Vitamin D is an essential nutrient that plays a vital role in bone health and immune function. Recent research has explored its connection to thyroid disorders like Graves’ disease and thyroid eye disease (TED), raising questions about whether vitamin D deficiency could influence the development of these conditions. While some studies suggest a link between low vitamin D levels and thyroid conditions, the evidence is still evolving.

In this article, we’ll explore what we know about vitamin D’s role in thyroid eye disease, how it might affect your symptoms, and whether supplementation could be beneficial for those 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 healthy levels of vitamin D is important for everyone, not just those with autoimmune conditions. Consistent levels support 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 — While sunscreen protects your skin from UV rays, it can also limit vitamin D production.
• 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

Certain foods are rich in vitamin D and can help you maintain healthy levels, especially if you have limited sun exposure. Some good dietary 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 discuss your needs with a health care 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 health care 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

Vitamin D is essential for a healthy immune system. 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 indicate that maintaining adequate vitamin D levels might help reduce inflammation, but more research is needed to understand whether vitamin D can directly influence the development or progression of these conditions. For now, it’s advisable to work with your doctor to monitor your vitamin D levels and address any deficiencies as part of your overall 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 has led some researchers to explore whether low vitamin D levels might increase the risk of developing these disorders.

However, while the association between low vitamin D levels and these conditions is clear, it remains uncertain if vitamin D deficiency directly contributes to their development or progression. More research is needed to determine whether vitamin D supplementation could help prevent or manage Graves’ disease or TED.

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

Vitamin D supplements may be helpful for people with Graves’ disease or TED if they have a deficiency. Maintaining adequate vitamin D levels supports overall health, including immune function. Even so, there’s no strong evidence that vitamin D directly influences the progression of TED, and it is not a replacement for TED treatments. It is important to view vitamin D as a supportive measure rather than a replacement for standard TED therapies. More studies are needed to confirm whether vitamin D supplementation can improve TED symptoms.

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

For those with Graves’ disease who have not developed TED, there is no conclusive evidence that taking vitamin D supplements will prevent TED from occurring. Research in this area is limited, and while maintaining adequate vitamin D levels is important, it should not be considered a preventive measure for 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 alter 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. Always consult with your health care provider to determine the right approach for your needs.

Talk With Others Who Understand

TEDhealthteam is the social network for people with thyroid eye disease and their loved ones. On TEDhealthteam, hundreds of members come together to ask questions, give advice, and share their stories with others who understand life with thyroid eye disease.

Are you living with thyroid eye disease? How do you make sure you get enough vitamin D? Share your experience in the comments below, or start a conversation by posting on your Activities page.