Cover Story: A Closer Look at Diet and MS
By Tom Garry
Reviewed by Barry A. Hendin, MD
In our last issue of The Motivator, our cover story focused on the importance of diet and nutrition in MS. Early research into the effects of diet on MS and dietary recommendations for good general health were featured. However, while a healthy diet rich in fruits and vegetables is recommended for individuals with MS, no specific diet has been proven to be effective for those with MS and more studies are needed. Please note that MSAA does not recommend or endorse any particular diet for the treatment of MS.
In this current cover story of The Motivator, we look more closely at the different types of diets that some believe could be of value to individuals with MS. We also examine the challenges of conducting research into diet and MS. Despite these challenges, several studies have been completed. Results from six of these trials are featured later in this article.
As noted in our previous issue, we caution readers not to make any changes to their diet without first consulting a medical professional. The information provided in this article should not be considered as medical advice. We recognize that individuals have their own specific requirements and preferences in terms of diet, and we hope that the details provided can be of assistance in customizing a diet that not only promotes good health for each individual, but will also provide enjoyment and a better quality of life.
Part One: An Overview of Common Diet Plans
Advocates of various eating plans and researchers assessing those plans tend to agree on two things:
(1) Avoid processed foods as much as possible – these include meats that may be cured or smoked, canned foods and foods with colors or preservatives, as well as food and drinks containing highly refined ingredients with excess amounts of sugar, white flour, and/or salt.
(2) Eat plenty of fruits and vegetables – although some diet plans carry important caveats about which types of vegetables to eat; additionally, some individuals may need to limit the amount of natural sugar they take in through fruits.
When looking at different dietary options, experts say, it is valuable to talk with your MS clinician and/or primary care provider about how well a particular diet is suited to your overall health needs. It’s also important to think about how easy or difficult a particular diet is to follow over the long term. And finally, beware of fads, extreme diets, and diets making claims that cannot be supported by study results.
You do not have to follow a specific diet in order to practice healthy eating. For those interested in adopting a diet, a number of common approaches are available. Please note that the diets to follow are not listed in any particular order.
Vegetarian or Vegan Diets
Among the oldest dietary practices in the world, vegetarianism has been embraced by millions of people for ethical, religious, cultural, or health reasons, while vegan diets are somewhat newer and less widely adopted. Both diets have demonstrated their health benefits but can require a thoughtful approach to ensuring adequate intake of various nutrients.
Definitions vary, but as a general rule, vegetarians do not eat meat, poultry, game or fish, including shellfish, while vegans not only avoid those items, but also do not eat any other food products that come from animals, such as eggs, milk, and butter. Fruits and vegetables are a large part of these diets, which include soy, beans, and legumes.
Mediterranean Diet
This eating plan emphasizes plant-based foods, including vegetables, fruits, whole grains, beans and other legumes, nuts, herbs, and olive oil. Fish is also a key component. Small amounts of poultry, eggs and dairy are other sources of animal protein, while red meat is limited. Moderate consumption of wine with meals is allowed.
Interest in the Mediterranean diet grew after epidemiologists noted a lower incidence of chronic diseases, such as hypertension, diabetes, and coronary artery disease, in people in southern Italy, Greece, and other areas where people followed this approach to eating. Several studies have shown benefits in terms of cardiovascular health, and it has become a major focus of research into the impact of diet on MS.
DASH Diet
This eating plan was developed almost 30 years ago to help reduce high blood pressure (DASH stands for “Dietary Approaches to Stop Hypertension”).
Like the Mediterranean diet, the DASH plan calls for people to center their diet on vegetables, fruits, whole grains, fish, poultry, beans, and nuts. It also entails reduced consumption of red meat, sodium, and foods and drinks with added sugars.
MIND Diet
This approach is the offspring of the union of the Mediterranean diet and the DASH diet: the Mediterranean-DASH diet Intervention for Neurodegenerative Delay, or “MIND” for short.
Developed in 2015 by researchers at Rush University Medical Center in Chicago and the Harvard TH Chan School of Public Health in Boston, this eating plan focuses on preserving the health of the aging brain. Because of the neurodegenerative component of MS, many have expressed interest in this diet, which emphasizes eating the vegetables, fruits, nuts, whole grains, and other items in its “parent” diets (the Mediterranean and DASH diets), while significantly limiting red meat, fried foods, sweets and
pastries, and butter.
The SWANK Diet
The first eating plan developed specifically for people with MS, this low-fat diet was developed by neurologist Roy Laver Swank, MD, PhD. The diet calls for avoiding processed foods containing saturated fats or hydrogenated oils, limiting saturated fats to 15 grams per day or less, and limiting unsaturated fats to 20 to 50 grams each day.
People are advised to not eat any red meats during their first year on the diet, and to consume only three ounces of red meat per week thereafter. Skinless white-meat poultry and white fish are permitted.
Dairy products generally are limited to those containing 1% or less of butterfat. People are encouraged to eat whole grain breads, rice, and pasta, and as many servings of fruits and vegetables as they wish. They also are encouraged to snack on nuts and seeds. In addition, this diet calls for people to take a multi-vitamin and mineral supplements daily, along with one teaspoon of cod liver oil or its equivalent in capsules.1
The Wahls Protocol Diet
Developed by Terry Wahls, MD, who is a physician, medical researcher, and person living with MS, this approach emphasizes consumption of vegetables (particularly leafy greens), berries and other brightly colored fruits, meat and fish, and omega-3 fatty acids, plus other fat from animals and plants. People following this diet steer clear of sugar; dairy products and eggs; tomatoes, potatoes, and other “nightshade” vegetables; legumes, such as beans; and grains, such as wheat or rice.
Dr. Wahls reports that this diet dramatically improved her health and physical function.2 The WAVES randomized parallel-arm clinical trial assessed the impact of the Wahls diet, as well as the Swank diet, on mood and mental health in people with MS. Please see, “Six Intriguing Studies on Diet and MS,” starting on page 14, for a summary of the findings from this study.
The Wahls protocol is one form of a “paleo” diet. Short for paleolithic, the period of human development that lasted more than two million years until about 10,000 BC, the Paleo diet focused on foods that our distant ancestors ate before modern agricultural and food-processing practices predominated.
Anti-Inflammatory Diets
Inflammation is a double-edged sword that the immune system can wield for good or ill. Under normal conditions, an inflammatory response is the body’s way of protecting itself from infection, trauma, toxins, or other threats. In these circumstances, inflammation is beneficial and sometimes even lifesaving.
In other circumstances, however, the body mounts an inflammatory response when a threat is not present, or settles into a chronic state of low-level inflammation. Anti-inflammatory diets are designed to reduce inappropriate and potentially harmful inflammation. Like the Mediterranean and DASH diets, eating plans focused on reducing inflammation include abundant fruits and vegetables. Minimally refined, high-fiber whole grains, coffee and tea, herbs, and dark chocolate with a high percentage of cocoa solids are also components of these diets, which allow for moderate amounts of beer or wine.
In addition, these diets place an emphasis on monounsaturated fats, such as those found in nuts, seeds, olive oil, and avocados, as well as polyunsaturated omega-3 fats, which are found in salmon, sardines, other fish, and walnuts. By contrast, anti-inflammatory eating plans call for little or no consumption of red meats, soda and other sweetened beverages, fried foods, bacon and other processed meats, and refined carbohydrates, such as pasta and white bread.
Gluten-Free Diets
Gluten is a protein found in some cereal grains, such as wheat, rye, and barley. Roughly 1% of the United States’ population is estimated to have celiac disease, an autoimmune condition in which consuming foods with gluten can cause serious gastro-intestinal problems and, over time, significant systemic effects.3
While avoiding gluten is essential for people with celiac disease, many other people have become interested in adopting a gluten-free diet. This includes some people with MS, who note that both celiac disease and multiple sclerosis are autoimmune disorders and – as is the case with most autoimmune disorders – more common in women than men. However, as Ilana Katz Sand, MD, noted in our earlier cover story on diet and MS, research has not shown gluten to play a role in multiple sclerosis development or course, or to be detrimental to people with MS.
Ketogenic “Keto” Diets
First developed almost 100 years ago in an attempt to reduce seizures in children with epilepsy, these low-carbohydrate, high-fat diets have been evaluated more recently for a role in managing conditions from cancer to Alzheimer’s disease, as well as for weight loss. Carbohydrates provide the body with glucose, the primary energy source for cellular function. By significantly limiting carbohydrates, ketogenic diets prompt the liver to convert a back-up source of energy, ketones, from stored fats.
While there is no one “official” ketone (ketogenic) diet, many of these eating plans recommend deriving 70% to 80% of daily calories from high-fat sources such as red meat, processed meat, butter, and foods that contain unsaturated fats, including avocados, nuts, and oily fish. Keto diets typically limit carbohydrates to no more than 10% of caloric intake.
Like classic ketogenic diets, the Atkins diet was developed by cardiologist Robert C. Atkins in the 1960s and is based on low-carbohydrate intake. The South Beach diet, developed by cardiologist Arthur Agatson, MD, in 2003, distinguishes complex carbohydrates (“good carbs”) in fruit, vegetables, whole grains, and beans, from the simple or “bad” carbs found in refined white flour, sugar, and baked goods.
Intermittent Fasting and Caloric Restriction
In these eating plans, the focus shifts from what you eat to when you eat (intermittent fasting) and to a very strong emphasis on how much you eat (caloric restriction). However, the intermittent fasting diet may cause some significant health risks.
According to a report from the American Heart Association (AHA) in March 2024, “A study of over 20,000 adults found that those who followed an 8-hour time-restricted eating schedule, a type of intermittent fasting, had a 91% higher risk of death from cardiovascular disease… Compared with a standard schedule of eating across 12-16 hours per day, limiting food intake to less than 8 hours per day was not associated with living longer.”4
While caloric restriction was not included in this recent report, in January 2023, the AHA released this finding, “Eating less overall and fewer large meals may be a more effective weight management strategy than restricting meals to a narrow time window, such as intermittent fasting, according to a study that analyzed the electronic health records of about 550 adults who were followed for six years.”5
Part Two: Six Intriguing Studies on Diet and MS
The breadth, depth, and promise of current research into diet and MS are evident in several studies published or presented this year. As experts note, not all studies are created equal.
Prospective trials that follow people going forward are preferable to retrospective analyses. Randomized, placebo-controlled trials represent the gold standard for evaluating the impact of a diet, medication, or treatment strategy. And, as a rule, the larger the study and the longer it runs, the more reliable its findings.
With those caveats in mind, the following studies highlight the potential for diet to impact cognition, fatigue, mood, sleep, and many other aspects of MS, including risk for developing the disease.
Swank and Wahls Diets and Their Effects on Mood and Mental Health in People with MS
Developed by Roy Swank, MD, PhD, the Swank diet was perhaps the first eating plan designed specifically for people with MS. Among other things, it places an emphasis on fruits, vegetables, non-fat dairy products, and whole-grain cereals, while restricting saturated and unsaturated fats and oils.
More recently, Terry Wahls, MD, developed the Wahls Protocol, a variation on the Paleolithic diet that eliminates consumption of highly processed foods, grains, and dairy, in favor of meat, fish, and plant-based foods, such as fruits and nuts.
The WAVES randomized parallel-arm clinical trial previously showed that both diets were associated with a reduction in fatigue and improvement in quality of life in people with MS. A secondary analysis of that trial explored an association between these diets and depression as well as anxiety.
People with relapsing-remitting MS were observed on their regular diet and then randomly assigned to either the Swank diet or Wahls Protocol. People in both groups also received vitamin B9 and vitamin B12 supplements.6
After 12 weeks and then at 24 weeks, people following both the Swank arm of the trial and the Wahls arm had significant improvements from baseline on the Hamilton Anxiety and Depression Scale and the Mental Health Inventory, two validated measures of mood and mental health.
Intermittent Caloric Restriction and Cognition
A randomized clinical trial involving 42 people with relapsing-remitting MS found that study participants who practiced intermittent calorie restriction (iCR) saw a significant improvement in cognition over 12 weeks compared to those who did not follow any particular dietary plan.7 Please note that iCR is different from “intermittent fasting,” which has been found to carry cardiovascular risks.
Researchers randomized 22 people to iCR and 20 people to the control group. The study’s primary outcome was the relative effect of calorie restriction on blood levels of leptin and adiponectin, two hormones released by adipose (fat) tissue. However, secondary endpoints included measures of cognition, including the Symbol Digit Modality Test, or SDMT.
Thirty-four of the 42 people who started the study completed the 12-week trial, including 17 people in the iCR group and 17 in the unrestricted diet group. In addition to seeing improvements in the hormone levels that were the main focus of the study, people who practiced intermittent calorie restriction showed greater gains on the SDMT over the study period than those eating an unrestricted diet.
Exploring the Impact of a Low-Fat Diet on Fatigue in MS
Twenty people with MS who followed a low-fat diet for 12 weeks had greater improvements on two measures of fatigue than did 19 other people with multiple sclerosis who kept to their regular diets during that period.8
This was the main finding from a recent two-arm, open-label, randomized controlled trial conducted by researchers from the Oregon Health & Science University and the VA Portland Health Care System. People in the low-fat diet group received one to two weeks of nutritional counseling at the start of the study and then strictly followed a low-fat diet for 12 weeks. Their adherence to that eating plan was monitored by a monthly food frequency questionnaire and 24-hour food recall.
At the end of the study, people in the low-fat diet group saw marked improvements in fatigue relative to the control group as measured by the Modified Fatigue Impact Scale and Fatigue Severity Scale. People in the low-fat group also had an average 11% reduction in calories from fat compared to the control group.
Investigators note that their findings, while encouraging, need to be followed up with trials involving more patients and running for a longer period of time.
Ketogenic Diet and Sleep in People with Relapsing MS
Sleep disturbances are common in MS, and can have a significant impact on quality of life. Based on studies showing an association between a ketogenic diet and improved sleep quality in people with epilepsy, a team of researchers decided to investigate whether there was an association between a modified Atkins ketogenic diet and better sleep in MS.9
Forty-five people with relapsing forms of MS enrolled in the study, agreeing to follow a modified Atkins plan for six months. The study participants’ daytime sleepiness – a marker of poor sleep – was assessed at the start and end of the study with the Epworth Sleepiness Scale (ESS) and Sleep Disorders Symptom Checklist-25 (SDS-CL-25).
Thirty-nine of the 45 people completed the study, with full assessment data available on 36 study subjects. Those participants showed improvements in several areas, including reductions in the relative frequency of excessive daytime sleepiness, in their average insomnia score, and in their average obstructive sleep apnea score.
Mediterranean Diet Associated with Improved Cognition in MS
lana Katz Sand, MD, and colleagues from the Corinne Goldsmith Dickinson Center for MS at Mount Sinai and Johns Hopkins University examined the association between following a Mediterranean-style diet and cognition in 563 people with MS.10 The study participants had an average age of 44.2 years. Seventy-one percent were women, and 108 had some degree of cognitive impairment.
The researchers found that higher scores on the Mediterranean diet Adherence Screener (MEDAS), a survey form that measures how closely people follow a Mediterranean-style diet, predicted a 16% lower risk for cognitive impairment compared to those with lower MEDAS scores. In fact, they noted, MEDAS was a better predictor of people’s cognitive-performance scores than other health-related factors, such as body mass index, exercise level, and the presence of high blood pressure, high cholesterol, or diabetes.
Analysis of the results suggested that the cognitive benefits of following a Mediterranean-style diet were higher in people with progressive forms of MS than in those with relapsing disease.
Mediterranean Diet and Reduced Risk of Developing MS
Following a Mediterranean diet is associated with a roughly 40% reduction in risk of developing MS, according to a trio of researchers from the Karolinska Institute in Stockholm, Sweden.11 The researchers arrived at their conclusion by examining the dietary habits of 1,953 people during the five years before those study subjects were diagnosed with multiple sclerosis. They also examined the diets of 3,557 people who served as a control group.
After adjusting for factors including ancestry, smoking, alcohol consumption, body mass index, physical activity, and sun-exposure habits, they found that a Mediterranean diet was associated with a 41% reduction in risk of MS relative to a traditional Western-style diet. That association remained significant even when excluding people who did not drink alcohol and those with a low degree of fish consumption.
In addition, the researchers did not find a significant association between vegan/vegetarian or low glycemic index diets and reduced MS risk.
In Summary
Identifying the diet plan that is best for you, and then working it into your daily life and following it over the long term, can be challenging. Fortunately, you do not have to “go it alone.”
In fact, you should always talk with your primary care provider or neurologist before embarking on a new approach to your diet. In addition, for those with access to a registered dietitian or nutritionist, consulting one of these professionals along with your primary doctor and/or neurologist can provide you with a nutritional plan customized specifically for you.
We hope that our readers will find the details provided in this article to be informative and potentially spark interest in their own dietary regimen. For all communities, not just the MS community, eating in moderation and making informed food choices will result in a host of benefits to both short-term and long-term health outcomes.
References
1. Swank MS Foundation. The Swank Low-Fat Diet for the Treatment of MS. Available at http://www.swankmsdiet.org/the-diet. Accessed August 14, 2023.
2. Wahls, T. My Story. Available at https://terrywahls.com/about/about-terry-wahls.
Accessed March 2024
3. Beyond Celiac. Celiac Disease: Fast Facts. Available at https://www.beyondceliac.org/celiac-disease/facts-and-figures/. Accessed August 16, 2023.
4. American Heart Association, “8-hour time-restricted eating linked to a 91% higher risk of cardiovascular death,” accessed at https://newsroom.heart.org/news/8-hour-time-restricted-eating-linked-to-a-91-higher-risk-of-cardiovascular-death. Press release dated March 18, 2024.
5. American Heart Association, “Reducing total calories may be more effective for weight loss than intermittent fasting,” accessed at https://newsroom.heart.org/news/reducing-total-calories-may-be-more-effective-for-weight-loss-than-intermittent-fasting. Press release dated January 18, 2023.
6. Shemirani F, Titcomb TJ, Saxby SM, et al. Association of mood and mental health with changes in serum methylation markers in relapsing-remitting multiple sclerosis: secondary analysis of the WAVES Trial. Abstract PSY14. Consortium of Multiple Sclerosis Centers (CMSC) Annual Clinical Meeting 2023.
7. Ghezzi L, Tosti V, Cantoni C, et al. Randomized clinical trial of intermittent calorie restriction in people with multiple sclerosis: effects on immunometabolic and cognitive measures. Abstract CE2.2. Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) 2023.
8. Chase E, Lane MA, Srikanth P, et al. Randomized controlled trial of low-fat diet for fatigue in multiple sclerosis. Abstract DMX02. Consortium of Multiple Sclerosis Centers (CMSC) Annual Clinical Meeting 2023.
9. Perlman J, Lehner-Gulotta D, Wetmore E, et al. Ketogenic diet intervention improves sleep in patients with relapsing multiple sclerosis. American Academy of Neurology 2023.
10. Katz Sand I, Fitzgerald K, Sumowski J. Mediterranean Diet is associated with cognition in multiple sclerosis. American Academy of Neurology 2023.
11. Alfredsson L, Olsson T, Hedstrom AK. Inverse association between Mediterranean diet and risk of multiple sclerosis. Abstract P185. Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) 2023.