Ask the Dietitian: What Should I Know About Vitamin D and Psoriasis?

Vitamin D and psoriasis have a long and well-documented connection.

If you have psoriasis, you may have heard about the benefits of vitamin D. Perhaps your doctor has recommended light treatments or talked about getting sunlight regularly to increase your vitamin D. It sounds so simple, but the sunshine vitamin can really affect your psoriasis.

Light therapy, also known as phototherapy, is used to decrease the immune response in the area affected by psoriasis. Sun exposure has the same effect but is not as targeted as light therapy.

What is vitamin D?

Vitamin D is an essential and fat-soluble vitamin that your body produces by converting ultraviolet (UV) rays. Research from 2011 about vitamin D deficiencies in people with psoriasis has shown that the vitamin can help treat psoriasis and keep skin healthy.

While vitamin D is synthesized by the body from sunlight, it can also be taken orally as a supplement and applied topically to the skin as an oil. It can even be found in some foods.

Research on vitamin D and psoriasis

The same 2011 study mentioned above found that vitamin D can help strengthen your immune system. Specifically, vitamin D assists in the Type 1 helper cell (Th1) pathway, an important pathway in the immune system. Psoriasis symptoms are associated with inflammation and proteins found in the Th1 pathway.

Additionally, vitamin D plays an important role in inflammation function. Vitamin D has an anti-inflammatory effect on immune system cells and has been found to reduce pro-inflammatory proteins.

Vitamin D also helps maintain a healthy skin barrier. Studies suggest there may be a link between the vitamin D receptor (VDR) and psoriasis susceptibility. This means that, if the skin barrier is weakened by low vitamin D, it’s more vulnerable to infection and inflammatory conditions like psoriasis. However, more research is needed.

Many people experience low vitamin D stores, especially those who:

• are older
• have darker skin
• live in parts of the world where there’s not a lot of sunlight

Low vitamin D levels have been associated with elevated markers of inflammation, which can affect psoriasis.

Other studies have found low vitamin D levels in people with psoriatic arthritis. These studies also found that the lower the vitamin D status, the worse the psoriatic arthritis activity was in the person.

Topical or oral vitamin D: Which is better?

The benefits of sunlight exposure have been known and used for decades as a psoriasis treatment. Vitamin D therapy is one of the most popular therapies for psoriasis, whether used alone or in combination with corticosteroids.

Vitamin D has also been found to successfully treat psoriasis when used topically, particularly with the hormonally active form of vitamin D, commonly known as vitamin D3. Synthetic vitamin D has shown to slow plaque formation, thin or flatten plaques, reduce scaling, and can help treat scalp and nail psoriasis.

One older study from 1996 of 85 psoriasis patients found that 88 percent saw improvement in their psoriasis after taking a vitamin D supplement.

While that study is promising, research on oral vitamin D supplements is lacking. More research needs to be performed to gain a clearer understanding of the benefits of vitamin D and whether too much could have negative effects.

Oral vitamin D supplements can be taken as a pill, capsule, or liquid. The current recommendations are 400 to 1000 IU daily. Talk with your doctor to find out what dose is best for you. They may recommend starting with a lower dose and gradually increasing it.

Vitamin D can also be found naturally in fatty fish flesh, beef, egg yolks, and cheese, though the levels can depend on the animal’s diet. Mushrooms and foods that have been fortified with vitamin D, such as milk and cereals, are also good sources of vitamin D.

The takeaway

The research on topical vitamin D and psoriasis is well established, but more research needs to be done on oral vitamin D. People should work closely with their doctor to determine an appropriate treatment plan.

People with a personal or familial history of skin cancer may decide against UV light treatments and opt for topical or oral vitamin D. You and your care team may decide to use other medications in addition to vitamin D for added benefits.

Like everything with psoriasis, the effects of vitamin D on symptoms can differ from person to person, so your treatment plan must be tailored to best fit your needs.