For people with multiple sclerosis (MS), eating a healthy diet of fruits, vegetables and whole grains may be linked to having less disability and fewer symptoms than people whose diet is less healthy, according to a study published in the December 6, 2017, online issue of Neurology®, the medical journal of the American Academy of Neurology.

"People with MS often ask if there is anything they can do to delay or avoid disability, and many people want to know if their diet can play a role, but there have been few studies investigating this," said study author Kathryn C. Fitzgerald, ScD, of Johns Hopkins School of Medicine in Baltimore, Md., and a member of the American Academy of Neurology. "While this study does not determine whether a healthy lifestyle reduces MS symptoms or whether having severe symptoms makes it harder for people to engage in a healthy lifestyle, it provides evidence for the link between the two."

The study involved 6,989 people with all types of MS who completed questionnaires about their diet as part of the North American Research Committee (NARCOMS) registry. The definition of a healthy diet focused on eating more fruits, vegetables, legumes and whole grains and less sugar from desserts and sweetened beverages and less red meat and processed meat. The participants were divided into five groups based on how healthy their diet was.

Researchers also assessed whether participants had an overall healthy lifestyle, which was defined as having a healthy weight, getting regular physical activity, eating a better than average diet and not smoking.

The participants were also asked whether they had a relapse of MS symptoms or a gradual worsening of symptoms in the past six months and reported their level of disability and how severe their symptoms were in areas such as fatigue, mobility, pain and depression.

People in the group with the healthiest diet were 20 percent less likely to have more severe physical disability than people in the group with the least healthy diet. The results were true even after researchers adjusted for other factors that could affect disability, such as age and how long they had MS. Individuals with the healthiest diets also were also around 20 percent less likely to have more severe depression than individuals with the least healthy diet.

Those with the best diet ate an average of 1.7 servings of whole grains per day, compared to 0.3 servings per day for those with the least healthy diet. For fruits, vegetables, and legumes (not including French fries), the top group had 3.3 servings per day while the bottom group had 1.7 servings per day.

People with an overall healthy lifestyle were nearly 50 percent less likely to have depression, 30 percent less likely to have severe fatigue and more than 40 percent less likely to have pain than people who did not have a healthy lifestyle.

The study also looked at whether people followed a specific diet, including popular diets such as Paleo, weight-loss plans or diets that have been touted in self-help books and websites as beneficial for people with MS, such as the Wahls' diet. The researchers found that overall, past or current use of these diets was associated with modestly reduced risk of increased disability.

Fitzgerald said one limitation of the study is that due to study design, it cannot be known if healthy diets predict changes to MS symptoms in the future. Another limitation was that the participants mostly tended to be older, mainly white and had been diagnosed with MS for an average of nearly 20 years, so the results may not be applicable to everyone with MS.