Science News: Nutritional and Metabolic Factors in Amyotrophic Lateral Sclerosis

Published January 08, 2024

Science News

Submitted by: Marcus Pai, MD
Edited by: Joshua Wilson, MD

Citation: Ludolph A, Dupuis L, Kasarskis E, et al. Nutritional and metabolic factors in amyotrophic lateral sclerosis. Nat Rev. Neurol. 2023 Sep;19(9):511-524. DOI: 10.1038/s41582-023-00845-8. PMID: 37500993.

Summary: Weight loss and metabolic abnormalities are common in patients with amyotrophic lateral sclerosis (ALS), often preceding symptom onset and predicting poorer outcomes. Clinical studies show premorbid weight loss, low body mass index, and loss of fat mass are associated with increased ALS risk and faster progression. Metabolic alterations such as reduced adiposity and cholesterol can be detected years before symptoms arise, indicating a causal role in disease pathogenesis rather than just a consequence of impairment. 

At the cellular level, ALS mutations directly disrupt metabolism and mitochondrial function. Mutant SOD1, TDP-43, FUS, and C9orf72 proteins impair bioenergetics in motor neurons, astrocytes, and skeletal muscle. These impairments contribute to energy depletion in metabolically demanding neurons, promoting degeneration. Systemically, mitochondrial dysfunction likely underlies the hypermetabolism observed in up to 68% of patients with ALS, where resting energy expenditure exceeds intake.

Preclinical models and early human trials suggest that nutritional interventions and compounds targeting cellular metabolism may be therapeutic in ALS. High-calorie diets extend survival in mice, while nutritional supplements appear to slow progression and reduce neurofilament levels in ALS patients. Drugs improving mitochondrial function and antioxidant pathways also show promise. Optimizing energy balance through diet alongside targeted metabolic treatments represents a promising dual approach to slowing disease progression.

Comments: This review provides a compelling look at the role of nutrition and metabolism in ALS; some limitations should be noted. The causes of hypermetabolism remain unclear, with the authors acknowledging that further research is needed to elucidate mechanisms. Human trials of nutritional interventions are still in the early phases, with optimal caloric intake and composition not yet defined. These trials' small sample sizes and short durations limit conclusions about long-term impacts on disease progression. Larger, longer studies will be essential to validate preliminary findings. The implications of this research are exciting. The evidence linking premorbid weight loss to ALS risk suggests a window for early intervention exists years before the onset of weakness. This raises the possibility that weight maintenance or metabolic treatments in high-risk individuals could help delay or prevent disease onset. The preclinical efficacy of nutritional and bioenergetic approaches also provides hope for slowing progression by enhancing energy supply and mitochondrial function in patients with ALS.