If you have ovarian cancer, you may be curious about how vitamin D may affect your condition and your overall well-being. As one MyOvarianCancerTeam member said, “If you take vitamin D, ask your doctor if you are deficient. You may have to double it like I did.”

There is an ongoing debate in the scientific community about vitamin D’s potential to help people with ovarian cancer, and taking in all of that seemingly conflicting information can sometimes feel overwhelming. Here are some factors to consider in investigating your vitamin D levels.

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 helps turn on and off the genes that allow vitamin D to carry out its function in the body.

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

• Beef liver
• Fortified cereal
• Fish (such as salmon, sardines, herring, swordfish, and cod liver oil)
• Egg yolks
• Fortified milk and orange juice
• Some vegetables such as kale, okra, spinach, white beans, soybeans

Your body breaks vitamin D down 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.

Vitamin D and Ovarian Cancer — Is There a Link?

Vitamin D is known for its health benefits and potentially preventative effects on several types of cancer, so people with ovarian cancer may wonder what effect the nutrient may have on their condition. Checking your vitamin D levels is very easy using a blood test.

Some research shows that a vitamin D deficiency may be a risk factor for the development of ovarian cancer. The properties of vitamin D can potentially reduce the processes that make cancer cells multiply. One reason for this may be that vitamin D can promote apoptosis, or cell death, in ovarian cancer cell lines.

Additionally, some studies show that vitamin D supplementation can be helpful for people already affected by ovarian cancer. One recent meta-analysis found a 13 percent mortality decrease among people living with cancer who took vitamin D supplements.

On the other hand, some studies have found that vitamin D may not be helpful in lowering the risk of ovarian cancer. A 2021 study, which investigated the effects of vitamin D and calcium intake on ovarian cancer risk, found that “supplementation with calcium plus vitamin D was not effective for the prevention of ovarian cancer.”

According to other research, there may not be a direct link between levels of vitamin D serum and ovarian cancer risk. However, there may be more complicated processes related to how one’s genes and the environment interact with each other. These findings may explain why in some cases, vitamin D has been found to be effective in treating ovarian cancer.

Should You Take Vitamin D Supplements?

Scientists still haven’t performed enough research to definitively determine whether vitamin D supplementation would be effective for people with ovarian cancer across the board.

Additionally, there is a risk that comes along with taking too much vitamin D. The federal 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.

It's important to have a conversation with your oncologist before starting on any supplements, as your physician can best advise you regarding how they may affect your specific case. Monitoring a vitamin D deficiency is only one part of your cancer care, and having open conversations about your concerns is the best way for you and your doctor to be on the same page about your treatment goals.

Talk With People Who Understand

On MyOvarianCancerTeam, the social network and online support group for people with ovarian cancer and their loved ones, members discuss the chronic nature of the disease. Here, more than 2,000 members from across the world come together to ask questions, offer advice and support, and share stories with others who understand life with ovarian cancer.

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