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Two Diets Reduced Fatigue and Improved Quality of Life in Society-Funded Clinical Trial --With FAQs

July 31, 2021

Researchers from the University of Iowa have published results from a National MS Society-funded, 36-week controlled clinical trial studying the effects of the Swank (low saturated fat diet) and the Wahls elimination (modified Paleolithic) diets on measures of fatigue and other physical and mental health tests in people with relapsing-remitting MS who were experiencing ongoing fatigue.
Both groups showed significant reductions in fatigue, and improvements in quality of life, indicating the benefits of healthy eating for MS.
“It’s encouraging that fatigue was reduced and quality of life improved in both groups,” says Bruce Bebo, PhD, Executive Vice President of Research for the National MS Society. “This well-conducted study shows that a healthy diet is one pathway to restoring function in people with MS.”
  • Research studies on dietary approaches have generally been of inadequate size and design to provide useful information about dietary strategies in MS. This trial took a carefully designed approach to understanding the potential impact of diet on fatigue and other symptoms commonly experienced by people living with MS. Study participants were asked to continue their usual medications during the study, and also to maintain their usual physical activities and stress reduction regimens, unless their healthcare provider recommended changes.
  • Investigators recruited 87 people with relapsing-remitting MS who experience fatigue to enroll in the 36-week clinical trial. Participants followed their usual diet for 12 weeks (“run-in period”) and then were randomly assigned to follow a low saturated fat diet (a diet developed by Roy Swank, MD) or a modified Paleolithic diet (a diet developed by Terry Wahls, MD). The primary outcome measured were impacts of both diets on the Fatigue Severity Scale, a self-reported clinical measure of fatigue. Other scales of fatigue, quality of life, and physical function were also measured.
  • Of the participants, 77 people completed 12 weeks of the diet portion of the study, and 72 completed 24 weeks. Participants generally stuck with both diets well. Fatigue was reduced significantly compared to the run-in period in both groups at 12 weeks, and these improvements were maintained at 24 weeks. Quality of life improved in both groups as well, with the Wahls group improving on both mental and physical scales, and with the Swank group improving more on the physical than the mental scale. Walking endurance did not improve significantly in either group at week 12.
  • More research is needed to determine how diet affects MS symptoms. Research is ongoing to understand and increase the benefits of dietary approaches in MS.
  • Since both diets showed benefit, the authors noted their similarities: both recommend a high intake of fruits, vegetables, and unsaturated fats, and limit intake of highly processed foods. Read more about how to achieve a healthy diet  
“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, by Terry L. Wahls, MD, Linda G. Snetselaar, PhD, and colleagues (University of Iowa) is published in Multiple Sclerosis Journal – Experimental, Translational, Clinical (published online July 31, 2021). This open-access paper can be read by anyone, without the need for a subscription.

Frequently Asked Questions: Results of Society-Funded Clinical Trial of Dietary Approaches to Treating MS Fatigue

Q. What did this clinical trial study?
A. This trial compared the ability of two different dietary approaches to reduce MS-related fatigue in people diagnosed with relapsing-remitting MS. Participants were randomly assigned to follow a low saturated fat diet (Swank diet) or a modified Paleolithic diet (Wahls diet), along with specific nutritional supplements, and kept careful food diaries. Their health and activities, particularly physical activity level, were extensively monitored before and during the study. The trial lasted 36 weeks.
Q. What is the low saturated fat (Swank) diet?
A. The Swank diet, developed by the late Dr. Roy Swank, limits intake of saturated and unsaturated fats and oils, eliminates processed foods containing saturated fats, eliminates red meat for the first year, and includes eating fruits and vegetables, nonfat dairy products as well as whole grain cereals and pastas.
Q. What is the modified Paleolithic (Wahls elimination) diet?
A. The paleolithic diet involves eating natural foods while avoiding highly processed food, especially high carbohydrate foods that significantly raise blood sugar; and also emphasizes the intake of meats, fish, and plant-based foods (fruits, roots, and nuts). This diet also eliminates foods to which some individuals may be sensitive, including grains, dairy, legumes (including soy), eggs, and a temporary removal of nightshade vegetables (tomatoes, potatoes, eggplant and peppers), but continues to stress a high intake of vegetables.
Q. What were the results?
A. Both diets resulted in significant reductions in fatigue, and improvements in mental and physical quality of life, adding to the evidence of the benefits of healthy eating for people with MS. More research is needed to learn more about how diet improves MS symptoms.
Q. What diet is recommended for people with MS?
A. Although there’s no proven “MS diet,” what and how you eat can make a difference in your energy level, bladder and bowel function, and overall health. Many MS specialists recommend that people with MS adhere to the same low-fat, high-fiber diet recommendations of the American Heart Association and the American Cancer Society for the general population.
Q. Besides fatigue, what other factors were tracked during the trial?
A. Participants were monitored to track their physical activity, nutritional status, mobility, cognition, and mood. Participants were also monitored for potential side effects.
Q. Are there any potential side effects or risks associated with these diets?
A. Yes. For some, eating a restrictive diet may lead to vitamin or mineral deficiencies, which may impact overall health.
The Paleolithic diet theoretically may result in deficiencies in folate, thiamine, and vitamin B6 (due to reduced intake of cereals), calcium and vitamin D (due to lack of dairy intake) and insufficient caloric intake without appropriate nutritional advice. Although no definite deficiencies would be expected to develop from the Swank diet, a recent study showed that people following this diet were consuming less than the recommended levels of vitamins A, C, E, and folate. Taking a good-quality multivitamin and drinking calcium fortified orange juice or nut milks (if not consuming dairy) may reduce the risk of vitamin or mineral deficiency.
For these reasons, participants in the clinical trial were given nutritional supplements and carefully monitored for potential side effects. No serious side effects occurred during the 36-week long study. An analysis of the nutritional intake of the study participants will be completed and reported in a future manuscript.
Q. Were study participants on a MS disease-modifying therapy (DMT)?
A. Most were on a disease-modifying therapy. Enrolled participants were asked to continue their usual medications during the study and also to maintain their usual physical activities and stress reduction regimens, unless their physician or physical therapist recommended changes.
Q. Are these results relevant for everyone living with MS?
A. People with others forms of MS or other chronic health conditions may also experience improved energy and quality of life from adopting the Swank or Wahls diets, but this study did not investigate that question. We do not know how helpful these diets are for reducing fatigue in other forms of MS. This trial was designed to recruit adults with relapsing MS who were experiencing moderate to severe fatigue. Like most controlled trials, the study population does not fully reflect the diversity of the general MS population, since individuals were excluded if they were not able to walk 25 feet with or without a cane, were pregnant or planning to be pregnant, were gluten intolerant, had low body weight, had other diagnosed conditions, or were on insulin or other medications. In addition, because the study required in-person visits, recruitment was limited to people within a 500-mile radius of Iowa City, Iowa. This is likely one reason that there was little racial or ethnic diversity among participants, who were mostly white. Do work with your healthcare team if you are interested in adopting the Swank or Wahls diet or any of the other dietary patterns as part of your personal Wellness Plan.
Q. Is there any reason why I shouldn’t try one of these diets?
A. Unless you have an allergy or medical condition that would prohibit any of the foods suggested for these diets, there’s no reason not to try either one or both diets. However, it is a good idea to check with your healthcare provider before undertaking any major change in your dietary habits so they can monitor any changes. Also, be sure to get the full details about these diets and their recommended nutritional supplements so that you get the nutrition you need while you are trying one of these approaches.
Q. I have progressive MS. Why didn’t the trial include people with progressive MS?
A. The decision to include only individuals with relapsing-remitting MS was made after careful consideration. One reason is that many studies have difficulty recruiting enough participants, and since there are more people diagnosed with relapsing-remitting MS than who have specific forms of progressive MS, the study was more likely to recruit an adequate number of participants. Another reason is that including both relapsing-remitting and progressive participants would require recruitment of many more people, since the results would have to be analyzed to understand the possible differences of those with relapsing versus those diagnosed with progressive participants. This would raise the cost of the study beyond what was feasible.
Q. What other dietary approaches are being tested in MS?
A. The National MS Society is supporting several clinical trials including one exploring the impacts of intermittent calorie restriction. Other studies include investigating the impact of dietary components such as salt and types of foods on immune function, gut microbiome, and MS disease activity. 
Q. Why does the National MS Society invest research money in diet studies?
A. We pursue all promising paths, while focusing on priority areas including progressive MS, nervous system repair, gene/environmental risk factors and wellness and lifestyle. Wellness – and the strategies needed to achieve it – is a high priority for people living with MS and for National MS Society programs and research.
Q: Why did the Society fund this specific study?
A. For the most part, research studies on dietary approaches have been of inadequate size and design to provide useful information about dietary strategies in MS. This trial takes a carefully designed approach to understanding the potential impact of two widely used MS-related diets on fatigue and potentially other symptoms commonly experienced by people living with MS.

About Multiple Sclerosis

Multiple sclerosis is an unpredictable disease of the central nervous system. Currently there is no cure. Symptoms vary from person to person and may include disabling fatigue, mobility challenges, cognitive changes, and vision issues. An estimated 1 million people live with MS in the United States. Early diagnosis and treatment are critical to minimize disability. Significant progress is being made to achieve a world free of MS.

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