Diet in Multiple Sclerosis: Nutrition, Vitamin D and the Gut Microbiome
There is currently no single diet proven to stop multiple sclerosis, reduce relapses as reliably as disease-modifying therapy, or prevent disability progression. But that does not mean nutrition is irrelevant.
Diet affects body weight, cardiovascular risk, metabolism, bone health, bowel function, constipation, fatigue and general well-being. Some dietary patterns are studied specifically in MS, while recent research on vitamin D and the gut microbiome has produced important but often mixed results.
What can be said about diet in MS without exaggeration?
The picture is more interesting than it was a few years ago: some randomized trials show improvements in fatigue, quality of life and metabolic measures, but evidence that a specific diet reliably changes long-term MS activity remains insufficient.
There are data for symptoms
Mediterranean, low-fat, modified Paleolithic and several other diets have reduced fatigue and improved quality of life in small studies.
For relapses and progression, the evidence is much weaker
Observational studies sometimes find an association between better diet quality and fewer symptoms or less disability, but causality cannot be established from such data.
General health matters
Obesity, hypertension, dyslipidemia, low physical activity and other vascular risk factors are undesirable in MS as well. Nutrition matters for that reason alone.
What should be considered a reasonable baseline diet in MS?
For most people with MS, a sustainable rather than extreme eating pattern is the most reasonable approach — broadly Mediterranean, with plenty of plant foods, adequate protein, fish, unsaturated fats and minimal ultra-processed foods.
Vegetables and fruit
Different types and colors every day. They provide fiber, potassium, folate, polyphenols, carotenoids and many other phytochemicals.
Whole grains
Oats, buckwheat, whole wheat, brown rice, quinoa, barley and other less processed grains.
Legumes
Lentils, beans, chickpeas, peas and soy foods provide protein, fiber and substrates for intestinal fermentation.
Fish
Especially oily marine fish as a source of protein, omega-3 fatty acids and vitamin D. Fish is useful for general cardiometabolic health, although omega-3 supplements are not disease-modifying therapy.
Unsaturated fats
Olive oil, nuts, seeds, avocado and fish are preferable to an excess of saturated fat.
Adequate protein
Fish, poultry, eggs, legumes, dairy or soy foods help maintain muscle mass, which is especially important when physical activity is reduced.
A diet should be livable for years
If someone can follow a diet for only two weeks, is constantly hungry, loses muscle mass or needs a dozen supplements to compensate for restrictions, it is rarely a good long-term strategy.
What is worth reducing?
Ultra-processed foods
Fast food, much industrial baking, sugary drinks and products with high energy density but low nutritional value.
Excess saturated fat
Large amounts of processed meat, fatty meat products, butter, cream, coconut fat and palm fat.
Excess sugar
Especially liquid calories: sweetened drinks, energy drinks and large amounts of desserts.
Excess alcohol
It can worsen balance, fatigue and sleep, affect the bladder and interact with medications.
Dairy products, salt and gluten
Dairy products
Experimental hypotheses have proposed cross-reactivity between some milk proteins and components of nervous tissue. But there is no convincing clinical evidence that all people with MS should completely eliminate dairy.
If there is no intolerance, allergy or other medical reason, moderate dairy intake is acceptable and may be a convenient source of protein and calcium.
Salt
In experimental models, high salt intake can enhance pro-inflammatory Th17 mechanisms. Human observational findings are inconsistent, and there is no convincing evidence that salt directly increases MS activity.
Excess salt is still undesirable because of blood pressure and cardiovascular risk.
Gluten
In celiac disease a gluten-free diet is mandatory. In confirmed non-celiac gluten sensitivity, the issue is individualized.
For a person with MS without celiac disease, a strict gluten-free diet has no proven disease-modifying effect.
Vitamins, omega-3 and micronutrients: where there is a rationale and where there is only theory
| Nutrient | Why it matters | What to do in practice |
|---|---|---|
| Vitamin B12 | B12 deficiency itself can cause neurological symptoms and macrocytic anemia. | Test when clinically indicated and correct proven deficiency. Supplementation without deficiency does not treat MS. |
| Calcium | Important for bone health, especially with reduced mobility, menopause, osteoporosis and repeated glucocorticoid courses. | Assess total dietary intake, vitamin D status and individual osteoporosis risk. |
| Omega-3 fatty acids | Biologically involved in membrane and inflammatory processes. | Fish and other food sources are useful. High-dose fish oil has no proven effect as disease-modifying therapy. |
| Antioxidants | Oxidative stress is genuinely involved in nervous-tissue injury. | This does not mean that high doses of vitamins A, C or E prevent neurodegeneration. Preference should be given to varied food rather than megadose supplements. |
| Iron | Iron deficiency and anemia can substantially worsen fatigue. | Ferritin and other measures should be checked according to the clinical situation; iron is taken when deficiency is confirmed. |
Vitamin D in MS: the association is clear, the treatment effect is much more complicated
Low 25(OH)D is associated with a higher risk of developing MS and, in many observational studies, with greater disease activity. But this does not automatically mean that the higher the dose of vitamin D, the better established MS is controlled.
VIDAMS: high doses did not provide the expected benefit
In VIDAMS, people with RRMS taking glatiramer acetate received either 5,000 IU/day or 600 IU/day of vitamin D3 for 96 weeks.
The higher dose did not reduce the risk of clinical relapse compared with the lower dose. This became an important argument against routinely using high-dose vitamin D as an additional disease-modifying treatment in established RRMS.
D-Lay MS 2025: an unexpectedly positive result
In D-Lay MS, people with clinically isolated syndrome and low or insufficient vitamin D received 100,000 IU of cholecalciferol every two weeks or placebo for up to 24 months.
Composite disease activity was lower in the vitamin D group: 60.3% versus 74.1%, HR 0.66. The difference was driven mainly by MRI activity. There was no statistically significant difference in clinical relapses.
Why the picture has become even less simple
D-Lay MS suggests that at the earliest stage of disease, high-dose vitamin D may have a biologically meaningful effect. But VIDAMS did not confirm clinical benefit from a high dose as an add-on in established RRMS.
Meta-analyses published in 2025–2026 also differ: some report small reductions in relapses, EDSS or new T2 lesions, while others emphasize that results are inconsistent and depend on study design, duration and dose.
Vitamin D deficiency should be identified and corrected, but vitamin D does not replace disease-modifying therapy, and megadoses should not be prescribed automatically.
Popular special diets in multiple sclerosis
People with MS have searched for nutritional approaches that might influence disease course for many decades. Some concepts appeared long before modern disease-modifying therapies, while others grew from newer ideas about metabolism, immunity and the microbiome.
The main diets are described below in detail — not because they are equally useful, but because these are the ones patients most commonly encounter.
Mediterranean diet
The Mediterranean diet is not a strict list of permitted and forbidden foods, but a durable eating pattern rooted in the traditional cuisines of Mediterranean countries. It is well studied for cardiovascular risk, diabetes and overall mortality, making it especially attractive for people with chronic disease.
- plenty of vegetables, fruit, leafy greens and legumes;
- whole grains and other minimally processed plant foods;
- olive oil as the main added fat;
- regular fish and seafood;
- nuts and seeds;
- moderate amounts of dairy and poultry;
- small amounts of red and processed meat;
- minimal sweetened drinks, trans fats and ultra-processed food.
Systematic reviews and small clinical studies suggest possible improvements in fatigue, quality of life, cognition and some inflammatory or metabolic parameters. A 2024 meta-analysis of clinical trials found a reduction in BMI and a borderline-significant effect on fatigue.
In 2025, additional studies of modified Mediterranean diets also reported reductions in fatigue. However, there is still insufficient evidence that a Mediterranean diet by itself reliably prevents relapses or disability progression.
From a practical standpoint, this is one of the easiest models to sustain because it does not require eliminating entire food groups.
Swank diet
Neurologist Roy Swank began developing this diet in the mid-20th century, based on the hypothesis that saturated fat was related to MS activity.
- very low intake of saturated fat;
- restriction of red meat, especially fatty meat;
- restriction of processed meat and high-fat dairy;
- fish and seafood are encouraged;
- whole grains, vegetables and fruit are included;
- vegetable oils and fish oil are typically added.
The historical Swank cohort was followed for decades and reported impressive outcomes among people who strictly limited saturated fat. But it was not a randomized trial, and the effects of diet, behavior, baseline differences and other factors cannot be separated.
The more recent WAVES trial compared the low-fat Swank diet with a modified Wahls Paleolithic diet in people with RRMS. Both groups showed clinically meaningful reductions in fatigue and improvements in quality of life. The study compared two active diets and did not prove that either changes long-term MS activity.
Wahls Protocol and modified Paleolithic diet
The Wahls Protocol grew from the idea that high nutrient density, large amounts of vegetables and avoidance of potentially “problematic” foods might influence mitochondrial metabolism, immunity and well-being in MS.
- large amounts of vegetables and greens;
- leafy green vegetables;
- colorful vegetables and berries;
- vegetables rich in sulfur-containing compounds;
- meat, fish and other protein foods;
- nuts and seeds;
- elimination or marked restriction of grains;
- elimination of legumes;
- elimination of dairy products;
- restriction of refined sugar and industrially processed food.
Early studies were often small and included not only diet but also exercise, stress management and other interventions, making it difficult to isolate the nutritional effect.
In the WAVES trial, a modified Wahls elimination diet reduced fatigue and improved physical and mental components of quality of life. However, the trial was short and was not designed to prove an effect on relapses or long-term disability.
The restrictions of Paleolithic models matter: removing dairy, grains and legumes can reduce intake of calcium, vitamin D, fiber and some B vitamins if the diet is not carefully planned.
McDougall diet
The McDougall diet is a strict plant-based, very-low-fat approach. The foundation is starchy whole foods, vegetables and fruit.
- meat, fish, poultry, eggs and dairy are excluded;
- vegetable oils and other concentrated fats are sharply limited;
- the diet is based on potatoes, whole grains, legumes, vegetables and fruit;
- the total proportion of fat is very low.
In a one-year RCT with 61 participants, a very-low-fat plant-based diet did not provide significant benefit for MRI, relapses or EDSS.
However, fatigue, body weight, total cholesterol, LDL and insulin improved. This is a useful example of how a diet may help symptoms and metabolic health without being a proven disease-modifying treatment.
With long-term strict vegan eating, vitamin B12, protein, iron, zinc, calcium, iodine and vitamin D require attention.
Ketogenic diet
A ketogenic diet sharply restricts carbohydrates and increases fat intake, shifting the body into nutritional ketosis. Ketone bodies become an important source of energy.
- possible effects on mitochondrial metabolism;
- changes in neuronal energy supply;
- modulation of inflammatory signaling pathways;
- effects on insulin resistance and body weight;
- marked changes in microbiome composition and metabolism.
In a six-month phase II study of 65 people with relapsing MS, the ketogenic diet proved feasible: 83% remained adherent through the end. Body fat decreased, while self-reported fatigue and depression fell by roughly half; quality-of-life measures also improved.
However, there was no parallel control group, so the study does not prove that ketosis itself caused these changes. More recent small studies also suggest a possible reduction in fatigue, but do not answer questions about relapses or progression.
- constipation and low fiber intake;
- unfavorable lipid changes in some people;
- kidney stones in predisposed individuals;
- micronutrient deficiencies if the diet is poorly designed;
- difficulty maintaining it long term.
For these reasons, the ketogenic diet is an interesting research strategy but not a standard eating plan for all people with MS.
Intermittent fasting and calorie restriction
Time-restricted eating, fasting-mimicking approaches and moderate calorie restriction are being studied in MS not only for weight loss. Interest relates to leptin, insulin, autophagy, immune-cell metabolism and the microbiome.
- lower leptin and other pro-inflammatory adipokines;
- improved insulin sensitivity;
- changes in metabolic signaling pathways;
- effects on autophagy and mitochondrial adaptation;
- changes in the gut microbiome and its metabolites.
In a randomized study published in JNNP in 2025, 12 weeks of intermittent calorie restriction in people with RRMS was feasible and was evaluated for metabolic, immunological and clinical outcomes including leptin.
This is a biologically interesting direction, but it is still not possible to say that intermittent fasting modifies MS disease course.
- people with low body weight;
- people with sarcopenia;
- osteoporosis;
- pregnancy and breastfeeding;
- eating disorders;
- certain endocrine diseases and diabetes.
Best Bet Diet
The Best Bet Diet is based on the concept of increased intestinal permeability and possible cross-reactive immune responses between food proteins and myelin components.
- dairy products;
- gluten-containing grains;
- legumes;
- eggs;
- yeast.
Saturated fat, salt, sugar and alcohol are also sharply restricted, while the diet centers on vegetables, fruit, fish, lean meat, nuts and olive oil. Various vitamin and mineral supplements are often recommended.
There are no convincing randomized data showing fewer relapses or slower disability progression. The biological hypothesis is interesting but not clinically proven.
Because the diet excludes many food groups, long-term use requires attention to protein, calcium, vitamin D and B vitamins.
Overcoming MS (OMS)
Overcoming MS is not just a diet but a broader lifestyle program. Its nutrition component is mainly plant-based and low in saturated fat, while allowing fish.
- a predominantly plant-based diet;
- avoidance of red meat and much processed food;
- fish and omega-3 sources;
- restriction of saturated fat;
- physical activity;
- stress management and meditation;
- vitamin D.
Observational studies associate stronger adherence to OMS with better quality of life and less severe symptoms. However, because diet, exercise, stress management and other factors change simultaneously, the effect of the diet alone cannot be isolated.
The gut microbiome and MS: a beautiful hypothesis that has not yet become a treatment
The gut is not simply a tube where food is digested. It contains a vast ecosystem of microorganisms that constantly convert what we eat into molecules capable of interacting with the intestinal barrier, the immune system and, indirectly, the central nervous system.
This is why the microbiome has become one of the most interesting areas of MS research. It has everything that makes a scientific story compelling: bacteria, immune cells, barriers, metabolites, gut-brain signaling and the possibility that diet could influence immunity through a chemical factory inside the intestine.
Short-chain fatty acids
Bacteria ferment dietary fiber and produce acetate, propionate and butyrate. These metabolites may influence Treg, Th17, the intestinal barrier and systemic immune responses.
Tryptophan and other metabolites
Bacterial metabolism affects tryptophan derivatives, bile acids and many other signaling molecules potentially relevant to immune regulation.
Intestinal barrier
Microbiome composition can influence the mucus layer, epithelial tight junctions and interactions between the immune system and microbial antigens.
But there is no single “wrong MS microbiome”
Studies do find differences between people with MS and healthy controls. Frequently discussed organisms include Faecalibacterium prausnitzii, Akkermansia muciniphila, Prevotella and others.
However, results across countries and laboratories do not replicate perfectly. In a 2024 systematic review, most studies of overall microbial diversity did not find a stable relationship with MS activity, disease course or progression.
Commercial microbiome testing therefore cannot currently tell a patient: “this is the bacterium causing your MS” or “this probiotic will change your disease course”.
Propionate: one of the first microbiome metabolites to reach a phase 2b trial
Propionic acid is a short-chain fatty acid normally produced by intestinal bacteria during fermentation of dietary substrates. Earlier open studies suggested that levels may be reduced in people with MS and that supplementation might affect immune regulation.
MADAI trial 2026
In a double-blind, placebo-controlled phase 2b trial, 101 adults with stable MS received propionic acid 500 mg twice daily or placebo for 90 days.
Serum neurofilament light fell by about 18% from baseline in the propionate group, and the between-group difference was statistically significant. There was also a signal toward improvement in motor fatigue.
Why this is not yet standard treatment
The study was short and was not designed to prove a reduction in relapse rate, slower EDSS progression or prevention of progression.
A biomarker change is an interesting biological signal, but it is not equivalent to a proven long-term clinical effect.
Can we “fix the microbiome” in MS today?
Probiotics
A 2026 meta-analysis of six placebo-controlled RCTs with 282 participants found a moderate signal of benefit for fatigue, pain and some inflammatory markers.
There was no significant improvement in EDSS, and strains, doses and treatment duration varied widely.
Prebiotics and dietary fiber
Fiber provides substrate for bacterial production of short-chain fatty acids and fits logically with the idea of supporting a metabolically favorable microbiome.
But no specific product can be guaranteed to create the “right anti-inflammatory microbiome” in an individual patient.
Fecal microbiota transplantation
FMT is actively discussed, but in MS published evidence consists mainly of isolated observations and very small series.
This remains experimental rather than a treatment method outside research programs.
What can be done now, even while the microbiome remains a research topic?
The safest strategy is not to try to “treat a particular bacterium”, but to create a food environment that supports a varied diet and normal bowel function overall.
Diverse plant foods
Vegetables, fruit, legumes, whole grains, nuts and seeds provide the microbiome with a wide range of substrates.
Fiber
Fermentable dietary fiber contributes to the production of short-chain fatty acids.
Minimum unnecessary restriction
Without a medical indication, excluding many plant food groups can reduce dietary diversity and fiber intake.
How to prioritize nutrition in MS
1. Do not replace disease-modifying therapy with diet, vitamin D, probiotics or other nutritional interventions.
2. Use a Mediterranean-style pattern as the baseline: varied, mainly plant-based, with fish, unsaturated fats and adequate protein.
3. If overweight, aim for gradual weight loss without loss of muscle mass.
4. Check vitamin D in the laboratory and correct deficiency, but do not use megadoses automatically.
5. If you want to try a special diet — Wahls, Swank, ketogenic, McDougall, intermittent fasting or another — first define the goal: fatigue, weight loss, metabolic markers or personal preference.
6. The stricter the diet, the more important it is to check that it does not cause deficiency of protein, B12, calcium, iron, vitamin D or fiber.
7. Think of the microbiome as a very promising research field, but not yet as a ready-made instruction for selecting a probiotic or “correct bacterium”.
Frequently asked questions about diet in MS
Which diet is considered best for multiple sclerosis?
Should dairy products be eliminated?
Should gluten be eliminated?
Should high-dose vitamin D be taken?
Is the ketogenic diet useful?
Should probiotics be taken?
Can a microbiome test be used to choose a diet?
Consultation with Dr. Lidiia Prakhova
Nutrition questions are particularly important when a person with MS has vitamin D or B12 deficiency, obesity, dyslipidemia, osteoporosis, severe fatigue, constipation or plans to start a strict special diet.
The goal of consultation is to distinguish useful lifestyle changes from restrictions that have no proven benefit and may cause nutritional deficiencies.
Dr. Lidiia Prakhova
Neurologist, Doctor of Medical Sciences. Main areas of clinical work include neuroimmunology, multiple sclerosis, movement disorders, migraine, spasticity and botulinum toxin therapy.
ORCID: 0000-0002-4776-2999
The information on this page is educational and does not replace an individual medical consultation.
Key scientific references
- Parks NE, Jackson-Tarlton CS, Vacchi L, Merdad R, Johnston BC. Dietary interventions for multiple sclerosis-related outcomes. Cochrane Database of Systematic Reviews. 2020;5:CD004192. doi:10.1002/14651858.CD004192.pub4.
- Wahls TL, Titcomb TJ, Bisht B, et al. Impact of the Swank and Wahls elimination dietary interventions on fatigue and quality of life in relapsing-remitting multiple sclerosis: The WAVES randomized parallel-arm clinical trial. Multiple Sclerosis Journal - Experimental, Translational and Clinical. 2021;7(3):20552173211035399. doi:10.1177/20552173211035399.
- Yadav V, Marracci G, Kim E, et al. Low-fat, plant-based diet in multiple sclerosis: A randomized controlled trial. Multiple Sclerosis and Related Disorders. 2016;9:80–90. doi:10.1016/j.msard.2016.07.001.
- Brenton JN, et al. Phase II study of ketogenic diets in relapsing multiple sclerosis: safety, tolerability and potential clinical benefits. Journal of Neurology, Neurosurgery & Psychiatry. 2022.
- Ghezzi L, Tosti V, Shi L, et al. Randomised controlled trial of intermittent calorie restriction in people with multiple sclerosis. Journal of Neurology, Neurosurgery & Psychiatry. 2025;96(2):158–169. doi:10.1136/jnnp-2024-333465.
- Moravejolahkami AR, Shakibaei M, Sharma M, et al. Effect of Mediterranean diet on body mass index and fatigue severity in patients with multiple sclerosis: A systematic review and meta-analysis of clinical trials. Heliyon. 2024;10(18):e37705. doi:10.1016/j.heliyon.2024.e37705.
- Thouvenot E, Laplaud D, Lebrun-Frenay C, et al. High-Dose Vitamin D in Clinically Isolated Syndrome Typical of Multiple Sclerosis: The D-Lay MS Randomized Clinical Trial. JAMA. 2025;333(16):1413–1422. doi:10.1001/jama.2025.1604.
- Bhargava P, Cassard S, Steele SU, et al. High-dose vitamin D3 supplementation in relapsing-remitting multiple sclerosis: a randomised clinical trial. 2023. PMID:37125397.
- Role of vitamin D as adjuvant therapy on multiple sclerosis: an updated systematic review and meta-analysis of randomized controlled trials. 2025. PMID:40797337.
- Vitamin D for multiple sclerosis as an adjuvant therapy: A network meta-analysis of randomized controlled trials. 2026. PMID:42242131.
- Campagnoli LIM, Marchesi N, Varesi A, et al. New therapeutic avenues in multiple sclerosis: Is there a place for gut microbiota-based treatments? Pharmacological Research. 2024;209:107456. doi:10.1016/j.phrs.2024.107456.
- The multiple sclerosis gut microbiome and disease activity: A systematic review. 2024. PMID:39586156.
- Dominguez-Mozo MI, et al. Short-chain fatty acids in multiple sclerosis: Associated with disability, number of T2 lesions, and inflammatory profile. Annals of Clinical and Translational Neurology. 2025;12(3):478–490. doi:10.1002/acn3.52259.
- Moser T, et al. Propionic acid in multiple sclerosis: a phase 2b, double-blind, randomized placebo-controlled trial. Brain. 2026. doi:10.1093/brain/awag099.
- Blanca-Serrano T, Agredano-Sánchez M, López Gigosos RM, et al. Physical, mental and biochemical effects of probiotics in multiple sclerosis: A systematic review and meta-analysis. Clinical Nutrition. 2026;64:106747. doi:10.1016/j.clnu.2026.106747.
Material updated September 2026.
