Eating more fish linked to slower MS disability progression: Study
Patients who ate more fish after diagnosis had less disability progression risk
People with multiple sclerosis (MS) who eat more fish are significantly less likely to see confirmed disability progression and the greater the intake, the lower the progression risk, a study in Sweden finds.
The dietary habits of patients were assessed at the time of their diagnosis and disability progression was tracked for up to 15 years. While greater benefits were observed in those who regularly ate fish since their diagnosis, patients who increased their fish intake in the years after being diagnosed also saw reductions in the risk of disability progression over those who continued to eat little to no fish.
The findings suggest “diet, particularly fish consumption, as a modifiable factor that could complement existing therapeutic strategies for MS,” the study’s researchers wrote in “Impact of fish consumption on disability progression in multiple sclerosis,” which was published in the Journal of Neurology, Neurosurgery and Psychiatry.
In MS, the immune system launches damaging attacks on the myelin sheath that protects nerve cells, causing symptoms. As damage accumulates over time, patients see worsening symptoms that cause disability levels to increase.
While disease-modifying therapies can slow the progression of disability, they cannot completely prevent it, so additional measures are needed to improve a person’s long-term outlook.
Growing evidence touts the benefits of a healthy diet in slowing disease progression. For example, a Mediterranean diet, rich in fish and other healthy foods like vegetables, is linked to less disability, with older patients also reporting better quality of life.
Eat more fish
Researchers at the Karolinska Institute in Sweden drew on data from 2,719 patients in a Swedish MS registry to explore whether eating more fish could slow disability progression. The registry included patients diagnosed between 2005 and 2015 who responded at enrollment to a questionnaire about environmental exposures and lifestyle habits. The patients were followed for up to 15 years.
The amount of fish they consumed had no impact on their disability levels, as assessed with the Expanded Disability Status Scale (EDSS), at the time of enrollment. However, those who reported eating fish weekly had a significantly lower risk of confirmed disability progression throughout the follow-up.
Specifically, eating lean fish each week such as cod, haddock, and whiting was linked to a 16% lower risk of confirmed disability worsening compared with seldom eating lean fish. Eating oily fish — herring, mackerel, tuna, salmon, and trout — each week was linked to a 19% lower risk.
Confirmed disability worsening was defined as an increase in the EDSS score confirmed in a follow-up medical visit at least six months later.
A fish intake frequency score that captured the broader pattern of lean and oily fish also showed that patients with the highest fish intake had a 34% lower risk of confirmed disability worsening than those who never or rarely ate fish. They also had a 45% lower risk of reaching an EDSS score of 3 (moderate disability) and a 43% lower risk of reaching an EDSS score of 4 (significant disability).
Increasing fish consumption after an MS diagnosis
In 2021, 1,719 patients completed a follow-up questionnaire. Based on their answers, the researchers found that 288 patients increased their fish consumption after being diagnosed and 124 decreased their fish intake.
The benefits of eating fish were greater among those who continued to eat fish regularly. But increasing fish intake could still have benefits in confirmed disability progression over the long term. For example, those who increased their consumption from the lowest scores of 2-3 to the highest scores of 5-6 in the five years after their diagnosis had a 20% lower risk of disability progression than those who continued with low fish consumption.
The effects were similar after weighing other factors that may influence disability progression, including physical activity, weight, smoking, alcohol intake, and sun exposure. They also remained similar when adjusted for vitamin D levels.
“Our findings suggest that higher fish consumption is associated with a reduced risk of disability progression in MS, likely due to the anti-inflammatory and neuroprotective properties of nutrients found in fish,” wrote the researchers, who said more studies are needed to validate the results and “investigate the underlying biological mechanisms.” Future studies could also help determine if adding more lean and oily fish to the diet should become part of MS treatment plans.
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