Mediterranean diet and associations with the gut microbiota and pediatric-onset multiple sclerosis using trivariate analysis

The interplay between diet and the gut microbiota in multiple sclerosis (MS) is poorly understood. We aimed to assess the interrelationship between diet, the gut microbiota, and MS. We conducted a case-control study including 95 participants (44 pediatric-onset MS cases, 51 unaffected controls) enrolled from the Canadian Pediatric Demyelinating Disease Network study. All had completed a food frequency questionnaire ≤21-years of age, and 59 also provided a stool sample. Here we show that a 1-point increase in a Mediterranean diet score is associated with 37% reduced MS odds (95%CI: 10%–53%). Higher fiber and iron intakes are also associated with reduced MS odds. Diet, not MS, explains inter-individual gut microbiota variation. Several gut microbes abundances are associated with both the Mediterranean diet score and having MS, and these microbes are potential mediators of the protective associations of a healthier diet. Our findings suggest that the potential interaction between diet and the gut microbiota is relevant in MS. Multiple sclerosis (MS) is a disease where the immune system attacks the protective covering of nerve cells in the brain. There may be a relationship between diet and bacteria within the gut and MS, however this is not well understood. We investigated how diet and gut bacteria are linked to MS in young people. We examined the diet and types of bacteria in stool samples from those with and without MS. We found that a diet richer in fiber and Mediterranean foods were less common in those with MS. This dietary pattern was linked to certain differences in the gut bacteria. These findings raise the possibility, but cannot prove, that what we eat may help prevent MS by influencing our gut bacteria. This research opens the door to further studies on how diet can impact MS through our gut bacteria. Mirza et al. assess the relationship between diet, the gut microbiota, and pediatric-onset multiple sclerosis. They observe that a higher Mediterranean diet score and nutrient intakes, such as fiber, are associated with a lower odds of having multiple sclerosis, and that the gut microbiota might mediate this protective relationship.