People with multiple sclerosis who follow a Mediterranean diet may have a lower risk for problems with memory and thinking skills than those who do not follow the diet, according to a new study. 

The Mediterranean diet includes a high intake of vegetables, legumes, fruits, fish, and healthy fats such as olive oil, and a low intake of dairy products, meats, and saturated fatty acids. 

The study involved 563 people with MS. People completed a questionnaire to show how closely they followed the Mediterranean diet. They were assigned a score of zero to 14 based on their responses with higher scores given to those who more closely followed the diet. Researchers at the Icahn School of Medicine at Mount Sinai in New York, N.Y., then divided participants into four groups based on their diet scores, with the lowest group having scores of zero to four and the highest group having scores of nine or higher. 

Participants also took three tests assessing their thinking and memory skills. Cognitive impairment was defined as scoring less than the fifth percentile on two or three of the tests. A total of 108 people, or 19 percent, had cognitive impairment.

The researchers found that people who more closely followed the Mediterranean diet had a 20 percent lower risk for cognitive impairment than people who did not follow the diet. Among those in the lowest diet score group, 34 percent had cognitive impairment compared to 13 percent of people in the highest diet score group. The relationship was stronger among people with progressive MS than among those with relapsing-remitting MS.

Importantly, the results were the same when researchers rigorously adjusted for other factors that could affect the risk of cognitive impairment, such as socioeconomic status, smoking, body mass index, high blood pressure, and exercise.

The researchers noted that longer studies that follow people over time and well-designed interventional clinical trials are needed to confirm the results. A limitation of the study was that tests were taken only once.

The findings will be presented at the Academy of Neurology’s 75th annual meeting.