Effects of low calcium and magnesium dietary intake on the central nervous system tissues of rats and calcium-magnesium related disorders in the amyotrophic lateral sclerosis focus in the Kii Peninsula of Japan.

Current epidemiological investigations in the Western Pacific including the Kii Peninsula of Japan, have suggested that environmental factors contribute to the pathogenetic process of amyotrophic lateral sclerosis (ALS) and parkinsonism dementia (PD). The condition of unbalanced minerals (a low content of calcium and magnesium, and a high content of aluminum) found in soil and drinking water in all three ALS foci was experimentally mimicked in our studies using rats. In rat groups maintained on unbalanced mineral diets, the calcium and magnesium contents of bones were lower than those fed a standard diet. In addition, the calcium content of CNS tissues showed higher values in the unbalanced diet groups (especially in the spinal cord of the low calcium and magnesium plus high aluminum diet group) than those in the standard diet group. The calcium content of other soft tissues as well as the CNS of rats fed unbalanced mineral diets was also higher than those on the standard diet. The magnesium content of soft tissues and spinal cord of rats was markedly lower in the low calcium and magnesium plus high aluminum diet group than in the other groups. Examination of tissues from six Kii Peninsula patients with ALS showed an average magnesium concentration in 26 CNS regions (cortical gray matter, white matter, basal ganglia, brain stem, spinal cord) significantly lower than that for five neurologically normal controls. The average calcium concentration in gray matter of ALS cases was significantly higher than that of controls. Interestingly, only 120 cases of calcification of spinal ligaments have been reported worldwide, and of these, 26 of 28 cases of calcification of spinal in the Kii Peninsula have been found to overlap the same geographic focal region as ALS. We analyzed the magnesium content of seven spinal vertebrae and 10 spinal ligaments of patients with calcification of spinal ligaments and the calcium content of five spinal bones compared with controls. The calcification of spinal ligaments patients had lower values for magnesium contents of bones and ligaments compared to controls and the calcium content of bones in these patients was significantly lower than that of controls. These data suggest that low dietary intake of calcium and magnesium over an extended period of time may contribute to the pathogenesis of patients with ALS and calcification of spinal ligaments.