High dietary fish intake may slow disability progression in multiple sclerosis

Consuming lean and oily fish may slow multiple sclerosis progression, but more research needed

Eating more lean and oily fish may slow the progression of disability in people with multiple sclerosis (MS), concludes a new study in the Journal of Neurology Neurosurgery & Psychiatry. Researchers believe the anti-inflammatory and brain-protective nutrients of fish are key, adding weight to the idea that diet plays a big role in managing MS and similar diseases.

While earlier research has linked fish consumption with lower disability levels in MS, few studies have explored whether it might actually slow the progression of the disease. To investigate this, the researchers analyzed data from 2,719 newly diagnosed MS patients – averaging 38 years old – from Sweden’s nationwide Epidemiologic Investigation of Multiple Sclerosis (EIMS) study, conducted between April 2005 and June 2015.

At the study’s start, every participant detailed their lifestyle habits and environmental exposures – including how often they ate lean and oily fish. Their fish intake was sorted into three groups: rarely, one to three times a month, and weekly and then scored from 2 to 6 based on whether they consumed lean fish, oily fish or both. Meanwhile, researchers tracked each participant’s disease progression for up to 15 years using the Expanded Disability Status Scale (EDSS) through the Swedish MS Registry.

Trend analysis confirmed that the more lean and oily fish consumed, the lower the risk of confirmed disability worsening. At diagnosis, those with the highest fish consumption saw a 44 percent lower risk of disability worsening, a 45 percent lower chance of reaching EDSS 3 and a 43 percent lower risk of progressing to EDSS 4 compared to participants who ate little or no fish.

In 2021, 1719 participants completed an online follow-up questionnaire that assessed changes in fish intake over time. Some 412 (24 percent) had altered their fish consumption: 288 had increased it; 124 had decreased it.

Those who increased their score from 2–3 to a score of 5–6 within five years after diagnosis (133) had a 20 percent lower risk of confirmed disability worsening, compared with those who continued to eat little or no fish (400).

Only 16 participants increased their fish consumption from a baseline score of 2 to a score of 5–6, but they had a 59 percent lower risk of confirmed disability worsening, compared with those who remained at the lowest level of consumption (101).

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The findings held even when the potentially influential factors of physical activity, weight (BMI), smoking, alcohol intake, and sun exposure were accounted for. They also remained similar when further adjustment was made for vitamin D levels.

However, the researchers caution that this observational study can’t prove that fish directly slows MS progression. More research is needed to confirm the findings and uncover the biological mechanisms.

“While omega-3 fatty acids, predominantly found in oily fish, may contribute to reduced disability progression, the beneficial effects observed from lean fish consumption suggest that other factors may also play a significant role,” wrote the researchers. “One such factor is taurine, an amino acid found in significant amounts in fish and seafood.”

Nonetheless, the researchers conclude that the results “underscore the potential role of diet, particularly fish consumption, as a modifiable factor that could complement existing therapeutic strategies for MS.”

Read the full study.