Scientists used a special type of genetic study to explore whether eating certain foods could affect the risk of developing multiple sclerosis (MS), a disease that affects the nervous system. They looked at 21 different eating habits and found that people with genetic traits linked to eating more oily fish (like salmon and mackerel) had a lower chance of developing MS. While this is promising news, the researchers emphasize this is one study and more research is needed to fully understand how diet and MS are connected.

The Quick Take

  • What they studied: Whether eating oily fish and other foods could change someone’s chances of getting multiple sclerosis, a disease where the immune system damages nerve cells.
  • Who participated: The study used genetic information from people of European ancestry. Researchers didn’t recruit people directly but instead analyzed existing genetic data from large databases to look for patterns.
  • Key finding: People whose genes suggested they ate more oily fish had about 44% lower risk of developing MS compared to those who ate less. This was a statistically significant finding, meaning it’s unlikely to be due to chance.
  • What it means for you: Eating more oily fish like salmon, mackerel, and sardines might help protect against MS, but this is early evidence. You shouldn’t change your diet based on this one study alone—talk to your doctor about what’s best for your health.

The Research Details

This study used a method called Mendelian randomization, which is like a detective tool for genetics. Instead of asking people what they eat and then watching if they get sick (which can be unreliable), researchers used genetic information to figure out who naturally tends to eat more oily fish. They then checked if those same people had different rates of MS. This approach is stronger because genes are randomly inherited and don’t change based on whether someone gets sick, making it harder for other factors to confuse the results.

The researchers gathered genetic data from large public databases that included information from thousands of people of European ancestry. They looked at 21 different eating habits, not just oily fish. They used several different statistical methods to check their findings and make sure the results were solid. They also tested whether other factors might be influencing the results in sneaky ways.

Regular studies that just ask people what they eat can be tricky because people with MS might change their diet after getting sick, or people who eat certain foods might be different in other ways too. By using genetics, this study gets around those problems. Genetic information is like a permanent record of tendencies that was set before anyone got sick, making it a more trustworthy way to find true cause-and-effect relationships.

The study used well-established scientific methods and checked their work multiple ways. They tested whether their results held up under different statistical approaches and looked for hidden factors that might have skewed the results. However, the study only included people of European ancestry, so the findings might not apply to other populations. The researchers also removed some unusual data points before analyzing, which is standard practice but means the final numbers are based on a slightly smaller group.

What the Results Show

The main finding was that people whose genetics indicated they ate more oily fish had significantly lower MS risk. Specifically, the risk was reduced by about 44% (the study reported an odds ratio of 0.557, which means the odds were about 56% of what they would be otherwise). This difference was statistically significant, with a p-value of 0.013, meaning there’s only about a 1.3% chance this result happened by random luck.

When the researchers tested this finding using different statistical methods, the result held up consistently. This consistency across multiple approaches suggests the finding is probably real and not a statistical fluke. The researchers also specifically looked for hidden factors that might have caused confusion and didn’t find evidence of them.

The study examined 20 other dietary habits besides oily fish—things like eating red meat, processed foods, fruits, vegetables, and dairy products. None of these other foods showed a clear connection to MS risk. This suggests that oily fish might be special in some way, possibly because of its unique nutrients like omega-3 fatty acids, which are known to reduce inflammation in the body.

Earlier studies that simply asked people about their eating habits suggested that diet might affect MS risk, but those studies couldn’t prove cause-and-effect. This genetic study provides stronger evidence for a real connection. The finding about oily fish makes biological sense because oily fish contains omega-3 fatty acids, which scientists know can calm down immune system inflammation—and MS involves too much immune system activity attacking nerve cells.

This study only included people of European ancestry, so we don’t know if the same benefits apply to other ethnic groups. The study used genetic data rather than actual eating records, so it’s measuring genetic tendency to eat oily fish rather than confirmed actual eating. The sample size for this particular finding wasn’t huge, so larger studies are needed to confirm the result. Additionally, the study is observational based on genetic patterns, not a controlled experiment where some people eat more fish and others don’t.

The Bottom Line

Based on this one study, we can say there’s suggestive evidence that eating more oily fish might help reduce MS risk. However, this is early-stage evidence (confidence level: moderate). General health guidelines already recommend eating oily fish 2-3 times per week for heart and brain health, so this finding aligns with existing advice. Don’t make major diet changes based solely on this study—consult with your healthcare provider about what’s right for you.

This finding is most relevant to people of European ancestry concerned about MS risk, and to people already diagnosed with MS who want to manage their condition. People with fish allergies or those who follow certain diets shouldn’t feel pressured to eat fish. If you have MS or a family history of MS, this gives you one more reason to consider including oily fish in your diet, but it’s not a treatment or cure.

If you start eating more oily fish, you wouldn’t expect to see dramatic changes quickly. The protective effect suggested by this study likely builds up over months and years of consistent eating habits. Think of it as one piece of a larger lifestyle puzzle rather than a quick fix.

Want to Apply This Research?

  • Track weekly oily fish servings (salmon, mackerel, sardines, trout, herring) with a goal of 2-3 servings per week. Log the type of fish and portion size to build awareness of intake patterns.
  • Set a weekly reminder to plan one meal with oily fish. Start by trying one new oily fish recipe this week, then gradually build it into your regular meal rotation. Use the app to find and save oily fish recipes you enjoy.
  • Create a monthly chart showing oily fish servings consumed. Track any changes in energy levels or inflammation markers (if you have MS) over 3-6 months. Use the app to identify patterns between fish intake and how you feel.

This research suggests a possible association between oily fish consumption and reduced MS risk but does not prove cause-and-effect. This study should not be used as a substitute for professional medical advice, diagnosis, or treatment. If you have multiple sclerosis or are concerned about MS risk, consult with your healthcare provider or neurologist before making significant dietary changes. This finding applies specifically to people of European ancestry and may not generalize to other populations. Oily fish consumption is not a treatment for MS and should be considered as one part of an overall healthy lifestyle alongside medical treatment.