These findings add to the accumulating evidence that diet is important in MS, says the lead author, Ilana Katz Sand, MD, an associate professor of neurology at the Icahn School of Medicine and a neurologist at Mount Sinai in New York City. “After rigorously controlling for demographic and health-related factors, we noted a significant association between Mediterranean diet score and objectively captured disability in people with MS,” she says. “This study does help confirm what we’ve suspected from previous literature — that a person’s particular level of adherence to the Mediterranean diet seems to matter for outcomes of MS,” says Mary Rensel, MD, an assistant professor of medicine and the director of pediatric multiple sclerosis and wellness at the Mellen Center of the Cleveland Clinic in Ohio, who was not part of the research.
No Single Diet Has Been Shown to Improve MS
Researchers have been studying diet and MS for decades, says Dr. Rensel. Although there’s been no single study (so far) that’s shown one nutritional pattern works for all people with MS, there’s evidence that nutritional intake and a healthy diet does matter as far as mood disorders, physical outcomes of MS, and how a person feels (quality of life) are concerned, she says. Because of that, and because people with MS are very interested in how what they eat impacts their condition, this is a much-needed study, says Rensel. The Mediterranean diet uses olive oil as the primary oil and emphasizes the intake of fruits, vegetables, legumes, nuts and seeds, moderate amounts of fish and dairy products, and limited amounts of red and processed meats and sugar.
Mediterranean Diet Associated With Improved Overall Health in People With and Without MS
Researchers in this study chose to evaluate the Mediterranean diet in people with MS for several reasons. For starters, it’s associated with improved general health outcomes, including the prevention of cardiometabolic conditions that are already adversely linked with the course of the disease. Cardiometabolic health includes several risk factors, including type 2 diabetes and insulin resistance, cardiovascular disease, cholesterol levels, high blood pressure, and overweight and obesity. Some lab studies have also suggested that key components of the diet, including omega-3-fatty acids and antioxidant-containing foods, have potential neuroprotective benefits in MS. In a randomized controlled pilot trial, published in the November 2019 Multiple Sclerosis and Related Disorders by the same team, a modified Mediterranean diet in MS showed promise: The people who stuck to the diet reported improvements in fatigue, impact of MS symptoms on everyday life, and stabilization of disability.
People With MS Who Closely Followed a Mediterranean Diet Had Less Disability
The study included 563 people with MS between ages 18 and 65, who completed the Mediterranean Diet Adherence Screener (MEDAS), which scores the consumption of healthy foods (such as olive oil, vegetables, whole grains) and avoidance of unhealthy ones (such as red meat and butter). The MS Functional Composite (MSFC) was tool used to objectively measure disability in MS, including cognition, arm coordination, and walking speed alterations. Patient-reported outcomes assessed physical impairment, fatigue, walking and cognitive dysfunction, depression, and anxiety. Researchers grouped participants according to their MEDAS scores, with a higher score indicating better adherence to the Mediterranean diet. The team found that higher scores were associated with better MSFC performance (meaning less disability), independent of demographic factors such as age, sex, race, ethnicity, and socioeconomic status, or other health conditions. Each MEDAS point score increase was linked to a 15 percent lower risk for MSFC impairment. “MEDAS was by far the best health-related predictor of MSFC,” the authors wrote. More closely following the Mediterranean diet was also associated with lower disability across all patient-reported outcomes, regardless of demographic factors or other health issues. Among patient-reported outcomes, depression had the strongest association with MEDAS scores. “Depression was worse among patients who use butter, drink sugary beverages, and consume less fish,” according to researchers.
The Million Dollar Question: Can Diet Change the Course of MS?
This study has several strengths that help further the research on the impact of diet on MS, says Rensel. “They used the Mediterranean Diet Adherence Screener (MEDAS), and then looked at covariates — socioeconomic, demographic, health related, and found that yes, if people were more adherent to the Mediterranean diet, they did have less physical disability from their MS, and it did seem related to their diet rather than other factors,” she says. Even with all the research on diet and MS, the “million-dollar question” has been, “Is eating a healthy diet enough to change the outcome of your MS?” says Rensel. Other studies have demonstrated that a composite healthy lifestyle lessens symptoms and disability, but does diet change the disease course of MS in 5, 10, or 20 years? she asks. “They’ve chipped away at that question with this very detailed study,” says Rensel.
People With MS With Lower Income or Less Education Are Less Likely to Follow the Mediterranean Diet
The findings also suggested that how adherent people were to the diet was related to socioeconomic status, says Rensel. This confirms what has been seen in other conditions — income, where a person lives, and education can all impact a person’s ability to get healthy food, she says. “There’s more to be learned about this — what types of support and resources can we offer to help everyone have access to more nutritious foods,” she says.
Researchers Plan Larger Studies on Diet and MS
“We are currently conducting longitudinal studies on this topic to help us understand the impact of diet in MS over time, one of which aims to further investigate potential mechanisms for these observed effects,” says Dr. Katz Sand. Going forward, the team plans to conduct larger interventional studies that build on their findings thus far.
Should People With MS Eat a Mediterranean Diet?
“We do not currently have enough evidence to recommend one particular dietary pattern definitively over another,” says Katz Sand. “However, we are accumulating evidence, strengthened by this paper, that diet is important in MS,” she says. Katz Sand is part of the National Multiple Sclerosis Society’s Wellness Research Working Group, and she encourages her patients to follow the organization’s general healthy-eating guidelines. “This includes things like preparing meals at home when possible, trying to incorporate vegetables and fruits, and limiting intake of ultra-processed items as much as possible. In my experience, a few small changes can go a long way in terms of how someone feels each day,” she says. At the Cleveland Clinic, providers recommend the Mediterranean diet for people with MS, says Rensel. “There’s so much literature behind the benefits of the diet, including improved mortality, a reduced risk of cardiovascular diseases, neurodegenerative diseases, and some types of cancer,” she says. For the general population and for people with MS, it’s never too late or too early to optimize your diet and lifestyle to improve your overall health, says Rensel. These behaviors should be used along with, not in place of, any MS medications that your doctor prescribes, she adds.
