Preventive effect of coffee and tea on amyotrophic lateral sclerosis

Abstract

Pupillo et al. conducted a case-control study to verify the association between food intake and amyotrophic lateral sclerosis (ALS) (1). I have some comments about their findings with special reference to coffee and tea consumption, which are protective factors for ALS. The authors reported that odds ratios (ORs) (95% confidence intervals [CIs]) of coffee and tea 0.29 (0.14–0.60). Beghi et al. also conducted a hospital-based case-control study to investigate the association between coffee intake and ALS (2). They set three controls, and ORs of current coffee drinkers for ALS significantly decreased. This finding supports preventive effect of coffee intake on ALS risk, although causal association should be verified by longitudinal and interventional studies. Relating to the causal association, Fondell et al. conducted a pooled analysis of prospective studies to examine the association between consumption of caffeine, coffee and tea and risk of ALS (3). ALS events were defined as incidence or death. Adjusted relative risk (95% CI) of highest quintile of caffeine intake against lowest quintile for ALS events was 0.96 (0.81–1.16), and there were no significant associations of caffeine or caffeinated beverages with ALS events. Events of incidence and death should be separated for the analysis as further study, because incident study would be more preferable for the prevention of ALS. About the mechanism of the association, Sc and Muralidhara summarized health benefits and risks of coffee and caffeine for ALS, which was mainly derived from animal and cell models (4). Not only caffeine, but also chlorogenic acid, caffeic acid, and hydroxy hydroquinone were considered as beneficial effects for ALS, although there were also undesirable effects of excessive coffee intakes. I recommend a prospective human study for ALS incidence with dose-response relationship to speculate the mechanism of the association.