Objective:

Determine if a low-fat diet is effective at ameliorating fatigue in people with multiple sclerosis (PwMS) through a randomized controlled trial (RCT). Primary outcome is reduction in fatigue assessed via Modified Fatigue Impact Scale (MFIS) at 16 weeks.

Background:

Fatigue is a common, disabling symptom of multiple sclerosis (MS). A dietary intervention to improve fatigue is desirable given the minimal risk of adverse events.

Design/Methods:

PwMS were assigned to a low-fat diet (active) or wait-list (control) group. The active group received 4 weeks of data collection/nutrition counseling followed by adherence to the diet for 12 weeks. We measured diet adherence using monthly Food Frequency Questionnaire and 24-hr food recall. The principal statistical analysis used linear mixed models, with a random effect for subject to account for the within-subject correlation, in an intent-to-treat (ITT) framework to determine the effect of diet on the outcomes of MFIS and Fatigue Severity Scale (FSS). Sensitivity analysis was conducted by excluding potential outliers in both groups.

Results:

39 participants were recruited with 20 in the active group and 19 in the control group. At baseline, participants' mean age was 50 years (±12 years), mean BMI was 31 kg/m² (±7 kg/m²), and mean EDSS was 3.8 (±1.4). Mean MFIS decreased by -4.00 (95% CI: -12.04, 4.04) and mean FSS decreased by -0.41 (95% CI: -1.18, 0.36) from baseline to the end of the RCT in active group compared to control. Sensitivity analysis strengthened the magnitude of association with a mean MFIS decrease of -13.93 (95% CI: -20.65, -7.20) and mean FSS decrease of -1.22 (95% CI: -1.94, -0.50) in active group compared to control. Percent calories from fat decreased by 10.56% (95% CI: -18.50%, -2.97%) in active group compared to control.

Conclusions:

This 16-week long low-fat dietary intervention reduced the fatigue score significantly in the active group compared to controls.