Dietary regimens and cognitive function in multiple sclerosis: a systematic review

Cognitive impairment is a common and debilitating complication of multiple sclerosis (MS), but non-pharmacological strategies such as diet for its management have not yet been fully explored. The aim of this review is to synthesize the evidence on the relationship between diet and cognitive outcomes in people with MS. Clinical interventional and observational studies evaluating the association between the diet and cognitive outcomes in MS were considered. The diets most frequently evaluated were Mediterranean (n = 3), modified Paleolithic/Wahls (n = 3), Swank (n = 1), ketogenic (n = 2), and time-restricted eating (n = 1). Other included studies investigated the broader association between overall dietary quality, healthy-eating patterns, and cognitive outcomes in MS patients. Trials of the Mediterranean diet have generally shown no significant cognitive improvements, although a recent study on a low-calorie Mediterranean diet, as well as observational studies, has reported increased processing speed, manual dexterity, and fewer cognitive complaints. The Wahls/Paleolithic interventions showed improvements in processing speed and mental cognition that were comparable to the Swank diet. Limited evidence from small studies suggested potential benefits of ketogenic and time-restricted diets, while findings were inconsistent for general healthy or high-fiber diets. Dietary interventions may hold promise as adjunctive strategies for cognitive health in MS; however, inconsistencies in study designs, cognitive measures, and intervention duration, combined with limited high-quality evidence, undermine strong recommendations, which warrant further evaluations.