The subjects were then separated into four groups depending on their diet scores, with the lowest group scoring zero to four and the highest scoring nine or more.
Participants also underwent three examinations to investigate their reasoning and memory abilities. Cognitive impairment was defined as scores in the fifth percentile or lower on two or three of the tests.
Cognitive disabilities affected 108 people or 19% of the total.
The researchers discovered that persons who adhered more closely to the Mediterranean diet had a 20% lower risk of cognitive impairment than those who did not.
The lowest diet score group had 43 of 133 persons, or 34%, with cognitive impairment. Whereas, the highest diet score group had 13 of 103 people or 13%.
Those with progressive MS, in which the disease continuously worsens, had a stronger association than those with relapsing-remitting MS, in which the disease flares up and then goes into remission.
Moreover, Katz Sand observed, the results were the same after researchers meticulously controlled for other factors that could potentially increase the risk of cognitive impairment, such as socioeconomic status, smoking, body mass index, high blood pressure, and exercise.
“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.
Longer studies that track people over time as well as well-designed interventional clinical trials, she said, are needed to corroborate the findings. One disadvantage of the study was that tests were only given once.