Vitamin D deficiency is linked with psoriatic disease. Getting enough of the sunshine vitamin may help lower inflammation in the body that’s linked to psoriasis and psoriatic arthritis.

Psoriatic arthritis (PsA) is an inflammatory type of arthritis. It affects about 1 in 3 people who have psoriasis.

Psoriasis and PsA are autoimmune conditions. They develop when the immune system accidentally attacks otherwise healthy parts of the body. Psoriasis affects the skin, and PsA affects the joints.

Vitamin D is a nutrient that the body makes when exposed to the sun. This vitamin is important for bone health, and it also seems to regulate levels of several inflammatory proteins.

Research suggests that vitamin D deficiency is associated with higher levels of inflammation in the body. Vitamin D may also be involved in promoting a normal immune response. This may be significant for the prevention of autoimmune diseases.

Here’s what we know so far about the link between vitamin D and PsA.

Low vitamin D levels are common. It’s estimated that about 35% of adults in the United States have vitamin D deficiency.

Low levels of vitamin D are associated with various inflammatory conditions, including PsA. Studies show a wide range when it comes to rates of vitamin D deficiency in PsA. One study involving 300 participants with psoriasis and PsA found that 74.9% had low vitamin D levels.

People with PsA are considered a group at risk of vitamin D deficiency. Low vitamin D levels are associated with higher levels of inflammation in people with PsA. Several studies, including one from 2022, suggest that low vitamin D levels are also associated with increased PsA disease activity.

As such, researchers have been trying to understand how vitamin D may play a role in PsA management.

Vitamin D has long been used as part of topical treatment for psoriasis. It works by reducing inflammation in the skin, helping alleviate the itchiness and discomfort of psoriasis lesions.

But so far, research on whether an oral vitamin D supplement is beneficial for PsA is inconclusive. Some studies show a decrease in inflammatory proteins in people who took a vitamin D supplement. Other studies show no improvement.

There’s a possibility that inflammation lowers the amount of vitamin D in the body. This would increase the amount of vitamin D that you need to stay in a normal range.

The Medical Board of the National Psoriasis Foundation released dietary guidelines in 2018 recommending that people with PsA take a vitamin D supplement or a vitamin D analog. They made this recommendation using what they call “weak evidence” due to a lack of consistent data.

Psoriatic arthritis is recognized as a systemic condition. The inflammation of PsA increases the risk of other inflammatory conditions, such as metabolic syndrome and heart disease. Research has suggested that vitamin D deficiency can increase the risk of metabolic syndrome and heart disease.

Getting enough vitamin D may help regulate inflammation in the body and reduce health risks associated with PsA.

Most people who have vitamin D deficiency don’t realize it. Some may feel fatigued or weak, though it’s often asymptomatic. Therefore, the best way to know if your vitamin D levels are low is by getting blood work to check your levels.

From there, you can talk with your doctor about whether or not you’d benefit from taking a vitamin D supplement.

There are three main ways to get more vitamin D.

Sun exposure

The main source of vitamin D is the sun. Our body makes vitamin D when exposed to sunlight. There are many variables that affect how much vitamin D a person is able to make from the sun, including:

  • the time of year
  • your geographic location
  • the amount of skin exposed
  • the time of the day
  • your skin tone
  • the amount of air pollution
  • your use of sunscreen

With the risk of skin cancer, it’s recommended to use sunscreen before spending time in the sun. But it’s important to note that sunscreen with SPF 8 or higher will block UV rays and reduce the amount of vitamin D the body can make.


Food sources of vitamin D include:

  • vitamin D-fortified milk and milk alternatives
  • egg yolks
  • fatty fish
  • other vitamin D-fortified foods, including margarine, yogurt, and breakfast cereal

However, unless you’re following a Mediterranean diet, most people don’t get enough vitamin D from diet alone.


Vitamin D supplements are the most reliable and safe way to consistently meet vitamin D needs. The National Institutes of Health recommend that adults ages 19 to 70 need 15 mcg (600 IU) of vitamin D daily. Adults over age 70 need 20 mcg (800 IU) of vitamin D daily.

These current recommendations on supplements are lower than previous recommendations. As researchers continue to learn about vitamin D, we’re learning that more is not always better.

Psoriatic arthritis is an inflammatory condition. Vitamin D is a nutrient that appears to have some anti-inflammatory properties. Many people with PsA have vitamin D deficiency. Low vitamin D levels are associated with increased disease activity.

So far, research is not conclusive about whether vitamin D improves PsA. Still, guidelines suggest people with PsA should take a daily supplement.

It’s a good idea to have your vitamin D levels checked. If your levels are low, taking a vitamin D supplement can help you get your levels into a normal range. There are potential benefits to vitamin D supplementation, even if it doesn’t improve PsA symptoms.