Dietary intake and zinc status in amyotrophic lateral sclerosis

Abstract

Background: There is considerable evidence that abnormal zinc homeostasis is related to amyotrophic lateral sclerosis (ALS) pathogenesis, and malnutrition is an independent prognostic factor for worsened survival of ALS patients. Objective: To evaluate the dietary intake and zinc status in patients with ALS, treated in a specialized outpatient facility in Natal, Brazil. Methods: Twenty patients with ALS (case group) and 37 healthy subjects (control group) were included. Clinical and anthropometric assessments were carried out and dietary intake was obtained from two 24-hour recalls. Plasma and urinary zinc concentrations were determined by atomic absorption spectrophotometry. Results: Most of the participants were eutrophic. Mean energy, protein, carbohydrate and fat intake was significantly lower for the case group. There was greater prevalence of inadequate zinc intake in the case group (35%) compared to controls (27%). Mean plasma zinc was significantly lower in the case group than in controls (77.13 ± 22.21 vs 87.84 ± 17.44 µgZn/dl). Urinary zinc did not differ significantly between cases and controls. In the case group, plasma and urinary zinc concentrations were below reference values in 50.0% and 52.6% of patients, respectively. Conclusion: A large portion of patients with ALS exhibited poor dietary intake and changes in body zinc status. The zinc deficiency found in half of the ALS patients may contribute to a worsened prognosis and should be the target of nutritional intervention that aims to correct this deficiency.