due to a potential neuroprotective mechanism, according to findings of a study that was released early, ahead of presentation at the annual meting of the American Academy of Neurology.
“We were most surprised by the magnitude of the results,” said Ilana Katz Sand, MD, associate professor of neurology at the Corinne Goldsmith Dickinson Center for MS at Mount Sinai in New York. “We hypothesized a significant association between Mediterranean diet and cognition in MS, but we did not anticipate the 20% absolute difference, particularly because we rigorously controlled the demographic and health-related factors, like socioeconomic status, body mass index, and exercise habits.”
Corinne Goldsmith Dickinson Center for MS at Mount Sinai
Dr. Ilana Katz Sand
The Mediterranean diet consists of predominately vegetables, fruits, legumes, fish, and healthy fats while minimizing the consumption of dairy products, meats, and saturated acids. Previous literature has drawn an association between diet and MS symptomology, notably with regard to the Mediterranean diet. These studies indicated a connection between thalamic volume in patients with early MS as well as objectively captured MS-related disability. In this study, researchers have continued their investigation by exploring how the Mediterranean diet affects cognition.
In this cross-sectional observational study, investigators evaluated 563 people with MS ranging in age from 18 to 65 years (n = 563; 71% women; aged 44.2 ± 11.3 years). To accomplish this task, researchers conducted a retrospective chart review capturing data from patients with MS who had undergone neurobehavioral screenings. Qualifying subjects completed the Mediterranean Diet Adherence Screener (MEDAS) to determine the extent to which they adhered to the Mediterranean diet. A 14-item questionnaire, MEDAS assess a person’s usual intake of healthful foods such as vegetables and olive oil, as well as minimization of unhealthy foods such as butter and red meat. They also completed an analogue of the CICMAS cognitive battery comprised of a composite of Symbol Digit Modalities Test, Hopkins Verbal Learning Test, Revised, and CANTAB Paired Associate Learning.
Researchers evaluated patient-reported outcomes adjusted based on demographics (i.e., age, sex, race, ethnicity, and socioeconomic status) and health-related factors. These elements included body mass index, exercise, sleep disturbance, hypertension, diabetes, hyperlipidemia, and smoking.
The study excluded patients who had another primary neurological condition in addition to MS (n = 24), serious psychiatric illness such as schizophrenia (n = 5) or clinical relapse within 6 weeks (n = 2), or missing data (n = 13).
Based on the diet scores, investigators stratified participants into four groups. Those with the scores ranging from 0 to 4 were classified into the lowest group, while scores of 9 or greater qualified participants for the high group.
Investigators observed a significant association between a higher Mediterranean diet score and condition in the population sampled. They found a mean z-score of –0.67 (0.95). In addition, a higher MEDAS proved an independent indicator of better cognition (B = 0.08 [95% confidence interval (CI), 0.05, 0.11], beta = 0.20, P < .001). In fact, a high MEDAS independently correlated to a 20% lower risk for cognitive impairment (odds ratio [OR] = .80 {95% CI, 0.73, 0.89}, P < .001). Ultimately, the study’s findings demonstrated MEDAS served as the strongest health-related indicator of z-score and cognitive impairment. Moreover, dietary modification based on effect suggested stronger associations between diet and cognition with progressive disease as opposed to relapsing disease, as noted by the relationship between the z-score and cognition.
“Further research is needed,” Dr. Katz Sand said. “But because the progressive phenotype reflects more prominent neurodegeneration, the greater observed effect size in those with progressive MS suggests a potential neuroprotective mechanism.”
This study was funded in part by an Irma T. Hirschl/Monique Weill-Caulier Research Award to Dr. Katz Sand. Dr. Katz Sand and coauthors also received funding from the National Multiple Sclerosis Society.