxidase and catalase. Dopamine deficiency also leads to elevated cytotoxic glutamate levels. Implications of the iodine-dopachrome-glutamate hypothesis, for treatment of these three neurologic disorders, are then discussed. Possible interventions include the use of levodopa, vitamin B3, Coenzyme Q10, various antioxidants, amino acids, Iodine and glutamate antagonists..."
"....The hypothesis that Parkinson’s disease may be linked to soil and hence dietary iodine deficiency, associated with glaciation, is not new. In 1987, de Pedro4 concluded that Parkinsonism had the strongest links with “Early life exposure to a geochemical imbalance, related to the last glaciation, associated to iodine washing out, present in soil, water and diet.” He reached this conclusion based on Parkinson’s disease prevalence and mortality in selected age groups and similarities between current levodopa use and goiter distribution, during the period 1920 to 1935. As early as 1959, Warren18 also argued that multiple sclerosis was more common in regions that had suffered recent continental glaciations, where it tends to develop most frequently in individuals who, as newborns, were fed milk from iodine deficient cows.19 It has been hypothesized that a lack of iodine in fodder deprives cattle of thyroxine, a deficiency which in turn prevents the conversion of carotene to vitamin A. Milk short of this vitamin also lacks the essential fatty acids because the latter, which form the main constituents of the myelin sheath, are oxidized rapidly in the absence of vitamin A. Certainly, a thyroid deficiency in rats has been liked to reduced myelin formation."