Vitamin D is an essential nutrient that supports bone health and the immune system. Scientists have been studying how vitamin D relates to thyroid disorders like Graves’ disease and thyroid eye disease (TED). Some studies suggest that low vitamin D levels may be tied to thyroid problems, but scientists are still figuring out what that connection means. In this article, we’ll look at what vitamin D may do in thyroid eye disease, how it might affect symptoms, and whether taking a supplement could help people at risk.

What Is Vitamin D?

Vitamin D is a fat-soluble vitamin, meaning it dissolves in fats and is stored in the body's fatty tissues. It plays an essential role in:

• Maintaining healthy bones and teeth
• Keeping the immune system healthy
• Maintaining muscle function
• Supporting brain health
• Enhancing calcium absorption in the gut

Keeping your vitamin D at a healthy level is important for everyone and supports overall well-being.

How Do You Get Vitamin D?

Your body produces vitamin D naturally when your skin is exposed to sunlight. However, certain factors can reduce how much vitamin D your body makes:

• Geographic location — People living in colder climates or cloudy areas may get less sun.
• Sunscreen use — Sunscreen protects your skin from UV rays, but it can also make it harder for your body to make vitamin D.
• Skin color — Darker skin has more melanin, which reduces the skin’s ability to produce vitamin D from sunlight.
• Time spent indoors — Limited time outdoors due to work, lifestyle, or medical conditions can lower vitamin D levels.

For many people, sunlight alone may not provide enough vitamin D, especially in the winter months or for those who spend a lot of time indoors.

Food Sources of Vitamin D

Some foods have a lot of vitamin D and can help you keep your levels up, especially if you don’t get much sun. Good sources include:

• Fatty fish such as salmon, mackerel, sardines, and tuna
• Fortified foods like milk, orange juice, and cereal
• Egg yolks and cheese
• Mushrooms exposed to sunlight, which also produce vitamin D

However, even with a balanced diet, it may be challenging to get enough vitamin D from food alone, particularly for those at risk of deficiency. It’s a good idea to talk about your needs with a healthcare provider.

Vitamin D Supplements

For people who are deficient or at risk of deficiency, vitamin D supplements can be an effective way to boost levels. Vitamin D in supplements comes in two forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Research shows that D3 is generally more effective at raising and maintaining vitamin D levels in the blood.

Before starting a supplement, it’s important to consult with a healthcare provider to determine the right dosage for you, as needs can vary based on factors like age, health conditions, and existing vitamin D levels.

The Role of Vitamin D in the Immune System

Your body needs vitamin D to keep your immune system healthy. It helps regulate the activity of immune cells, such as T cells and B cells, which are important for fighting infections. Vitamin D also plays a role in preventing the immune system from mistakenly attacking the body’s own tissues, which is particularly important in autoimmune conditions like thyroid eye disease and Graves’ disease.

Vitamin D and Autoimmune Diseases

Research suggests that low vitamin D levels are common among people with autoimmune conditions, including TED and Graves’ disease. Some studies suggest that having enough vitamin D may help lower inflammation. But researchers still don’t know whether vitamin D directly affects how these conditions develop or progress. For now, talk with your doctor about checking your vitamin D levels and treating any low levels as part of your care plan.

What Does the Research Say About Vitamin D and Thyroid Conditions?

Research suggests a possible link between vitamin D deficiency and autoimmune thyroid conditions like Graves’ disease and thyroid eye disease. Some studies have found that people with Graves’ disease and TED often have lower vitamin D levels compared to those without these conditions. This finding has led some researchers to explore whether low vitamin D levels might increase the risk of developing these disorders.

Studies show a link between low vitamin D levels and these conditions, but researchers still don’t know if low vitamin D actually causes them or makes them worse. More research is needed to determine whether vitamin D supplements could help prevent or manage Graves’ disease or TED.

Should People With TED or Graves’ Disease Take Vitamin D Supplements?

Vitamin D supplements may help people with Graves’ disease or TED if they have low vitamin D. Keeping your levels in a healthy range supports overall health, including the immune system. Even so, there’s no strong evidence that vitamin D changes how TED progresses, and it doesn’t replace standard TED treatments. More studies are needed to know whether vitamin D supplements can improve TED symptoms.

Can Vitamin D Prevent TED in People With Graves’ Disease?

For those with Graves’ disease who haven’t developed TED, there’s no strong evidence that taking vitamin D supplements will prevent TED. Research on this is limited. Keeping your vitamin D levels healthy is important, but it shouldn’t be seen as a way to prevent TED. Additionally, some research suggests that vitamin D supplements do not prevent a recurrence of Graves’ disease once it has been treated.

Will Vitamin D Supplements Affect Your Disease Course or Symptoms?

There is currently no solid evidence that vitamin D supplements can significantly change the course of TED or Graves’ disease. However, correcting a vitamin D deficiency can still be beneficial for your overall health, including supporting immune system function, muscle health, and bone strength. While this may positively influence your general well-being, it may not directly impact the symptoms or progression of TED. Talk with your healthcare provider to figure out the approach that’s right for you.

Join the Conversation

On TEDhealthteam, people share their experiences with thyroid eye disease, get advice, and find support from others who understand.

Are you living with thyroid eye disease? How do you make sure you get enough vitamin D? Let others know in the comments below.