December 16, 2025 | News | Living with MS MS Research MS Treatments

New research on MS diets

Part 3

Diet has had a long-standing relationship with multiple sclerosis, with nutrition influencing the onset and severity of MS. This dates back to an early observation – and since repeated in numerous studies – that people who eat more fatty fish are less likely to develop MS (Baarnhielm and colleagues. Mult Scler 2014;20:726-732). Food is so important that dietitians call diet “almost another disease-modifying therapy” (Ware-Maloney and colleagues. Mult Scler Relat Disord 2025:102:106613).

There are three main reasons why diet is believed to affect the MS disease process. Some dietary nutrients have direct effects on the brain, preserving nerve function and enhancing neural repair (Lefevre-Arbogast and colleagues. Curr Opin Lipidol 2022;33:25-30).

Secondly, consuming foods that promote inflammation in the body can worsen MS. This more inflammatory environment is also seen with obesity, with studies showing that people who are obese during childhood and adolescence have a higher risk of developing various autoimmune disorders, including MS (Xu and colleagues. Int J Obes (Lond) 2025; epublished December 2, 2025). Inflammation can also be driven by food-induced changes to the gut microbiome, the world of micro-organisms residing in the gastrointestinal tract. These organisms not only digest the food you eat – they also sample foods for presentation to the immune system. (Most immune tissue is found in the gut.) This can increase inflammation in the body and the brain.

Thirdly, nutritional components such as vitamins (e.g. vitamin C, E, A) and minerals (e.g. selenium, zinc, copper) can have anti-oxidant effects, which protect tissues from the damage caused by oxygen (so-called free radicals, which are harmful to cells and to DNA).

Numerous diets have been promoted over the years as beneficial for people with MS. The best-studied is the Mediterranean diet, which emphasizes the consumption of fruits, vegetables, whole grains and healthy fats, and avoids saturated fats and processed foods. Some studies have found that the Mediterranean diet may reduce relapses, disability and fatigue in people with MS (Esposito and colleagues. Mult Scler Relat Disord 2021;47:102636. Katz Sand and colleagues. Mult Scler 2023;29:248-260. Moravejolahkami and colleagues. Int J Food Prop 2020;23:1993-2004). More recent studies have reported improvements in mental health and cognitive function with the Mediterranean diet (Yu and colleagues. J Clin Neurosci 2026:143:111756; epublished November 27, 2025. Abbasi and colleagues. Rev Neurol (Paris) 2024;180:1021-1030).

Nutrition studies were one of the highlights at this year’s European Committee for Treatment and Research in MS (ECTRIMS) meeting and the Mediterranean diet figured prominently. A group in Portugal reported that people who adhered closely to the Mediterranean diet had better scores during cognitive testing (Sacramento and colleagues. ECTRIMS 2025;P1287). A separate study found that people on the Mediterranean diet showed beneficial changes in their gut microbiome, with people reporting that they felt fatigue, depression and anxiety symptoms (Chivite and colleagues. ECTRIMS 2025;P1149). Cognitive function also improved with the MIND diet, which combines the Mediterranean diet with the DASH diet (Rezaeimanesh and colleagues. ECTRIMS 2025;P1101). DASH (Dietary Approaches to Stop Hypertension) also emphasizes fruits, vegetables, whole grains, lean proteins and low-fat dairy. There was also less physical disability among people on the MIND diet.

Researchers have also been investigating the problem of ultra-processed foods. These foods have been defined as anything you could not make from scratch in your kitchen, or any food that does not look like the food it is made from. A new study reported that people with MS who consumed more ultra-processed foods over a five-year period experienced more relapses, more active disease and larger brain lesions on MRI (Dalla Costa and colleagues. ECTRIMS 2025;O046). Similarly, a separate study found that ultra-processed foods were associated with more grey-matter damage in the brain and worse cognitive function (Gu and colleagues. J Nutr Health Aging 2025;29:100644).

A study in Belgium also reported on the hazards of holiday feasting. The main culprits were saturated fats, trans-fats, ultra-processed foods and alcohol – with each contributing its share to the processes of brain inflammation and nerve damage (Guisset and colleagues. ECTRIMS 2025;P1456). The overall conclusion from these studies was that we are what we eat – that better foods result in better outcomes. The food choices we make in this time of New Year resolutions can have a significant impact on MS symptoms and well-being.

Part 1, Part 2

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