The association of serum carnitine levels with severity of fatigue in patients with multiple sclerosis: A pilot study

Background: Fatigue is a common complaint of patients with multiple sclerosis (MS), adversely affecting their quality of life. There is a lot of evidence showing that carnitine deficiency is linked to fatigue development and severity in some conditions. This study aimed to evaluate the association between free L-carnitine serum levels and the severity of fatigue in patients with MS. Methods: This case-control study included 30 patients with relapsing-remitting MS (RRMS) in two age-matched equal-number groups according to the presence or absence of fatigue. Fatigue was scored using the valid questionnaire of Fatigue Severity Scale (FSS) and serum level of free L-carnitine was measured simultaneously. Finally, the association between serum level of free L-carnitine and fatigue severity was evaluated in patients with MS. Results: The mean value of FSS in patients with fatigue was 48.80 ± 8.55, which was nearly two-fold higher than the group without fatigue. We found a significant correlation between the serum level of free L-carnitine and FSS and showed that the patients with fatigue had a significantly lower serum level of free L-carnitine compared to patients without fatigue (P < 0.001). Conclusion: Present study demonstrated that patients with lower serum levels of free L-carnitine were more likely to experience fatigue. We recommend that a higher dietary intake of carnitine might be a useful complementary treatment for MS-related fatigue.