In particular, consuming more high-fat dairy products was associated with a lower volume of brain lesions in patients, while omega 3 from fish was found to preserve the integrity of white matter — the region of the brain that is mostly affected by MS.
The study, “Dietary Factors and MRI Metrics in Early Multiple Sclerosis,” was published in Multiple Sclerosis and Related Disorders.
Traditional Mediterranean diets include whole, minimally processed plant foods including cereal grains, legumes, vegetables, fruits, nuts, and fish, with small amounts of red meat, milk, dairy products, and red wine.
The DASH diet, another whole-food-based diet, includes whole grains, fruit, vegetables, poultry, fish, and low-fat dairy products, with minimal fats, red meat, sweets, and sugar-sweetened beverages.
In combination, these diets promote the consumption of foods thought to benefit neurodegenerative disorders. This originated the MIND diet, whose adherence is based on the consumption of “brain healthy” and “unhealthy” foods. The former include green leafy vegetables, other vegetables, nuts, berries, beans, whole grains, seafood, poultry, olive oil, and wine. In contrast, “unhealthy foods” include red meat, butter or margarine, cheese, pastries or sweets, and fried or fast foods.
“Higher adherence to the MIND dietary pattern has been linked to lower incidence of Alzheimer’s disease, better cognitive outcomes in older adults, and reduced incidence/progression of parkinsonism in older adults,” the researchers wrote.
In addition, previous studies have linked the MIND diet to lower risks of cognitive decline and dementia in older adults. Although aging and MS occur for distinct reasons, similarities between them suggest that diet also may benefit people with MS.
A team of researchers in the United States set out to investigate whether diet maintains brain integrity in people with early MS and protects them against future disability. They did this by assessing the link between diet and MRI assessments such as the number of brain lesions, white matter and grey matter integrity, and thalamus’ volume.
The brain’s grey matter is where the cell bodies of nerve cells reside, whereas white matter is composed mainly of brain fibers covered by a fatty and whiteish material called the myelin sheath. The thalamus is a small part of the brain just above the brainstem that relays movement and sensory signals.
A total of 185 people diagnosed with relapsing-remitting MS or clinically isolated syndrome from October 2016 to December 2017 were included in the study.
Patients had a mean age of 34 years, 66% were women, 20% Black or African American, and 22% Hispanic or Latino. Approximately two years had elapsed since their diagnoses.
Participants completed a detailed food frequency questionnaire that provided information about their dietary patterns and allowed the researchers to estimate their consumption of key nutrients such as omega-3 fatty acids. Their diets were assigned scores based on how many healthy or unhealthy foods they ate. The maximum score was 15 points, indicating maximum adherence to the MIND diet.
The average MIND diet score was 8.5, but ranged from 4 to 12. Participants with higher scores tended to be older, non-Hispanic white, non-smokers, less overweight, and more active than those with lower scores.
After accounting for confounding factors such as age, sex, ethnicity and race, body mass index and physical activity, years of diagnosis, and use of disease modifying therapies, a significant association was found between higher adherence to the MIND diet and a greater volume of the thalamus. This association was independent of the number of brain lesions a patient had.
Other outcomes also tended to be better in patients with higher scores, but such associations failed to reach statistical significance, the team noted.
The researchers then examined if there were particular foods in the MIND diet associated with brain integrity outcomes.
Contrasting with previous research, a significant association was observed between eating more full-fat dairy products and lower brain lesion volumes. “The preclinical literature, while limited, might have led to the expectation of the opposite relationship,” the researchers wrote, adding that this effect might be driven by an increase in Lactobacillus bacteria in the gut, “which have been suggested to be of potential benefit in MS.”
Higher intakes of omega-3 fatty acids from fish also were associated slightly with higher white matter integrity. And, “unexpectedly,” higher intakes of polyunsaturated fatty acids (PUFAs) were associated with higher brain lesion volumes.
While the mechanisms through which omega-3 protects white matter are unclear, the findings parallel “previous work demonstrating a significant protective effect of PUFAs on cognition in older adults which is mediated by white matter microstructural integrity,” the investigators wrote.
The researchers pointed to several study limitations, such as the use of questionnaire-based diet assessments, the inclusion of participants with early MS only, the lack of a control group, and the assessment of diet at a single time point.
Still, “this first study linking diet with MRI metrics in MS provides valuable guidance regarding future directions on this critically important topic to the MS community,” the team wrote.
