Dietary intake and nutritional status in multiple sclerosis and associations with disease phenotype and management: A...

Nutrition and diet are increasingly recognised as potential modulators of immune function in multiple sclerosis (MS), but human studies remain conflicting and often focus on single nutrients. We aimed to investigate dietary intake in people with MS versus matched controls and to examine associations between dietary components, phenotype, disability, severity, and disease‑modifying therapy (DMT) status.

In this cross-sectional case-control study, 270 adults with clinically confirmed MS and 255 originally age-matched controls completed a validated food-frequency questionnaire and provided clinical data. Exclusion of participants with invalid questionnaires partially disrupted the original matching, leaving residual imbalances in sex (67% female in MS vs 39% in controls) and BMI; analyses were therefore conducted as unmatched with adjustment for age, sex, and BMI. Comparisons between groups and associations between dietary components and clinical measures were analysed.

MS patients had lower body mass index and reported higher intake of vitamin D, β‑carotene, vitamins A, C, and E, folate, fruits, and vegetables, and lower intake of bread, pasta, rice, total fat, saturated fat, cholesterol and sodium compared with controls. Overall dietary composition differed significantly between MS patients and controls in multivariate analyses, including after adjustment for age and sex (PERMANOVA P = 0.046). In adjusted logistic regression, only vitamin D supplementation remained independently associated with MS status (P = 0.006). Within the MS cohort, dietary components including vitamin B6, polyunsaturated fat and vitamin A were not significantly associated with disability or progressive disease in adjusted analyses; the progressive-MS subgroup (n = 26) was small and these exploratory results should be interpreted with caution.

MS patients showed a different dietary pattern characterised by higher micronutrient and supplement intake, most likely reflecting post-diagnosis behavioural change rather than a pre-existing dietary difference. These are hypothesis-generating observations from an unmatched cross-sectional study with residual confounding; they do not support causal inference and should not inform dietary prescriptions without prospective confirmatory evidence.