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Dietary Studies in MS

Clinical Research

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While many different diets have been proposed as a treatment or cure for MS, evidence of effectiveness has been limited. Most proposed diets have not been subjected to rigorous, controlled studies, and the few that have been evaluated have produced mixed results. However, researchers are beginning to make significant connections around diet and MS.

Diets Studied in MS

Before reading the details on the studies below, it may be helpful to read our Guide to Understanding Research Studies so you can better understand the terminology used in diet studies. Also, the definition of each diet can vary slightly from study to study, so the details on each study includes the definition of the diet.

Modified Mediterranean Diet

Study: Sand et al., 2019
Participants: n=36 people with MS, randomly assigned to the modified Mediterranean diet intervention group (n=18) or control group (n=18)
Length: 6 months
Details: The intervention group was instructed to follow a modified Mediterranean diet rich in olive oil, fish, nuts, fruits, vegetables, eliminate meat and dairy, and limit most processed foods and salt. Compared to controls, the dietary intervention group lost more weight and experienced reduced fatigue and disability, and improved quality of life. The strengths of this study were inclusion of a control group, randomization, blinded raters and good adherence. The limitations were relatively small sample size and somewhat short duration.
 
What This Means:
Following a modified Mediterranean diet may lead to weight loss, reduced fatigue, reduced disability, and improved quality of life in people with MS.


Ketogenic Diet

Study: Brenton et al., 2019
Participants: n=20 people with relapsing remitting MS all assigned to the diet intervention with no control group
Length: 6 months
Details: The intervention group was instructed to follow a ketogenic diet limited to <20 grams of carbohydrates per day. The group experienced reductions in weight, fatigue, depression and disability. The strengths of this study were relatively good adherence. The limitations were relatively small sample size, relatively short duration, no control group and no randomization.
 
Study: Choi et al., 2016
Participants: n=60 people with relapsing-remitting MS, where n=20 were assigned to a ketogenic diet, n=20 were assigned to a fasting mimicking diet for 7 days followed by a Mediterranean diet, and n=20 were assigned to the control group
Length: 6 months
Details: The ketogenic diet was defined in this study as an average daily intake of <50g carbohydrates, >160g fat and <100g protein intake daily. Those in the group following the fasting mimicking diet consumed 200-350 calories per day for 7 days followed by a plant-based Mediterranean diet. The control group followed no specified diet. This study demonstrated good safety, no harm, improvement in MS-related quality of life and reduced disability in both intervention groups. Strengths of the study were inclusion of a control group, randomization, and relatively good adherence. Limitations were use of unblinded raters, relatively small sample size and somewhat short duration.
 
What This Means:
Following a ketogenic diet may lead to weight loss; reduced fatigue, depression, and/or disability; and, improved quality of life. The long-term safety of a ketogenic diet has not been firmly established.

 


Caloric Restriction and Intermittent Fasting

Study: Fitzgerald et al., 2018
Participants: n=36 people with relapsing remitting MS, randomly assigned to daily caloric restriction group (n=12) or intermittent caloric restriction group (n=12) or control group (n=12)
Length: 8 weeks
Details: All participants’ daily caloric needs to maintain their weight were determined based on their body mass index (BMI) at the beginning of the study. The daily caloric restriction group was instructed to reduce their daily caloric intake by 22%. The intermittent caloric restriction group was asked to consume 75% fewer calories 2 consecutive days a week and eat 100% of their daily calorie needs the other 5 days. Controls were asked to eat 100% of their daily caloric needs every day. Compared to controls, those in the caloric restriction groups lost more weight and experienced improved emotional wellbeing. The strengths of this study were inclusion of a control group, randomization, and blinded raters. The limitations were relatively small sample size, very short duration, and lower adherence in the intermittent caloric restriction group. There were no significant safety issues reported during the study as a result of the diets.

Study: Cignarella et al., 2018
Participants: n=17 people with relapsing remitting MS enrolled during a relapse and randomly assigned to the intervention (n=8) or control group (n=8)
Length: 15 days
Details: The intermittent fasting group was instructed to reduce their daily caloric intake to less than 500 calories every other day, while the control group ate their usual diet. Controls were asked to eat 100% of their daily caloric needs every day. Compared to controls, those in the caloric restriction group lost more weight, though no specific effects on MS were noted. No safety concerns resulted from the diet. The strengths of this study were inclusion of a control group, randomization, blinded raters and good adherence. The limitations were very small sample size and very short duration. There were no significant safety issues reported in participants during the study.
 
What This Means:
Following a program of caloric restriction or intermittent fasting may help with weight loss and improve emotional wellbeing.


Paleolithic Diet (Wahls Protocol)

Study: Irish et al., 2017
Participants: n=34 people with relapsing remitting MS, randomly assigned to the modified paleolithic diet intervention group (n=17) or control (n=17).
Length: 3 months
Details: The modified Paleolithic diet encourages certain fruits, vegetables and meats and prohibits dairy, eggs and gluten. Compared to controls, the intervention group experienced reduced fatigue and improved MS-related quality of life. The strengths of this study were inclusion of a control group, randomization, and blinded raters. The limitations were small sample size and short duration. Additionally, data from only 8/17 people in the intervention group and 9/17 controls were analyzed due to poor adherence/study completion.
 
Study: Bisht et al., 2015
Participants: n=20 people with progressive MS, all assigned to the dietary intervention.
Length: 12 months
Details: The modified Paleolithic diet encourages certain fruits, vegetables and meats and prohibits dairy, eggs and gluten. This intervention also included supplements, exercise, electrical stimulation of the muscles and stress reduction techniques. Participants reported improved fatigue (11/20) and improved MS-related quality of life. The strengths of this study were blinded raters and good adherence. The limitations were no control group, no randomization, very small sample size and relatively short duration.
 
Study: Bisht et al., 2014
Participants: n=10 people with progressive MS, all assigned to the dietary intervention.
Length: 12 months
Details: The modified Paleolithic diet encourages certain fruits, vegetables and meats and prohibits dairy, eggs and gluten. This intervention also included supplements, exercise, electrical stimulation of the muscles and stress reduction techniques. The majority of participants reported improved fatigue over the course of the study period. The strength of this study was having blinded raters. The limitations were no control group, no randomization, very small sample size, relatively short duration, and adherence issues.
 
What This Means:
Following a modified Paleolithic diet, along with a program including exercise, may improve fatigue.

 


McDougall Diet

Study: Yadav et al., 2016
Participants: n=61 people with relapsing remitting MS, randomly assigned to the McDougall diet intervention group (n=32) or control group (n=29)
Length: 12 months
Details: The intervention group was instructed to follow the McDougall diet, which is a very low-fat, plant-based, vegan diet. All meat, dairy, eggs and oils were excluded from the diet. Compared to controls, the dietary intervention group had reduced fatigue, lost more weight, and improved cholesterol and insulin. There were no differences between groups in MRI measurements, number of MS relapses or disability. The strengths of this study were inclusion of a control group, randomization, blinded raters and good adherence. The limitations were relatively small sample size and somewhat short duration.
 
What This Means:
Following a diet that is plant-based and very low in fat may lead to weight loss, improvement in cholesterol levels, and improvement in fatigue.


Swank Diet

Studies: Swank, 1990; Swank & Goodwin, 2003
Participants: n=144 people with MS, all assigned to follow the diet, later designated as “good” vs. “poor” dieters for group comparison.
Length: up to 50 years
Details: The Swank diet is low-fat, where less than 40 grams per day of unsaturated fats and less than 15 grams per day of saturated fats are consumed. During the course of this study, “good” dieters had lower risk of death and decreased disability. The strengths of the study were relatively large sample size and very long duration. The limitations were no control, randomization and no blinding.  
 
What This Means:
Following a diet that is low in fat, particularly saturated fat, may be associated with decreased risk of premature death and disability over time.

Understanding Clinical Research

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