The impact of dietary factors and circadian rhythms on fatigue in multiple sclerosis

Background Multiple sclerosis (MS) is a chronic inflammatory and autoimmune disease that affects the central nervous system. Fatigue is a common disabling symptom experienced by patients with MS, but is difficult to treat efficiently. Recent studies suggest that food intake could impact fatigue. When assessing eating habits, researchers have classically focused on food content (i.e., calorie and macronutrient intake), but a new dimension is being explored for other diseases such as the metabolic syndrome, i.e. the timing of caloric intake. The reason behind this increased interest in eating patterns is that the timing of caloric intake over the 24h cycle might interact with the circadian rhythm and have additional effects on metabolism and neurological disease. Aims We aimed to assess the relationship between the timing of food intake and fatigue among patients with MS. We hypothesized that eating duration impact fatigue in MS patients. Methods First, in a pilot survey of MS patients and healthy caregivers, we retrospectively assessed MS-related fatigue using the validated EMIF-SEP questionnaire. To evaluate eating duration, we used a dietary questionnaire measuring the eating habits specifically at what time they eat, drink, wake up and go to bed. Next, we conducted a prospective observational study on patients with relapsing remitting MS (RRMS) and assessed their fatigue with the EMIF-SEP questionnaire. Participants used a smartphone application to take timestamped pictures of consumed food items and drinks. The eating duration was the time interval between the 2.5th and 97.5th percentiles of all consumption entries over one month. Results In the survey, we recruited 10 caregivers and 32 MS patients (18 RRMS, 8 secondary progressive MS (SPMS), 3 primary progressive MS (PPMS) and 3 unspecified). Among caregivers the mean EMIF-SEP fatigue score was 34.5 (± 22.3) with a mean eating duration during weekdays of 12.5h (± 1.6) and during weekends of 11.1h (± 1.0). Among MS patients the mean EMIF-SEP score was 39.1 (± 18.8) with a mean eating duration during weekdays of 12.7h (± 2.0) and during weekend of 10.8h (± 2.2). There was no significant correlation between the eating duration and fatigue in MS, and a negative correlation among caregivers (Pearson correlation coefficient ρ = -0.62, p = 0.05). In the prospective observational study, 34 participants with RRMS were recruited. The mean EMIF-SEP score was 35.8 (± 19.6) and they ate over a mean duration of 14h22 (± 01:26). The eating duration was negatively correlated with MS-related fatigue (ρ = –0.42, p = 0.02). Conclusion We did not observe a correlation between fatigue and eating duration in the pilot survey in MS patients, but a borderline significant negative correlation between fatigue and eating duration in caregivers. In the prospective observational study, we further observed a negative correlation between fatigue and eating duration in RRMS. This study opens new perspectives on the investigation of the impact of eating patterns on fatigue in MS but also on other symptoms and even on other diseases