The Link Between Obesity and Multiple Sclerosis

Obesity in early life increases your chances for developing multiple sclerosis

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Obesity is a worldwide epidemic, and a leading culprit behind many chronic health conditions (e.g., heart disease and diabetes, among others). Even more, research has found that obesity in childhood and adolescence may contribute to the development of multiple sclerosis (MS)—and this finding is critical, as it implies some control over this notoriously unpredictable neurological disease.

Let's take a look at the research supporting the link between obesity and MS pathogenesis, and perhaps more importantly, what this means for us, our children, and the future of MS.

Two healthcare provider looking at a brain on a monitor

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Research: Obesity Increases Your Risk for Developing MS

The following research studies suggest that obesity in early life increases a person's risk of developing MS.

One Denmark study, which was based on over 300,000 children born between 1930 and 1983, found that people with a childhood body mass index (BMI) in the 95th percentile or higher were 70 percent more likely to develop MS than those with BMIs less than the 85th percentile.

Keep in mind, BMI is a calculation of a person's body fat, based on their height and weight. While not perfect, it's a good estimate of your body size, whether you are underweight (less than 18.5), normal weight (18.5 to 24.9), overweight (25.0 to 29.9), or obese (above 30.0).

BMI is a flawed measure because it does not take into account factors such as body composition, ethnicity, sex, race, and age. Even so, BMI is still widely used in the medical community because it’s an inexpensive and quick way to analyze a person’s potential health status and outcomes.

Moving forward, another very large study in the United States found that women with a body mass index of thirty or higher at age 18 had a more than a two-fold risk of developing MS, as compared to lean women. (Interestingly, this study did not find an association between a large body size in childhood and an increased risk for developing MS).

Finally, a third study in Neurology of nearly 600 children, found that being overweight increases a child's risk for developing pediatric-onset MS. Pediatric multiple sclerosis makes up about 5 percent of all MS diagnoses.

Why Obesity Increases Your MS Risk

Scientists are still scratching their heads as to why obesity in early life (especially adolescence) increases a person's risk for developing MS.

Vitamin D Deficiency

Some experts suspect that vitamin D deficiency may be the mediating culprit.

Vitamin D is often called the "sunshine vitamin" because it's primarily produced by the skin when exposed to the sun's ultraviolet rays.

While it has not all been teased out yet, here are two potential reasons why obesity may predispose to vitamin D deficiency:

  • The skin surface of obese people does not increase in proportion to their weight change—so their skin cannot produce sufficient amounts of vitamin D for their body size
  • Since vitamin D is a fat-soluble vitamin, it may get sequestered or hidden away in fat tissue

Regardless of exactly why obese people are prone to vitamin D deficiency, we know that vitamin D deficiency by itself is associated with MS development in both adults and children.

Vitamin D deficiency may also negatively impact your MS disease activity (i.e., trigger MS relapses), which is why most MS specialists ensure adequate vitamin D levels in their patients.

Obesity-related Inflammation

Moving forward, besides the obesity/vitamin D deficiency cycle, other experts suspect that the release of certain cell signaling proteins (called adipokines) from adipose (fat) tissue in obese individuals may modulate the immune system in such a way that it promotes MS development.

In fact, one such adipokine, called leptin, has been found to be significantly higher in people with MS compared to people without MS. Although, similar to vitamin D, how exactly the obesity/leptin/MS factors are intertwined is still a mystery.

What Does This Mean for Me?

Taking a step back, keep in mind that being obese in early life does not mean that you will definitively develop MS. In fact, it's statistically likely that you will not develop MS. On the same note, just because you were of normal body size in childhood, does not mean you cannot develop MS.

The bottom line here is that a link exists between MS development and obesity but a link does not imply causation; rather, a link indicates that some sort of connection or association exists between these two conditions.

Remember too, besides environmental factors, like obesity and vitamin D deficiency, genetics play an important role in MS pathogenesis. In other words, experts believe that a person must be genetically vulnerable to developing MS and then exposed to an environmental factor or factors that triggers MS onset. Besides obesity and vitamin D deficiency, other potential environmental triggers include infection with the Epstein-Barr virus and exposure to cigarette smoke.

Other Obesity/MS Connections

Besides the fact that being obese in childhood and/or adolescence increases your risk for developing MS, other potential connections include the following:

  • Depression is common in MS and obesity may increase your risk for depression or vice versa (or both)
  • Obesity is linked to numerous physical health problems (e.g., heart disease, sleep apnea, diabetes, and osteoarthritis), which can worsen disability and MS-related symptoms, like fatigue and pain
  • Obesity represents a state of chronic low-grade inflammation, which may influence your MS disease course
  • Steroids (for example, prednisone) which are used to ease MS relapses, can contribute to weight gain, as can being sedentary from having MS

Achieving a Normal Weight

If you or a loved one has MS, you may be worried your child will develop MS (the risk of a child developing MS if a parent has MS is about 3 to 5 percent, versus 0.1 percent in the general population).

Alternatively, maybe you are overweight or obese and desire to get back to normal weight to see if that will help your MS symptoms.

Regardless of the motivation, it's important to obtain and maintain a normal, healthy weight.

Here are a few tips to file away as you embark on a healthy weight plan:

  • Try not to diet or restrict food groups. In the end, this will likely backfire, as you will eventually cave into a craving and then possibly, binge on that food. Instead, focus on moderation.
  • Choose healthy, protein-rich snacks (e.g., peanut butter on whole-grain crackers, a handful of nuts mixed in with dried fruit ("trail mix"), string cheese, or hummus with celery sticks
  • Eat at your kitchen table, not in front of the TV or while talking on the phone, which almost always leads to overeating
  • Talk with your healthcare provider about starting an exercise program, and choose a form of exercise that is enjoyable for you, and thus sustainable, like dancing or taking your dog for long, daily walks.
  • If you use a mobility-assistive device or are limited by your MS-related fatigue, pain, or spasticity, try not to be discouraged. Do what exercise you can, such as performing arm exercises and lifting small weights.
  • Prepare your own meals and avoid buying junk food. If those yummy but unhealthy treats are not in your pantry, you can't go and grab them during a weak moment.

A Word From Verywell

No doubt about it—MS is a devastating neurological disease that tends to strike at the prime of young adulthood, when people are thinking about marriage, children, and future career prospects.

The upside though is that we are learning more and more about MS each day. As more information emerges, lets' soak it in and remain resilient and as healthy as we can.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  • Ascherio A, Munger KL. Weighing Evidence from Mendelian Randomization—Early-Life Obesity as a Casual Factor in Multiple Sclerosis? PLoS Med. 2016 Jun;13(6):e1002054. doi:10.1371/journal.pmed.1002054

  • Drincic AT, Armas LA, Van Diest EE, Heaney RP. Volumetric dilution, rather than sequestration best explains the low vitamin D status of obesity. Obesity (Silver Spring). 2012 Jul;20(7):1444-8.

  • Gianfrancesco MA et al. Evidence for a casual relationship between low vitamin D, high BMI, and pediatric-onset MS. Neurology. 2017 Apr 25;88(17):1623-29. doi:10.1212/WNL.0000000000003849

  • Munger KL, Chitnis T, Ascherio A. Body size and risk of MS in two cohorts of US women. Neurology. 2009 Nov 10;73(19):1543-50. doi:10.1212/WNL.0b013e3181c0d6e0

  • Munger KL. Childhood body mass index and multiple sclerosis risk: a long-term cohort study. Mult Scler. 2013 Sep;19(10):1323-29. doi:10.1177/1352458513483889

  • Xie F, Huang XH, Shen AZ, Li J, Sun YH. Association between circulating leptin levels and multiple sclerosis: a systematic review and meta-analysis.Postgrad Med J. 2018 May;94(1111):278-83. doi:10.1136/postgradmedj-2017-135397.

By Colleen Doherty, MD
 Colleen Doherty, MD, is a board-certified internist living with multiple sclerosis.