A Mediterranean diet may help multiple sclerosis (MS) patients ward off damage to their thinking skills.

New research finds that a diet rich in veggies, fruit, fish and healthy fat reduced their risk of developing memory loss as well as losing the ability to concentrate, learn new things or make decisions.

A loss of such key mental skills, or “cognitive impairment,” is a common feature of MS, a neurological disease that short circuits critical communication between the brain and body.

But the new analysis of diet and mental status among 563 people with MS linked the Mediterranean diet to a 20% lower risk for cognitive difficulties.

“Mediterranean diet is a broad term and there are geographical variations,” said lead author Dr. Ilana Katz Sand, an associate professor of neurology at Icahn School of Medicine at Mount Sinai in New York City. “However, it refers to an overall pattern that favors fruits, vegetables, olive oil, nuts, fish, and whole grains and limits meats — particularly red meat — baked goods, and highly processed foods.”

Prior research has suggested that Mediterranean diets “have broad health benefits,” Katz Sand added, including some protection against heart disease, obesity, cancer, diabetes, Alzheimer’s and overall mental health decline.

“In this study,” she said, “we demonstrate a significant positive association between the level of alignment of one’s diet with a Mediterranean pattern and better cognition in people with MS.”

Katz Sand stressed that the protective association “remained strong” even after her team accounted for factors that can influence mental status. Those included age, gender, race, ethnicity, income, obesity, diabetes, smoking history, exercise habits and high blood pressure.

About 7 in 10 of the study participants were women, at an average age of 44. All completed a nutrition assessment and a screening for mental sharpness, or acuity.

About 19% of the MS patients had already experienced some degree of mental decline.

“When we grouped people according to their Mediterranean diet score, those in the lowest (scoring) group were far more likely to meet our criteria for cognitive impairment than those in the higher (scoring) groups,” Katz Sand said.

More research will be required to fully understand why such a diet would be protective among MS patients.

One possibility: The benefit may owe to “the chemical structure of the foods themselves, and the effects of these foods on the composition and function of the gut microbiota, (meaning) the bacteria that live in the gut,” she suggested.

In sum, she noted, the metabolites produced by digestion may have “distant effects outside the gut, including the ability to protect the brain from physical and cognitive decline due to MS.”

Katz Sand stressed that the findings are “observational,” reflecting the cognitive status of each participant at one moment in time. In other words, the study cannot prove that a Mediterranean diet staves off progressive mental decline in MS patients.

“We are encouraged by these results, but because of the study design, we are not able to say for certain that if people make a change in their diet, that they will have better cognition going forward than if they did not make that change,” Katz Sand said. “Before we make recommendations that promise particular benefits for people living with MS, we need well-designed interventional studies that provide a high level of evidence.”

Connie Diekman, a former president of the Academy of Nutrition and Dietetics who reviewed the findings, agreed that more research is needed to understand how the eating regimen might help MS patients and whether it changes the course of the disease.

Diekman said the study adds to existing research and “appears to further the support for a Mediterranean-type diet,” both for MS patients and as “a positive for everyone.”

The researchers released their findings March 1 in advance of a presentation scheduled for late April at the American Academy of Neurology annual meeting, held in Boston and online. Research presented at meetings is typically considered preliminary until published in a peer-reviewed journal.

More information

There’s more about MS and nutrition at the National Multiple Sclerosis Society.

SOURCES: Ilana Katz Sand, MD, associate professor, neurology, Icahn School of Medicine at Mount Sinai, and associate director, Corinne Goldsmith Dickinson Center for MS at Mount Sinai, New York City; Connie Diekman, MEd, RD, food and nutrition consultant, St. Louis, and former president, Academy of Nutrition and Dietetics; presentation, American Academy of Neurology meeting, Boston and online, April 22 to 27, 2023