Expert Voices: Exploring the connection between vitamin D and MS

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In this installment of our “Expert Voices” series, Multiple Sclerosis News Today asked Kassandra Munger to answer some of your questions about the connection between vitamin D levels and multiple sclerosis (MS).

Munger received her bachelor’s in biology from the University of Rochester in 1997, master’s in epidemiology from the University of Massachusetts Amherst in 2001, and doctor of science in nutritional epidemiology from the Harvard T.H. Chan School of Public Health in 2009, where she is a senior research scientist in the Neuroepidemiology Research Group in the Department of Nutrition.

For 20 years, Munger has worked with large cohorts, including the Nurses’ Health Studies and active-duty U.S. military personnel, to investigate the role of the Epstein-Barr virus and vitamin D, as well as other environmental risk factors such as obesity, in multiple sclerosis. Her research interests also include whether established MS risk factors influence MS progression and whether MS patients with generally healthy lifestyles experience better outcomes. 

Can you summarize findings on how vitamin D connects to MS? 

Kassandra Munger has produced large-cohort studies on the connection between vitamin D levels and multiple sclerosis. (Photo courtesy of Kassandra Munger)

Many studies show that individuals with higher levels of vitamin D — which is measured by blood levels of 25-dihydroxyvitamin D — have a decreased risk of MS and that those who are vitamin D-deficient have an increased risk of MS. Together, these studies suggest that there is a 30%–50% decreased risk of MS with levels higher than 75 nanomoles per liter (nmol/L) and a twofold increased risk among those with levels less than 30 nmol/L. 

Further, studies of vitamin D levels in early life (maternal levels during pregnancy or levels in newborns) have found that low levels of vitamin D predict an increased risk of MS as an adult. In persons with MS, studies suggest that vitamin D may decrease the risk of MS relapses and development of new lesions in persons with MS. 

Has anything in vitamin D research surprised you or has it all fit your expectations?

Early in the research on vitamin D and MS, the association itself was not necessarily expected. Studies in animals had suggested that vitamin D may favorably affect immune response and prevent an MS-like disease (in animals) or greatly reduce the progression and disability associated with the disease. But results from experimental animal studies are not always seen in humans.

There is also remarkable consistency between many studies using different measures of vitamin D — assessing amount of sun exposure, vitamin D blood levels, or eating foods high in vitamin D in different populations worldwide — with nearly all pointing to vitamin D being an important risk factor for MS.

Can stabilizing vitamin D levels help a person already diagnosed with MS, or should healthy levels of vitamin D be thought of only as a potential preventive to MS?

There is evidence that individuals with MS may benefit from having adequate vitamin D levels. Several studies have found that lower vitamin D levels are associated with higher relapse rates and an increase in the number of brain lesions. One limitation in many of these studies is that persons with more active disease may not leave their home as often or get enough sun exposure to maintain vitamin D levels, so the low vitamin D levels may be because of more active disease. There have been a few randomized, controlled clinical trials that gave people with MS varying doses of vitamin D supplements, and they suggest that higher blood levels of vitamin D may reduce the appearance of new brain lesions.

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Are there ideal methods and/or strategies for vitamin D delivery?

There are two ways our bodies get vitamin D. One is from exposure to sun. Sun rays activate a process in the skin that produces vitamin D. The other is through diet. Eating a diet high in vitamin D-rich foods, such as salmon, fortified products, or vitamin D supplements,  will also increase vitamin D levels. Sun exposure is the primary way most people get vitamin D: 10–20 minutes of skin exposure can produce the equivalent of 10,000 IU of vitamin D. Compare that to diet where a serving of salmon has about 400 IU.

With concerns about skin cancer with excessive sun exposure over time, vitamin D supplements have gained in popularity. Over-the-counter supplements provide 1,000 to 2,000 IU of vitamin D. Before taking supplements, it may be useful to have vitamin D levels tested to see if supplementation is needed, and if so, what dose is optimal.

Does vitamin D research indicate needed changes in clinical strategies?

The current evidence is not sufficient to recommend changes in clinical strategies to using vitamin D as a treatment for MS. However, there is a great deal of research showing that vitamin D nutrition may affect the risk of other diseases, such as some cancers and cardiovascular disease, so a whole-health approach to vitamin D testing and supplement use should be considered.

What other research about vitamin D is needed?

Ideally, a randomized clinical trial of vitamin D and prevention of MS would be conducted to determine whether high vitamin D levels can prevent MS. There are many challenges to conducting such a study, however, and it is unlikely to be done. More well-designed clinical trials of vitamin D and MS outcomes are needed to determine whether there may be any therapeutic benefit of vitamin D beyond what current disease-modifying therapies already provide. 

Do you have advice for readers who have MS and are concerned about their vitamin D?

If you have concerns regarding whether your vitamin D levels are good, ask your doctor. They will be able to measure the levels of vitamin D in your blood and then provide guidance on whether you need to take a vitamin D supplement, and if so, what the appropriate dose is for you to keep your vitamin D in the healthy range. 

Expert Voices is a monthly series involving a Q&A with an expert in the MS space about a specific topic. These topics and questions are curated from a survey in which we ask readers what they want to learn more about from experts. 

Multiple Sclerosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.