If you have Parkinson’s disease, you may be curious about the role of vitamin D in your symptoms and the condition’s progression. “My blood work shows that I am very low on vitamin D. Does this have anything to do with Parkinson’s disease?” asked one MyParkinsonsTeam member.

One 2020 study indicated that “a high prevalence of vitamin D deficiency has been noted in Parkinson’s disease and also other neurological diseases for at least the past two decades.” But the evidence connecting vitamin D and Parkinson’s symptoms and disease progression is still unclear.

In order to make informed decisions about whether you should add more vitamin D to your diet or take supplements, think about a few key considerations.

1. Vitamin D Is an Essential Nutrient

Vitamin D is a nutrient that your body needs to make your muscles move, help your nerves send signals, and allows 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.

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

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

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.

2. People With Parkinson’s Tend To Have Low Vitamin D Levels

Researchers have found that vitamin D levels are consistently lower in people with Parkinson’s disease than in the general population. There are several potential reasons for this and not all point toward direct causality — that is, there’s no evidence that low vitamin D levels cause Parkinson’s nor that Parkinson’s causes low vitamin D levels. One potential reason people with Parkinson’s may have lower vitamin D levels is, they engage in fewer outdoor activities and thus have less sun exposure.

However, studies have shown that vitamin D levels have the potential to affect many nonmotor symptoms of Parkinson’s disease, possibly including verbal fluency and memory, mood, and smell impairment. In addition, one of the most common findings is that serum levels of vitamin D may be associated with motor symptoms seen in those with Parkinson’s disease.

A vitamin D deficiency may be related to higher levels of nitric oxide, which can damage your neurons (nerve cells). More research is needed to determine conclusively whether low vitamin D levels put you at an increased risk of Parkinson’s disease.

If you’re concerned about your vitamin D status, talk to your doctor. They can order a blood test to assess your levels.

3. Vitamin D Supplements Carry Potential Risks

Some people consider taking vitamin D supplements to make up for deficiencies. Talk to your health care team if you’re thinking about vitamin D supplementation, particularly because there’s a risk of taking too much. The general recommended dose for vitamin D supplements is 600 international units (IUs) for adults under 70 and 800 IUs for adults over 70.

The U.S. 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 MyParkinsonsTeam, the social network and online support group for people with Parkinson’s disease and their loved ones, members discuss the chronic nature of the disease. Here, more than 94,000 members from across the world come together to ask questions, offer advice and support, and share stories with others who understand life with Parkinson’s.

Are you working to increase your vitamin D intake? Share your experience in the comments below, or start a conversation on MyParkinsonsTeam.