MS is a very varied disease. We do not know why some people get a severe form of the disease that progresses quickly, and others experience milder symptoms and a slower progression. People with MS are very keen to know what they can do to affect the course of their disease and their symptoms with diet being a particular area of interest. However, to date there is little scientific evidence of what benefits if any can be expected from specific diets that are often promoted for people with MS.
Several studies have been performed investigating the link between diet and MS symptoms. We have previously reviewed them here. However, many of these studies are small and only look at specific food groups or nutrients.
In a recent large USA study published in the journal Neurology, the researchers looked at the link between diet, disability and symptom severity in people with MS.
For this research, they surveyed 6989 people with MS who were registered with the large patient database, the North American Research Committee on MS (NARCOMS). In this survey the researchers asked questions about a person’s current dietary intake, physical activity, smoking status, body mass index (BMI), and any other previous diets they had tried.
The results showed that those with healthier diets (diets high in fruits, vegetables, legumes, whole grains and low in added sugars and red/processed meats) had around a 20% lower chance of suffering from high disability and severe depression than those with the least healthy diets. Specifically, a higher intake of whole grains and dairy was related to less disability, as was previously or currently trying a weight loss diet.
The survey results suggested that people following a diet designed specifically for people with MS by Dr Terry Wahl’s, had higher levels of disability. However, this link may have emerged because more people with progressive MS started this diet compared to those with relapsing MS. Other MS-specific diets were not linked to any differences in disability or symptoms.
No links with fatigue, pain or cognitive symptoms and diet were found. But, a healthy lifestyle (being physically active, having a BMI of less than 25, and not smoking) was connected to less likelihood of suffering from severe depression, pain, fatigue, and thinking issues. A healthy lifestyle was also associated with lower disability.
The researchers did not find any link between healthy or unhealthy diets and relapse rate or MS symptom worsening.
As this study looks at people’s diet and lifestyle at a particular snapshot in time, and does not follow them over time after a change in diet or lifestyle it is not possible to tell whether the differences in disability and symptoms are due to the lifestyle or whether it is the other way around. It is possible that severe MS symptoms hinder a person’s ability to live a healthier lifestyle.
Further long-term studies are required to confirm these results, such as those being performed through the MS Research Australia-sponsored Australian MS Longitudinal Study (AMSLS). Associate Professor van der Mei is currently collaborating with researchers in Professor George Jelinek’s team, using the robust representative sample of people with MS in the AMSLS, to follow-up some of their similar findings on diet and lifestyle.
The USA National MS Society is also currently funding a clinical trial looking at the effects of the Wahls and Swank Diets on fatigue in people with MS.
It is not known if and how diets can cause changes to MS symptoms. Diet is known to affect gut microbiota and immune status, and further studies are need to investigate the mechanisms by which diet is linked to disability and/or symptom severity.