Specific dietary interventions, particularly the low-fat Swank and Wahls diets, may support cognitive function and improve processing speed in people with multiple sclerosis, according to a systematic review published in the journal Brain, Behavior, & Immunity – Health. Researchers found that while these nutritional approaches hold promise as adjunctive strategies for cognitive health, inconsistencies in study designs and limited high-quality evidence mean that strong clinical recommendations require further evaluation.
Cognitive Impairment Challenges in Multiple Sclerosis
Cognitive impairment affects an estimated 40% to 70% of people living with multiple sclerosis, a chronic immune-mediated disease causing inflammation and damage in the brain and spinal cord, according to background data in the study. This disruption interferes with communication between nerve cells, most commonly impacting information processing speed. Patients also frequently report issues with memory, attention, learning, and executive function—the mental skills required for planning, organizing, and problem-solving.
These cognitive shifts can directly interfere with daily employment, social activities, treatment adherence, and overall quality of life. While disease-modifying therapies (DMTs) effectively reduce relapses and slow disability progression, few existing treatments specifically target cognitive decline. Because no diet can cure multiple sclerosis or replace disease-modifying therapies, researchers are investigating whether healthy eating habits might help ease symptoms and slow disease progression when used alongside standard medical care.
Did you know? Information processing speed is the single most common cognitive domain affected in multiple sclerosis, impacting everything from workplace productivity to social conversations.
Evaluating 16 Studies on Dietary Regimens
To assess the effects of different eating patterns on cognitive function, a team led by researchers in Iran reviewed scientific literature identified in searches conducted through Sept. 20, 2025. Out of the search results, 16 studies reported in 18 scientific papers met the inclusion criteria for the systematic review. The evaluated research included five randomized controlled trials, four nonrandomized intervention studies, and seven observational studies.
Most of the active intervention studies monitored participants for a duration lasting anywhere from eight weeks to one year. The dietary frameworks under review varied widely:
- Mediterranean Diet: Rich in fruits, vegetables, whole grains, legumes, fish, and olive oil.
- Wahls Diet: A modified Paleo diet emphasizing vegetables, fruits, and high-quality proteins while excluding grains, legumes, eggs, dairy products, and processed foods.
- Swank Diet: A plan that severely limits saturated fat while encouraging whole grains, fruits, and vegetables.
- Other Approaches: Included the very low-carbohydrate, high-fat ketogenic diet, time-restricted eating, an app-based nutrition program, and broader observational healthy-eating patterns.
Wahls and Swank Diets Show Clearer Cognitive Benefits
Studies evaluating the Wahls and Swank diets reported measurable improvements in processing speed and self-perceived cognitive function among participants. In a randomized trial directly comparing the two diets, improvements were similar between the groups. According to the study authors, this suggests that shared features across these dietary approaches may carry more importance than the specific diet followed, though the overall evidence remains limited.
In contrast, findings for the Mediterranean diet were more mixed. Two randomized clinical trials found no significant cognitive performance improvements when compared to control diets. However, a more recent trial highlighted by the researchers reported improvements in processing speed and manual dexterity among overweight participants who followed three calorie-restricted Mediterranean diets. Additionally, observational data linked greater adherence to the Mediterranean diet with fewer cognitive complaints and better processing speed.
Small-scale studies also pointed toward possible cognitive benefits from ketogenic and time-restricted eating approaches, but the researchers noted that this evidence remains too limited and inconsistent to draw firm conclusions. Results for generally healthy or high-fiber eating patterns were similarly mixed, with some observational studies noting fewer cognitive complaints while others found no association.
Call for Rigorous Randomized Trials
“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 in the published paper.
The team emphasized that the certainty of the current evidence is constrained by small sample sizes, varying dietary interventions, diverse cognitive assessments, and short follow-up periods. They concluded that well-powered, methodologically rigorous randomized controlled trials utilizing standardized cognitive outcome measures are essential before clinicians can issue firm dietary recommendations for multiple sclerosis management.
Pro Tip for Patients
Frequently Asked Questions
Can diet cure multiple sclerosis?
No. According to researchers, no diet can cure multiple sclerosis or replace established disease-modifying therapies, though certain eating patterns may help manage specific symptoms.
Which diets showed improvements in processing speed for MS?
Studies evaluating the low-fat Swank diet and the modified Paleo Wahls diet reported improvements in processing speed and self-perceived cognitive function.
Why is cognitive impairment common in multiple sclerosis?
Cognitive impairment affects an estimated 40% to 70% of people with multiple sclerosis because the chronic immune-mediated disease causes inflammation and damage in the brain and spinal cord, disrupting nerve cell communication.
Are there definitive clinical guidelines for MS diets yet?
Not yet. Researchers note that limited high-quality evidence, small study sizes, and inconsistent methodologies mean that further rigorous randomized controlled trials are needed before making firm clinical recommendations.
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