Researchers studied over 1,500 people from the UK to understand how diet affects multiple sclerosis (MS), a disease that damages the nervous system. They found that people who regularly ate oily fish like salmon and sardines, and ate more whole grain bread, had a lower chance of developing MS. The study also discovered that vitamin D and certain immune cells in the blood may explain why fish is protective. While this research is promising, it shows a connection rather than proof that diet causes the difference, so more research is needed before making major dietary changes.

The Quick Take

  • What they studied: Whether eating certain foods—especially fish and bread—affects the chances of developing multiple sclerosis, a disease where the immune system attacks nerve cells.
  • Who participated: 1,515 people from the UK Biobank database: 303 people who had been diagnosed with MS and 1,212 similar people without MS (matched by age and sex) for comparison.
  • Key finding: People who regularly ate oily fish had notably lower MS risk. Those who ate more whole grain bread weekly also showed reduced risk. The protective effect appeared to work partly through vitamin D and immune cells called neutrophils.
  • What it means for you: Adding oily fish and whole grain bread to your diet may help lower MS risk, though this research shows a connection, not definite cause-and-effect. If you have MS risk factors or family history, discuss dietary changes with your doctor before making major shifts.

The Research Details

This study used a ’nested case-control’ design, which is like a detective story. Researchers started with a large database of people (UK Biobank) and identified those who developed MS over time. Then they compared their eating habits to similar people who didn’t develop MS. This method is efficient because researchers don’t have to wait years for disease to develop—they look back at what people already ate. The study also used a special genetic analysis called Mendelian randomization, which examines whether genetic variations linked to eating certain foods are also linked to MS risk. This genetic approach helps rule out some confusing factors that might make the results misleading.

Case-control studies are valuable because they can identify patterns in what people ate before getting sick, which helps us understand potential protective or harmful foods. The genetic analysis strengthens the findings by showing that the connection isn’t just coincidence—there’s a biological reason why these foods might matter. This combination of approaches gives researchers more confidence in the results.

The study’s strengths include a large sample size (1,515 people), careful matching of control participants to MS cases, and use of genetic analysis to verify findings. The study was published in a peer-reviewed nutrition journal. However, the research relied on people remembering what they ate, which can be inaccurate. The study shows associations (connections) rather than proof that diet causes the difference. Results may not apply equally to all populations since participants were from the UK.

What the Results Show

The main discovery was that regular consumption of oily fish—such as salmon, mackerel, and sardines—was associated with significantly lower MS risk. People who ate more whole grain or wholemeal bread each week also showed reduced risk. These associations remained strong even when researchers looked at specific groups of people (different ages, sexes, and body weights), suggesting the findings are fairly consistent. The genetic analysis supported these findings, showing that genetic factors promoting fish and cereal consumption were linked to lower MS risk. This dual approach—looking at actual eating habits and genetic patterns—makes the findings more credible.

The research identified two biological pathways that may explain why fish is protective: vitamin D levels and neutrophil count (a type of white blood cell). Both of these factors appeared to partially explain the protective effect of eating oily fish. This suggests that fish may work through multiple mechanisms in the body, not just one. The study found these mediating effects were independent, meaning each contributes separately to the protection.

Previous research has suggested that vitamin D deficiency increases MS risk, and this study supports that connection by showing fish—a source of vitamin D—may be protective. The findings align with growing evidence that diet influences autoimmune diseases like MS. However, most prior studies focused on single nutrients rather than whole foods, so this research adds value by examining actual eating patterns. The genetic analysis approach is relatively newer in nutrition research and provides additional evidence beyond traditional dietary studies.

The study relied on participants remembering what they ate, which can be inaccurate and biased. The research shows associations (connections) but cannot prove that eating fish causes lower MS risk—other factors could explain the relationship. The study population was from the UK, so results may not apply equally to other ethnic groups or geographic regions. The sample size, while reasonable, was relatively modest for detecting effects in subgroups. The study couldn’t account for all possible confounding factors that might influence both diet and MS risk.

The Bottom Line

Based on this research, increasing oily fish intake (2-3 servings weekly) and choosing whole grain bread over refined bread appears to be a reasonable dietary approach for MS risk reduction. These recommendations align with general heart-healthy eating advice, so they have multiple potential benefits. However, this evidence is moderate strength—it suggests benefit but isn’t definitive proof. Anyone with MS, family history of MS, or concerns about neurological health should discuss dietary changes with their healthcare provider before making significant shifts.

This research is most relevant for people with family history of MS, those concerned about neurological health, and anyone interested in disease prevention through diet. People already diagnosed with MS may also benefit from these dietary patterns. The findings may be less directly applicable to people in regions where oily fish is unavailable or culturally uncommon, though the principles about whole grains remain relevant. People with fish allergies or specific dietary restrictions should work with a nutritionist to find alternative sources of omega-3 fatty acids and vitamin D.

Dietary changes typically take weeks to months to show measurable effects on blood markers like vitamin D levels. MS itself develops over years, so any protective benefit from dietary changes would likely accumulate over time. You might notice improved energy or digestion within weeks, but neurological benefits would take longer to assess. Consistency matters more than perfection—regular consumption of these foods is more important than occasional eating.

Want to Apply This Research?

  • Track weekly oily fish servings (salmon, mackerel, sardines, herring) and daily bread type (whole grain vs. refined). Set a goal of 2-3 fish servings and 50%+ whole grain bread consumption weekly. Monitor vitamin D levels through blood tests every 3-6 months if available.
  • Replace one refined bread serving daily with whole grain bread. Add one oily fish meal to your weekly menu. Use the app to log these foods and set reminders for shopping or meal planning. Create a simple weekly meal plan featuring fish on specific days to build consistency.
  • Track fish and bread intake weekly using the app’s food logging feature. Set monthly check-ins to assess consistency and adjust portions. If possible, track vitamin D levels through healthcare provider testing every 3-6 months. Monitor energy levels and general wellness as secondary indicators of dietary impact.

This research shows associations between diet and MS risk but does not prove that dietary changes will prevent or treat multiple sclerosis. Multiple sclerosis is a serious medical condition requiring professional medical care. Do not use this information to replace medical advice from your healthcare provider. If you have MS, family history of MS, or are concerned about neurological health, consult with your doctor or a registered dietitian before making significant dietary changes. This study was conducted in a UK population and may not apply equally to all groups. Individual results vary based on genetics, overall health, and other lifestyle factors.