Researchers followed over 41,000 Swedish people for nearly 18 years to see if eating a Mediterranean diet—lots of vegetables, fruits, fish, and olive oil—could help prevent multiple sclerosis (MS), a disease that affects the nervous system. They found that people who ate more Mediterranean-style foods had a lower chance of developing MS, especially if they didn’t smoke and were under 45 years old. While the connection is promising, the study shows that diet alone isn’t a complete solution, and more research is needed to understand exactly how these foods might protect the brain and nervous system.

The Quick Take

  • What they studied: Whether eating a Mediterranean diet (rich in vegetables, fruits, fish, whole grains, and olive oil) could reduce the chances of developing multiple sclerosis
  • Who participated: 41,428 people in Sweden who were asked about their eating habits in 1997 and then tracked for about 17.6 years to see who developed MS
  • Key finding: People who followed a Mediterranean diet more closely had about 14% lower risk of developing MS. Non-smokers who ate this way had an even bigger benefit—26% lower risk. Younger people (under 45) also saw more protection than older adults
  • What it means for you: Eating more Mediterranean-style foods might help protect against MS, especially if you’re young and don’t smoke. However, this doesn’t mean diet alone prevents MS—it’s one piece of a bigger health puzzle. Talk to your doctor about whether this eating pattern makes sense for you

The Research Details

This was a long-term follow-up study called a cohort study. Researchers started with 41,428 Swedish people and asked them detailed questions about what they ate in 1997 using a food questionnaire. They then tracked these same people for about 17.6 years using Swedish health records to see who developed multiple sclerosis. The researchers created a Mediterranean Diet Score (ranging from 0 to 9) based on how closely each person’s eating habits matched the Mediterranean pattern—higher scores meant eating more Mediterranean foods. They used statistical methods to compare MS risk between people with different diet scores, while accounting for other factors like age, smoking, and exercise.

This study design is valuable because it follows real people over many years in their normal lives, rather than testing them in a lab. This makes the results more realistic and applicable to everyday people. By tracking actual health records instead of relying on people to remember if they got sick, the researchers could accurately identify who actually developed MS. The long follow-up period (17.6 years) also gives enough time for MS to develop, since it’s not a disease that appears overnight.

This study has several strengths: it included a large number of people (over 41,000), followed them for a long time, and used official health records to confirm MS cases rather than relying on memory. The researchers also adjusted their analysis for many other factors that could affect MS risk. However, the study only looked at Swedish people, so results might be different in other populations. Also, people’s diets can change over time, but the study only measured diet once at the beginning. The number of actual MS cases (89) was relatively small compared to the total group, which means the findings need to be confirmed by other studies.

What the Results Show

During the nearly 18-year study, 89 people developed multiple sclerosis out of the 41,428 participants. People who scored higher on the Mediterranean Diet Score had lower MS risk. For every one-point increase in the diet score (out of 9 possible points), the risk of developing MS dropped by 14%. This might sound small, but it adds up—someone with a score of 9 would have significantly lower risk than someone with a score of 0.

When the researchers looked at smokers versus non-smokers separately, they found something interesting: non-smokers who ate Mediterranean-style foods had a much bigger benefit, with 26% lower MS risk. However, smokers didn’t show the same protection, even if they ate well. This suggests that smoking might override the protective benefits of a healthy diet.

Age also mattered. Younger people (age 45 and under) who ate Mediterranean foods had about 23% lower MS risk. But in older adults (over 45), the diet didn’t seem to provide the same protection. This could mean that diet is most protective when you’re younger, or that other factors become more important as people age.

The study found that the protective effect of the Mediterranean diet was strongest in people who combined it with not smoking. This suggests that lifestyle factors work together—eating well is helpful, but avoiding smoking makes the benefit even stronger. The age-related findings also suggest that starting a Mediterranean diet earlier in life might be more beneficial for MS prevention than starting later.

Previous research has shown that Mediterranean diets protect against other brain diseases like Alzheimer’s and Parkinson’s. This study adds to that evidence by suggesting the diet may also help prevent MS, which is a different type of brain disease. However, MS is less common than these other diseases, so there’s been less research on diet and MS specifically. This study is one of the first large, long-term studies to examine this connection in detail.

The study only measured what people ate once, at the beginning in 1997. People’s diets change over time, so the researchers couldn’t track whether people stuck with Mediterranean eating or changed their habits. The study only included Swedish people, so the results might not apply to other countries or ethnic groups with different genetics and food availability. The number of people who actually developed MS (89 cases) was small compared to the total group, which means the findings need to be confirmed by other studies. Also, the researchers couldn’t prove that the diet directly caused the lower MS risk—they only showed that people who ate this way had lower rates of MS. Other unmeasured factors could have played a role.

The Bottom Line

Based on this research, eating a Mediterranean diet appears to be a reasonable choice for overall health and may help reduce MS risk, particularly if you’re under 45 and don’t smoke. The evidence is moderate—it’s promising but not definitive. Focus on eating more vegetables, fruits, whole grains, fish, and olive oil while reducing red meat. However, diet alone is not a proven way to prevent MS. If you have concerns about MS risk or family history of the disease, talk to your doctor about comprehensive prevention strategies

This research is most relevant for younger adults (under 45) who are concerned about MS risk or have family members with MS. Non-smokers may see more benefit than smokers. People interested in brain health and disease prevention in general should also pay attention. However, if you’ve already been diagnosed with MS, talk to your neurologist about whether dietary changes might help manage your condition. This research is not a substitute for medical treatment if you have MS

If you start eating Mediterranean-style foods, you shouldn’t expect immediate changes. MS develops over years or decades, so any protective benefit would also take years to show up. Think of this as a long-term investment in your health rather than a quick fix. You might notice other benefits sooner, like improved energy, better digestion, or improved cholesterol levels, but MS prevention specifically would take years to evaluate

Want to Apply This Research?

  • Track your Mediterranean Diet Score weekly by logging: servings of vegetables (goal: 3+), fruits (goal: 2+), whole grains (goal: 3+), fish (goal: 2-3 times/week), olive oil use (goal: daily), and red meat (goal: limit to 1-2 times/week). Score yourself 0-9 based on adherence and monitor trends over months
  • Start by adding one Mediterranean element to each meal: add olive oil to salads, swap white bread for whole grain, add fish to dinner twice a week, or increase vegetable portions. Use the app to set weekly goals for each food category and get reminders to track them
  • Review your Mediterranean Diet Score monthly to see if you’re improving adherence. Set a goal to increase your score by 1-2 points every 2-3 months. Also track other health markers like energy levels, digestion, and cholesterol if available. Remember that consistency over years matters more than perfection week-to-week

This research suggests a possible connection between Mediterranean diet and lower MS risk, but it does not prove that diet can prevent or cure multiple sclerosis. The study was observational, meaning it shows association but not definitive cause-and-effect. If you have been diagnosed with MS or are concerned about your MS risk, please consult with your neurologist or healthcare provider before making significant dietary changes. This information is for educational purposes and should not replace professional medical advice, diagnosis, or treatment. Individual results may vary based on genetics, overall lifestyle, and other health factors.