Influence of micronutrients on anxiety and depression in patients with amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by a progressive loss of motor function, with respiratory failure representing the leading cause of death. Beyond motor deterioration, ALS involves extramotor manifestations, including prominent anxiety and depression symptoms. The intake of certain micronutrients has been associated with these emotional symptoms, due to their role in monoaminergic and peptidic neurotransmitter synthesis pathways; furthermore, these emotional symptoms can severely reduce patients' quality of life. Therefore, this study aims to analyze the relationship between the intake of key micronutrients related to neurotransmitter activity and anxiety and depression symptoms in ALS patients.

A cross-sectional study was conducted with 61 patients with bulbar- or spinal-onset ALS. Dietary micronutrient intake (iodine, magnesium, vitamin B6, vitamin B9, and vitamin C) was assessed using a seven-day dietary record and a Food Frequency Questionnaire. Depression was assessed using the ALS Depression Inventory-12 (ADI-12), while anxiety-related symptoms were assessed using the Beck Anxiety Inventory (BAI).

A path analysis was conducted to examine the statistical prediction of emotional measures from nutrient intake. The model showed a good fit to the data: NFI = 1.000, GFI = 1.000, and SRMR = 0.001. Considering the magnitude of the effect of the regression weights (β ≥ 0.14), depression scores exhibited exploratory associations with iodine (β = -0.21) and magnesium (β = 0.22), while vitamin B9 (β = -0.32) emerged as an inferentially significant predictor (p < 0.05). Anxiety-related symptom severity (BAI scores) showed exploratory associations with iodine (β = -0.31), vitamin B6 (β = 0.24), and vitamin C (β = -0.15), whereas depression scores (β = 0.51) were an inferentially significant predictor (p < 0.05), with 41% of explained variance.

In this sample, lower vitamin B9 intake was statistically associated with depression scores in patients with ALS, while lower iodine and higher magnesium intake showed exploratory associations. Regarding anxiety-related symptoms assessed using the Beck Anxiety Inventory (BAI), higher scores were statistically associated with lower iodine and vitamin C intake, higher vitamin B6 intake, and elevated depression scores, and showed exploratory associations with lower iodine and vitamin C intake, and higher vitamin B6 intake.