Study shows eating fish can reduce MS progression

A new study has shown that diets which are high in fish and fish oils may have a role to play in slowing MS progression. 

A team of researchers investigated the influence of fish consumption on disability progression in MS. They showed that people that ate fish regularly experienced reduced MS progression. This result may be due to the nutrients that are found in lean and oily fish, such as taurine, omega-3 and omega-6 fatty acids. These have antioxidative and anti-inflammatory properties.

Researchers in Sweden recruited over 2700 people newly diagnosed with MS between 2005 and 2016 for this study. They used a standardised questionnaire and blood samples to collect data on participant's MS and the amount of fish in their diet. The EDSS (Expanded Disability Status Scale) was used to assess disability.

The study team also asked about environmental exposures and lifestyle habits. These included other aspects of diet, alcohol consumption, exercise, sun exposure and vitamin D. They were careful to account for other factors that could have affected the results. These included age at diagnosis, obesity, ancestry, MS duration and type, and whether the study subjects were taking any disease modifying drugs.

In the questionnaire, participants scored how often they ate fish and the researchers converted that into an exposure frequency score. Fish species with a fat content of more than 3% were defined as oily fish. This included herring, mackerel, tuna, salmon, and trout. Lean fish were defined as species with a fat content of less than 3%, such as cod, pollock, haddock, and whiting.

All participants were tracked using the Swedish MS Registry. 1971 participants took a follow-up questionnaire in 2021 to see what had changed since the time of diagnosis. 

Having high fish consumption at the time of diagnosis was associated with a reduced risk of confirmed disability worsening at the time of the follow-up questionnaire. Confirmed disability worsening is an increase in the EDSS score of at least 1 point from baseline, sustained between two further check-ups, at least six months apart.

This association remained consistent after adjusting for lifestyle factors. There was no measurable difference between lean and oily fish. The protective effects of fish consumption were more pronounced among people with MS who ate fish regularly.

The findings suggest that higher fish consumption is associated with more favourable MS disability progression. Further research is needed, but this does support a role for diet in managing MS progression.

This was a nationwide population-based study where researchers recruited 2719 newly diagnosed patients from hospitals and clinics across Sweden. All participants were registered on the Swedish MS registry over fifteen years between 2005 and 2015. The large sample size means we can be more confident in the results.

Previous studies have shown a link between eating fish and fatty acids, and lower levels of disability in MS. However, few have explored the link between fish in the diet and disability progression. This study followed people over a long period of time which adds to the credibility of the results. 

Increasing the amount of fish and fish oils that you eat is likely to be safe. However, you may wish to discuss your diet with a dietitian or other health professional if you plan to make major changes.

If you are interested in reading about research into diet and MS, you may enjoy these articles:

• Can diet affect the course of your MS?
• Is a ketogenic diet good for people with MS?
• Fasting-mimicking diet studied as part of a treatment strategy for MS

For more general information on MS, diets and nutrition:

• Diet and MS: Some general principles around eating healthily for MS.
• Diet and MS symptoms: Evidence-based information on how dietary changes can help with MS symptom management.
• Demystifying diet and MS 1: Overcoming MS and the Wahls Protocol: Our podcast team speak to proponents of two diet plans designed for people with MS.
• Demystifying diet and MS 2: What is a healthy MS diet?: Our podcast team talk to NHS dieticians about making a healthy diet accessible.