The so-called "sunshine vitamin" may affect the severity of the skin disease psoriasis, new research shows.
Researchers who linked vitamin D levels to psoriasis symptoms said dietary supplements could help. But it’s unclear how much vitamin D a person with psoriasis would need to benefit.
People who have psoriasis may want to monitor their vitamin D levels. New research suggests that blood levels of the so-called "sunshine vitamin" may affect the severity of their condition. In psoriasis, skin cells build up and form dry, itchy, and sometimes painful patches.
While synthetic vitamin D creams are an emerging therapy, the study suggests that a diet rich in vitamin D or oral supplements could also relieve psoriasis symptoms, said Rachel Lim, an author of the study and an MD candidate in the School of Warren Alpert Medicine at Brown University.
If the role of vitamin D can be proven after further study, "it could present a very accessible and safe addition to the treatment regimen of the millions of Americans living with psoriasis," Lim said. About 8 million Americans have psoriasis.
For the study, researchers analyzed 491 cases in a U.S. national health and nutrition survey, including 162 from 2003 to 2006 and 329 from 2011 to 2014.
Their analysis found that lower vitamin D levels and deficiency were significantly associated with more severe psoriasis.
Patients with the highest average levels of vitamin D had the least amount of skin affected by psoriasis. Those who had the most affected area had the lowest average levels of vitamin D. The amount of vitamin D a person would need to consume is unclear.
"Although we cannot speak to the optimal intake of vitamin D, there are current recommendations for safe amounts of vitamin D supplements to avoid toxicity," Lim said. "People may want to talk to their doctors about how to safely start taking vitamin D supplements."
There could also be other contributors to a person’s psoriasis. Skin pigment inhibits vitamin D synthesis, Lim said. And psoriasis affects many people with darker skin tones.
"Together with socioeconomic factors and barriers to adequate care, we might erroneously attribute the increased psoriasis severity we found with lower vitamin D levels solely to lower vitamin D levels, rather than to more complex social constructs." that obstruct attention," Lim said.
The study is a reminder that low levels of vitamin D are associated with worse psoriasis and that supplementation could help, said Dr. Deirdre Hooper, a dermatologist at Audubon Dermatology in New Orleans. Hooper was not involved in the study.
"Are we going to take away from this that all people with psoriasis should supplement with vitamin D regardless of their blood levels?" she said. "I think this is an unanswered question, but I think what I will probably do based on the study is suggest that my psoriasis patients supplement with vitamin D." Although it appears that vitamin D will improve a person’s psoriasis, it may also help with some associated health problems, such as diabetes and hypertension, Hooper said.
Sunlight is an important source of vitamins, but it is not safe to get all the vitamin D you need from the sun, because its UV rays can cause skin cancer.
And, Hooper said, although a person could get enough of the nutrient through diet, "the best way to consume vitamin D is to take a supplement."
Some foods that contain vitamin D are fatty fish, such as salmon and mackerel, and egg yolks. Some fortified foods such as cereals, milk and orange juice also contain the nutrient.
But keep in mind that food sources may not be reliable because the amount of vitamin D contained in a particular food may vary.
If a person has psoriasis and has not received medical care, Hooper recommends seeing a dermatologist. Psoriasis can affect a person’s daily life and potentially interfere with sleep. There are a variety of treatments available, including creams, light therapy, and oral and injectable medications.
"It’s constantly evolving, which is great because it’s a common and very frustrating disease and it’s associated with real systemic problems," Hooper said.
Lim was scheduled to present his findings Tuesday at a meeting of the American Society for Nutrition in Boston. Findings presented at medical meetings are considered preliminary until published in a peer-reviewed journal.
