If you have myeloma, you may be curious about the role vitamin D plays in your overall health. As one MyMyelomaTeam member wrote, “I take calcium supplements and vitamin D3, as my vitamin D has been low.” Another said, “I take vitamin D every day. I was given this when I was diagnosed with multiple myeloma.”

It’s important to understand whether there are any connections between vitamin D intake and myeloma and if you should do anything to evaluate whether you have enough vitamin D in your diet.

What Is Vitamin D?

Vitamin D is a nutrient that your body needs to make your muscles move, help your nerves send signals, and allow your immune system to fight off bacteria and viruses that can make you sick. Vitamin D is also important so bones can absorb the calcium they need to be strong and healthy.

There are two kinds of vitamin D: vitamin D2 and vitamin D3. Vitamin D2 is mostly found in plants, mushrooms, and yeast. Vitamin D3 can be found in oily fish and is also made in the body during sun exposure. Additionally, vitamin D3 is later converted to 25-hydroxy-cholecalciferol, which affects how the transcription of genes related to vitamin D are up- and downregulated.

According to the Cleveland Clinic, foods that are good sources of vitamin D include:

• Beef liver
• Fortified cereal
• Fish (such as salmon, sardines, swordfish, and cod liver oil)
• Egg yolks
• Fortified milk and orange juice

Your body converts vitamin D into its active form, called 1,25-dihydroxyvitamin D — which is also known as calcitriol and can be found as a supplement. This active form of vitamin D can affect the cells involved in the immune system.

Is Vitamin D Deficiency Linked to Myeloma?

Several studies have found that people with myeloma are often deficient in vitamin D. However, oncologists haven’t traditionally prioritized vitamin D screenings in individuals with multiple myeloma, one study noted.

Because of the high prevalence of vitamin D deficiency in this community, experts have indicated that a standard of care should be created to establish testing and supplementation guidelines among people with myeloma.

Vitamin D is important for bone health, which is affected by myeloma. Through a proliferation of cancer cells, the disease can lead to bone pain, thinning bones, and broken bones, according to the Mayo Clinic.

Researchers have also found that vitamin D deficiency can lead to worse myeloma outcomes. For instance, one study found that individuals who were deficient in vitamin D experienced a 24 percent increased mortality risk when compared to those with normal vitamin D levels. In addition, worse outcomes were seen among white participants who were low in vitamin D than in Black study participants.

However, other studies have indicated that associations between vitamin D levels and myeloma risk or prognosis do not prove causation. In other words, other factors besides vitamin D levels could account for the outcomes in individuals with myeloma, and a cause-and-effect relationship between the vitamin and the condition has not been solidified.

Considering what the research indicates regarding vitamin D and myeloma, you may be wondering if taking vitamin D supplements is right for you.

Should You Take Vitamin D Supplements?

Although many previous studies have shown promising results, oncology researchers emphasize the importance of further clinical trials to investigate the effectiveness of vitamin D on people with myeloma.

Talk to your health care team if you’re considering adding vitamin D supplements to your diet because you can also run the risk of taking too much.

The Office of Dietary Supplements warns that too much vitamin D can cause nausea and vomiting, muscle weakness, confusion, pain, dehydration, and kidney stones, among other side effects. Vitamin D can also interact with some medications, so don’t start any supplementation plan before speaking with your physician.

Talk With People Who Understand

On MyMyelomaTeam, the social network and online support group for people with myeloma and their loved ones, members discuss the chronic nature of the disease. Here, more than 11,700 members from across the world come together to ask questions, offer advice and support, and share stories with others who understand life with myeloma.

Have you ever investigated your vitamin D levels? Share your experience in the comments below, or start a conversation on MyMyelomaTeam.