Cognitive Impairment in Multiple Sclerosis Tied to Diet

A Mediterranean diet was associated with better cognition in people with multiple sclerosis (MS), preliminary data suggested.

Among 563 MS patients in a clinical cohort, higher adherence to a Mediterranean diet predicted a 20% lower risk for cognitive impairment (OR 0.80, 95% CI 0.73-0.89), reported Ilana Katz Sand, MD, of the Icahn School of Medicine at Mount Sinai in New York City, in an abstract released in advance of the American Academy of Neurology annual meeting.

The relationship was stronger for people with progressive MS than for those with relapsing-remitting disease. Adjusting for socioeconomic status, smoking, body mass index, high blood pressure, and exercise did not affect the association.

"Among health-related factors, the level of dietary alignment with the Mediterranean pattern was by far the strongest predictor of people's cognitive scores and whether they met the study criteria for cognitive impairment," Katz Sand said in a statement.

A Mediterranean diet pattern includes a high intake of vegetables, legumes, fruits, fish, and healthy fats like olive oil, and a low intake of dairy products, meat, and saturated fatty acids. Some studies have linked adherence to Mediterranean types of diets with better cognition in people without MS, but others have found no such relationship over time.

Previous research from Katz Sand and colleagues have linked Mediterranean diet scores with thalamic volume in people with early MS and with objective disability in a real-world MS cohort. Studies from other researchers have suggested that Mediterranean and Paleolithic diets could reduce fatigue and improve physical and mental quality of life for people with MS.

In the current study, Katz Sand and co-authors assessed 563 MS patients who completed the Mediterranean Diet Adherence Screener (MEDAS; scores range from 0-14, with higher scores indicating better adherence) and the Brief International Cognitive Assessment for MS (BICAMS) cognitive battery that included the Symbol Digit Modalities Test, the Hopkins Verbal Learning Test-Revised, and the CANTAB Paired Associates Learning test. Cognitive impairment was defined as scoring below the fifth percentile on two or three tests.

Mean patient age was 44, and 71% were women. Participants were divided into four groups; the lowest group (133 people) had MEDAS scores of 0-4 and the highest group (103 people) had MEDAS scores of 9 or higher.

The mean cognitive z-score was -0.67. Higher MEDAS scores independently predicted better cognition (β=0.20, P<0.001). Overall, 19% of participants had cognitive impairment, ranging from 34% in the lowest MEDAS group to 13% in the highest MEDAS group.

"After controlling for important potential confounders, we note a significant association between Mediterranean diet score and cognition in a representative sample of people with MS," the researchers wrote. "The strength of the relationship in progressive disease suggests the possibility of a neuroprotective mechanism."

Longer, well-designed interventional clinical trials are needed to confirm these results, Katz Sand noted.

"Cognitive difficulties are very common in MS and they often get worse over time, even with treatment with disease-modifying therapies," she said. "People living with MS are very interested in ways they can be proactive from a lifestyle perspective to help improve their outcomes."

Comment