New research suggests that a diet high in ultra-processed foods may be associated with increased disease activity for individuals in the early stages of multiple sclerosis. The preliminary study found that for every 10% increase in daily calories from these foods, the risk of experiencing a clinical relapse rose by 12%. These convenience foods, which include items like sodas, packaged snacks, and processed meats, are characterized by industrial formulations and numerous additives, distinguishing them from whole or minimally processed foods.
The findings, presented at the American Academy of Neurology’s 76th Annual Meeting, add to a growing body of evidence linking diet to the management of MS, a chronic inflammatory disease of the central nervous system. Researchers followed a group of newly diagnosed patients and observed a direct correlation between their consumption of ultra-processed items and the likelihood of relapse. However, the study authors emphasize that their results show an association and do not prove causation. The research is considered preliminary until it is published in a peer-reviewed journal.
Decoding the Dietary Link
The study categorized foods using the NOVA classification system, which groups foods by their level of industrial processing rather than their nutrient content. Ultra-processed foods (UPFs) sit at the far end of this spectrum. They are typically made from substances extracted from foods, such as fats, starches, and sugars, and often contain additives like artificial flavors, colors, and emulsifiers. Common examples include instant soups, frozen meals, mass-produced breads, sugary breakfast cereals, and reconstituted meat products.
Scientists are increasingly interested in the health impacts of UPFs due to their potential to promote systemic inflammation. The mechanisms are not fully understood but are thought to involve several pathways. The high content of sugar, unhealthy fats, and salt, combined with a low amount of fiber and essential nutrients, can negatively affect the gut microbiome. This imbalance can lead to increased intestinal permeability, sometimes called “leaky gut,” allowing inflammatory substances to enter the bloodstream. For a disease like multiple sclerosis, which is driven by an abnormal immune response and inflammation, this dietary-induced inflammatory state could theoretically worsen disease activity.
Methods of the Investigation
Tracking Patients and Diets
The research team, led by Dr. Matilde Inglese of the University of Genoa in Italy, recruited 105 individuals who had been recently diagnosed with relapsing-remitting multiple sclerosis (RRMS). RRMS is the most common form of the disease, characterized by periods of new or worsening symptoms, known as relapses, followed by periods of recovery, or remissions. Participants were followed for an average of nine months.
At the start of the study, each participant completed a detailed food frequency questionnaire to document their dietary habits over the previous year. From this data, researchers calculated the proportion of their total daily caloric intake that came from ultra-processed foods. Throughout the study period, participants underwent regular neurological examinations and magnetic resonance imaging (MRI) scans of their brains every six months to monitor for signs of disease activity.
Measuring Disease Activity
Researchers tracked two primary outcomes: clinical relapses and changes on MRI scans. A clinical relapse was defined as the appearance of new MS symptoms or the significant worsening of existing ones lasting for more than 24 hours. MRI scans were used to identify new or enlarging brain lesions, which are areas of damage caused by the immune system attacking the protective myelin sheath around nerve fibers. These lesions are a key biological marker of MS disease activity, even if they do not always produce noticeable symptoms.
Relapse Risk and Processed Foods
The analysis revealed a clear statistical link between UPF consumption and disease activity. On average, ultra-processed foods accounted for 26.5% of the participants’ daily caloric intake. The study found that individuals who experienced a relapse during the follow-up period had a significantly higher average intake of UPFs, at 29.5% of their daily calories, compared to 24.7% for those who remained relapse-free.
During the study, 42 of the 105 participants experienced a clinical relapse. The statistical model showed a dose-dependent relationship, with the risk of relapse increasing in step with UPF consumption. The central finding was that each 10-percentage-point increase in the share of calories from UPFs was associated with a 12% higher risk of having a relapse. Furthermore, 31 participants showed evidence of new or enlarging lesions on their MRI scans, indicating ongoing inflammatory activity in the central nervous system, which was also linked to higher UPF intake.
An Unexpected Finding on Healthy Diets
In addition to examining the role of ultra-processed foods, the researchers also investigated whether adherence to a healthy dietary pattern might offer protection against relapses. They specifically assessed how closely participants followed the Mediterranean diet, a pattern rich in fruits, vegetables, whole grains, legumes, and healthy fats like olive oil. This diet is widely recognized for its anti-inflammatory properties and has been linked to better outcomes in a variety of chronic conditions.
Surprisingly, the study did not find any association between adherence to the Mediterranean diet and the risk of MS relapse or new MRI lesion activity in this particular group of patients. This null result suggests that the relationship between diet and MS may be complex. It could indicate that the harmful effects of specific food components, like those found in UPFs, might play a more significant role in early MS disease activity than the broad, protective effects of an overall healthy diet, though more research is needed to explore this possibility.
Limitations and Scientific Context
The authors are careful to point out several important limitations of their work. First and foremost, the findings are preliminary, having been presented at a scientific conference before undergoing the rigorous peer-review process required for publication in a medical journal. Second, the study is observational and shows a correlation, not a direct cause-and-effect relationship. It is possible that other unmeasured lifestyle or environmental factors associated with high UPF consumption could be responsible for the increased relapse risk.
The study’s design also has inherent constraints. The sample size of 105 participants is relatively small, which can limit the generalizability of the findings to the broader population of people with MS. The follow-up period of nine months is also quite short for a chronic disease that evolves over decades. Finally, the research relied on self-reported dietary information, which is subject to inaccuracies and recall bias. Despite these limitations, the study provides a valuable starting point and highlights a clear target for future, more robust investigations, such as longer-term randomized controlled trials.