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17 April 2020

When it comes to diet and MS, there’s one thing that we can agree on…

Conflicting advice around MS diets is everywhere - and certain types of evidence, including randomised controlled trials, is challenging to achieve and currently lacking.

If there is one thing that the global MS community (Neurologists included) can agree on, it’s that we can’t agree on which diet is the “best” for managing MS. There are many different strategies, from the original Swank diet to the Wahls’ protocol, the Best Bet diet, Ketogenic diet, numerous fasting regimens and of course one of the steps of our very own OMS program

Some have more evidence than others behind their recommendations, and doctors are generally sceptical of any “MS diet”. I am sure many of us have had that extremely frustrating conversation with our MS teams, where we extoll the virtues and benefits of our commitment to the OMS program, only to be told flatly “there’s no evidence for any of that”. 

Lifestyle changes and MS

Increasingly though, the medical community is starting to recognise that certain elements in our lifestyle can have a very real impact on our MS symptoms and indeed long-term prognosis. These include smoking, vitamin D, physical activity levels, having other uncontrolled medical conditions, and you guessed it – our diet. Before you get too excited, this is often restricted at present to the surrogate markers for the quality of our diet, rather than a specific program, for example, our body mass index (BMI) and levels of cholesterol and other lipids (fats) in our bloodstream.

I do not believe that the majority of health professionals take this stance out of malice, but rather from a slightly misguided sense of protectiveness towards their patient, with perhaps just a dash of occasional arrogance.  

Of course, it is their duty to practice evidence-based medicine, to protect their patients from potentially unsafe or unproven treatments – “first do no harm”. But they often fail to recognise that “evidence” should not simply mean a positive result from a large-scale meta-analysis or systematic review of randomised control trials (RCT), but rather it should be “the conscientious, explicit, and judicious use of CURRENT best evidence in making decisions about the care of individual patients”. It should not be the case that just because an RCT has not been performed in a certain area, that there is “no evidence” to support a particular course of action. 

In my own specialty of Obstetrics and Gynaecology, RCTs are actually relatively rare, due to the obvious ethical restrictions on testing treatments on unborn babies. This does not mean that we Obstetricians are all charlatans however; dishing out untried or unsafe advice, but rather we seek our evidence from the next highest available standard, for example observational and cohort studies.    

Studies into lifestyle-based interventions are also notoriously difficult to study in the randomised controlled trial setting, how do you prescribe “fake meat” or “placebo meditation” for example, would patients adhere to a dietary regimen, could they switch treatments groups without the investigators knowing?!

Modified Mediterranean diet study

But these technical issues shouldn’t mean that we don’t strive to obtain that higher-level evidence, and it is with this in mind that a group of researchers from the United States have published a paper in the journal “Multiple Sclerosis and Related Disorders”. 

The team performed a pilot randomised control trial of a “modified Mediterranean dietary program for MS”.  This was designed to test the feasibility of a larger-scale study, aimed at evaluating how a specific diet might impact MS symptoms and potentially, prognosis.

They enrolled 36 females with MS, aged 18-65, from a single MS Treatment Centre in New York City.  All participants were previously following a Western-style diet and had to agree to randomisation, with the only permissible additional supplement being vitamin D.

Those in the dietary intervention group were “encouraged the intake of fresh vegetables and fruits, nuts, legumes, whole grains, avocados, and use of olive oil in cooking.  It advised against the intake of meat (including red meat as well as poultry), dairy, white grains and processed foods”. Participants were also advised to limit salt intake to 2g/day and also abstain from eating for at least 12 hours per night (ideally from 7 p.m. to 7 a.m.  They were given handouts on grocery shopping, reading food labels, and advice on eating out and travel.  

Does any of this sound strikingly similar to another popular MS dietary intervention?!

Those who were in the non-dietary intervention group were offered participation in educational seminars on MS, with access to a dietitian and information handouts on the “diet” at completion of the study.  The study lasted for 6 months, during which time all participants were regularly assessed by the team to ensure there were no issues, and that they were following the diet correctly.

As the study was aimed at establishing the feasibility of future research, their primary goals related to their ability to recruit to a trial, and on maintaining engagement and adherence to the dietary intervention.

The investigators surpassed their intended recruitment target of 30 people in the allotted time frame and in a single centre.  Engagement in the study was excellent, with 90% attendance rates at monthly follow-up meetings, and 90% self-reported adherence to the diet at 6 months (with anonymous reporting to encourage honesty!).


At the end of the study, all 18 people in the diet group had completed the study, with 16/18 from the control group.  The intervention group lost on average 4.8lbs weight more than the non-intervention group during the study (without specific weight loss advice or intention).

With regard to MS symptoms, the intervention group had a statistically significant reduction in fatigue levels (using NFI-MS scores), and also in terms of the impact of MS symptoms on daily life (using MSIS-29 score).  Using EDSS as a measure of physical disability, there was again a statistically significant decrease in disability trajectory in the intervention group compared to the trajectory of the non-intervention group.

16/18 of the participants in the diet group expressed the view that their general health had improved during the 6 months of the study, and 14/18 felt there had been specific benefits with regard to their MS.  

Of course, there were invariably some limitations of the study.  The sample size was relatively small, there were no male subjects and the follow-up period of 6 months was relatively short in terms of a life-long, chronic illness.  They should also aim to include MRI outcomes in the inevitable larger scale research project, but this initial work certainly lays the important first steps on that path.  

The overall approach of the investigators was admirable, and they should be congratulated on their work.  They deliberately encouraged those involved to view the study as an “overall change in their approach to eating, rather than as a diet”.  They intentionally devised an intervention that was most likely to provide benefit for the participants’ MS, but also proven to benefit their overall health, “because our patients do not have MS in isolation; their overall health is extremely important”.  

They noted that it was much easier to recruit to the study than they had previously thought, debunking the myth that pwMS are not interested in using diet to manage their MS. The acceptability and adherence (90%) was also better than anticipated, and the improvement in MS symptoms over the short 6 month study period was “ highly encouraging”. They conclude that dietary intervention protocols that are “fairly restrictive”, include randomisation and are implemented entirely through education are “feasible to conduct in MS”.

In my opinion, these future studies are not only feasible (the HOLISM and STOP-MS studies have already shown us that), but larger random controlled trials are absolutely essential, if we wish to finally convince the medical and wider MS communities of the massive potential benefits that many of us OMSers have already experienced from relatively straight-forward lifestyle modification.   



  1. Randomized-controlled trial of a modified Mediterranean dietary program for multiple sclerosis: A pilot study; Katz Sand, Ilana et al.; Multiple Sclerosis and Related Disorders; Volume 36, 101403

  2. A survey of dietary characteristics in a large population of people with multiple sclerosis; Fitzgerald, K.C. et al.; Multiple Sclerosis and Related Disorders; 

Volume 22, 12 – 18

  1. Conducting dietary intervention trials in people with multiple sclerosis: Lessons learned and a path forward; Fitzgerald, K.C. et al.; Multiple Sclerosis and Related Disorders; Volume 37, 101478

  2. Lipoprotein markers associated with disability from multiple sclerosis; Gafson, A.R., Thorne, T., McKechnie, C.I.J. et al.; Sci Rep 8, 17026 (2018)

  3.  doi:

  4. Yeh Robert W, Valsdottir Linda R, Yeh Michael W, Shen Changyu, Kramer Daniel B, Strom Jordan B et al. Parachute use to prevent death and major trauma when jumping from aircraft: randomized controlled trial BMJ 2018