Certain diets may support thinking skills in people with MS, review finds

Certain diets may support cognitive function in people with multiple sclerosis (MS), according to a systematic review of available studies.

Studies of the low-fat Swank and Wahls diets reported improvements in processing speed and self-perceived cognitive function, although the evidence was limited. Evidence for the Mediterranean diet was mixed, while small studies suggested possible benefits from ketogenic and time-restricted eating approaches.

“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,” the researchers wrote.

The study, “Dietary regimens and cognitive function in multiple sclerosis: a systematic review,” was published in the journal Brain, Behavior, & Immunity – Health.

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Cognitive problems common in people with MS

Cognitive impairment affects an estimated 40% to 70% of people living with MS, a chronic immune-mediated disease that causes inflammation and damage in the brain and spinal cord, disrupting communication between nerve cells.

The area of cognition most commonly affected is information processing speed, but people with MS also often report issues with memory, attention, learning, and executive function — the mental skills involved in planning, organizing, and problem-solving. These changes can interfere with work, social activities, treatment adherence, and overall quality of life.

Although disease-modifying therapies (DMTs) can reduce relapses and slow disability progression as part of MS treatment, few therapies specifically target cognitive decline. While no diet can cure MS or replace DMTs, healthy eating habits may help ease symptoms and slow disease progression. This has prompted researchers to investigate whether certain dietary patterns could be used alongside DMTs to help manage cognitive problems.

To assess the effects of different dietary regimens on cognitive function in MS, a team led by researchers in Iran reviewed studies identified in searches conducted through Sept. 20, 2025. Sixteen studies, reported in 18 scientific papers, met the inclusion criteria.

Five of the 16 studies were randomized controlled trials, meaning participants were randomly assigned to different dietary interventions or comparison groups. Four were nonrandomized intervention studies, and seven were observational studies. Most intervention studies lasted from eight weeks to one year.

The Mediterranean diet, rich in fruits, vegetables, whole grains, legumes, fish, and olive oil, was the one of the dietary approaches most frequently studied. Studies also evaluated the Wahls diet, a modified Paleo diet that emphasizes vegetables, fruits, and high-quality proteins while excluding grains, legumes, eggs, dairy products, and processed foods, and the Swank diet, which severely limits saturated fat while encouraging intake of whole grains, fruits, and vegetables intake.

Other intervention studies examined the ketogenic diet, a very low-carbohydrate, high-fat eating plan; time-restricted eating, which limits food intake to a specific daily window; and an app-based nutrition program designed to increase fruit and vegetable intake. Several observational studies explored broader associations between healthy-eating patterns and cognitive outcomes in people with MS.

Wahls and Swank diets showed the clearest benefits

Studies evaluating the Wahls and Swank diets reported improvements in processing speed and self-perceived cognitive function. In the randomized trial comparing the two diets, improvements were similar between the groups, suggesting that shared features may be more important than the specific diet followed. However, the evidence was limited.

Findings for the Mediterranean diet were more mixed. Two randomized clinical trials found no significant improvements in cognitive performance compared with control diets. However, a more recent trial reported improvements in processing speed and manual dexterity among overweight participants following three calorie-restricted Mediterranean diets. Observational data also linked greater adherence to the Mediterranean diet with fewer cognitive complaints and better processing speed.

Evidence from small studies suggested possible cognitive benefits from ketogenic and time-restricted eating approaches, but the evidence remains too limited and inconsistent to draw firm conclusions.

Findings for generally healthy or high-fiber eating patterns were also inconsistent. Some observational studies linked healthier eating patterns or higher fiber intake with fewer cognitive complaints, while others found no association.

“This systematic review suggests that dietary interventions may offer benefits for cognitive outcomes in MS, particularly in processing speed and self-perceived cognitive function,” the researchers wrote, cautioning that “the certainty of evidence is limited” by the small size of many studies, differences in dietary interventions and cognitive assessments, relatively short follow-up periods, and the large proportion of observational studies.

“Well-powered, methodologically rigorous randomized controlled trials with standardized cognitive outcome measures are required before firm clinical recommendations can be made,” the team concluded.