Relationship between zinc-related nutritional status and the progression of multiple sclerosis

Abstract

Background: Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system.

Objective: To investigate plasma and erythrocyte zinc status and its relationship to MS.

Methods: Cross-sectional study, including 98 participants, distributed in groups: case (MS, n = 49), diagnosed with MS and control (n = 49), matched by age and sex with the case group. Zinc was analyzed by flame atomic absorption spectrophotometry, and superoxide dismutase (SOD) activity by spectrophotometry.

Results: Mean plasma zinc was 94.6 (22.1) μg/dL for MS patients and 81.5 (31.3) μg/dL for control group, with statistical difference (p = 0.023). The mean erythrocyte zinc was 83.6 (41.6) µg/gHb for case group and 72.6 (31.5) µg/gHb for control. Erythrocyte SOD activity was above reference values, significantly different for MS patients (p = 0.003). There was a significant direct correlation between erythrocyte zinc and SOD (r = 0.835; p < 0.001). SOD showed inverse correlation with MS outbreaks (r = -0.317; p = 0.027).

Conclusion: Patients with MS have normal plasma and elevated erythrocyte zinc. Erythrocyte zinc showed positive correlation with SOD, which correlated inversely to outbreaks.

Keywords: Multiple sclerosis; Neurodegeneration; Nutritional status; Zinc.