Relationship | What Is Vitamin D? | Increasing Vitamin D Levels | Too Much Vitamin D? | Talk to Your Doctor | Support

Vitamins and minerals: They are listed on nearly every nutrition label, including on foods and drinks that claim to be fortified with them. You may have heard that vitamin D, a commonly fortified vitamin, is good for calcium absorption and bone health. But what do vitamin D levels have to do with symptoms or risk of multiple sclerosis (MS)?

The research to date has shown that vitamin D might play a larger role as an environmental factor in MS than previously thought. In this article, we explore the role of vitamin D levels in the risk of MS and how vitamin D levels affect MS symptoms.

The Relationship Between Vitamin D and MS

Low levels of vitamin D have been linked to many autoimmune diseases, including MS. In addition to supporting bone and muscle health, vitamin D levels also play a role in strengthening your immune system and immune cells (like T cells and B cells) — which are abnormal in MS.

Some research suggests vitamin D has a protective effect. For example, studies found that people with higher levels of vitamin D (according to diet or blood measurements) had a 40 percent to 62 percent lower risk of developing MS than people who had lower levels of vitamin D.

Although evidence is mixed, some studies suggest that for people with MS, high-dose vitamin D intake may reduce the severity of disease progression, disease activity, and relapse rate. Higher vitamin D levels during pregnancy may also protect the baby from developing MS.

Along those lines, research has found that in people who had clinically isolated syndrome (early symptoms that suggest MS), low vitamin D levels were correlated with more severe progression of MS.

The connection between low vitamin D levels and MS may also explain why people who live further from the equator — with less sunshine to help the skin produce vitamin D — have a higher prevalence and increased risk of MS compared to people in warmer climates.

What Is Vitamin D and How Is It Made?

Vitamin D comes in two main forms when it enters the body — vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D2 is largely human-made and added to many of the foods we eat. Most of our vitamin D3 intake comes from the ultraviolet rays in sunlight exposure. Sunlight hits the skin, and skin cells use the energy from sunlight to make vitamin D3.

Both forms of vitamin D are then sent to the liver, where the vitamin D precursor is turned into another molecule called 25-hydroxyvitamin D (25OHD). This molecule then goes to the kidney, which processes the 25OHD into a final form of vitamin D (calcitriol). From there, it goes on to do many things we associate with vitamin D, including fostering bone growth, maintaining calcium levels to help avoid osteoporosis, and strengthening the immune system.

Increasing Your Vitamin D Levels

Because vitamin D comes from food and sunlight, getting higher levels generally means consuming more sources of the vitamin and getting more sun exposure.

Few foods are naturally high in vitamin D, but they include fatty fish, eggs, beef, and cod liver oil. Other foods may be fortified with vitamin D, such as milk and some cereals.

Vitamin D supplementation is also an option — more than 14,000 members of MyMSTeam report that they take vitamin D supplements for their health. Supplements containing vitamin D2, vitamin D3, or a combination of both are all available.

Various professional organizations, such as the Institute of Medicine and the Endocrine Society, have indicated optimal vitamin D levels and intake to use as guidance. People with a vitamin D deficiency who need vitamin D supplements should aim to have a blood level higher than 40 nanograms per milliliter.

One option is taking high-dose vitamin D2 — generally 50,000 international units (IUs), once per week. Another option is taking vitamin D3, which is usually taken daily at a dose between 1,000 and 5,000 IUs.

Always talk to your doctor for their medical advice before you begin taking supplements. They can help ensure vitamin D supplementation is safe for you, and they can recommend the right dose and frequency.

Can You Have Too Much Vitamin D?

In short, yes. Having too little vitamin D may be an issue, and you don’t want to have too much, either. The effect of having too much vitamin D is called vitamin D toxicity. Some animal model studies show that vitamin D doses that are too high can worsen MS symptoms and cause complications such as encephalomyelitis.

Vitamin D toxicity can also lead to an overabundance of calcium in your system (a condition called hypercalcemia), which can have serious effects on your body.

Signs and Symptoms of Excess Vitamin D

Vitamin D toxicity, also known as hypervitaminosis D, can occur in people who take doses above 10,000 IUs per day.

Signs and symptoms of vitamin D toxicity may include:

• Constipation
• Dehydration
• Vomiting
• Irritability or altered mental status
• Excess thirst
• Frequent urination
• Severe bone pain
• Kidney problems, such as kidney stones
• Heart problems

Some members of MyMSTeam have wondered whether vitamin D supplements can cause urine to smell — and if so, whether it’s an indication that their vitamin D levels are too high. Several vitamins, including vitamin B-6, can cause urine smell to change. Although a strong smell to your urine probably doesn’t mean vitamin D toxicity, it may indicate that you are dehydrated, which can in turn be a sign of excess vitamin D. Strong-smelling urine could also indicate a urinary tract infection.

If you’re worried you may have taken too much vitamin D, contact your doctor right away. In some cases, vitamin D toxicity can cause permanent kidney damage.

Talk to Your Doctor First About Your Vitamin D Levels

Before you start taking vitamin D supplements, talk to your doctor about whether or not you have low vitamin D levels. In general, you should always talk to your medical care team before starting a new nutritional, vitamin, or herbal supplement.

Your doctor or other health care professional, such as a clinical pharmacist or dietitian, can also help determine the dosage of vitamin D you may need to take depending on your other health conditions. For example, people with renal insufficiency (a type of kidney problem) may need supplements with different vitamin D concentrations to achieve the same result.

Vitamin D supplements may interact with other drugs, such as:

• Certain cholesterol drugs, like atorvastatin (Lipitor)
• The heart medicine digoxin (Lanoxin)
• Steroids
• High blood pressure medications
• Laxatives

If you’re taking other medications, speak with your doctor before starting vitamin D supplements to find out if they’re right for you and what a safe dosage will be.

Testing Vitamin D Levels

Your doctor may perform blood tests to track your vitamin D status and find out if your vitamin D levels are normal.

One MyMSTeam member wrote about their experience with this process: “I had a blood test to determine my vitamin D (25OHD) level twice a year, in mid-April and mid-October. Depending on the test result, my doctor would adjust the supplementation level for the next six months.”

If the levels are low, your doctor may recommend you take vitamin D supplements. People at higher risk for vitamin D deficiency usually have levels less than 30 nanomoles per liter. Levels of 50 nanomoles per liter or 20 nanograms per milliliter or more are considered normal and sufficient for most people.

Talk With Others Who Understand

MyMSTeam is the social network for people with multiple sclerosis and their loved ones. On MyMSTeam, more than 184,000 members come together to ask questions, give advice, and share their stories with others who understand life with MS.

Do you have low vitamin D levels? Has improving vitamin D levels improved your symptoms? Share your experience in the comments below, or start a conversation by posting on MyMSTeam.