New Study: Vitamin D Could Ease Psoriasis Severity

New research indicates that the consumption of vitamin D-rich foods or the use of supplements could be beneficial for those dealing with psoriasis.

Over eight million individuals in the U.S. are affected by psoriasis, a skin disorder that results in cells accumulating and forming dry, itchy patches. Now, one of the largest studies to date reveals that the severity of psoriasis might be significantly influenced by an individual’s vitamin D levels.

The analysis included almost 500 psoriasis cases from the National Health and Nutrition Examination Survey (NHANES). The findings revealed a direct correlation between elevated psoriasis severity and lowered levels of vitamin D, measured by blood tests.

“Topical synthetic vitamin D creams are emerging as new therapies for psoriasis, but these usually require a doctor’s prescription,” said Rachel K. Lim, an MD candidate at the Warren Alpert Medical School of Brown University. “Our results suggest that a vitamin D-rich diet or oral vitamin D supplementation may also provide some benefit to psoriasis patients.”

Lim recently presented findings at NUTRITION 2023, the annual flagship meeting of the American Society for Nutrition held July 22-25 in Boston.

The research team was led by Eunyoung Cho, ScD, an associate professor in the Department of Dermatology at the Warren Alpert Medical School of Brown University who studies the role of nutrition and environmental factors in skin cancer and inflammatory skin diseases such as psoriasis. Vitamin D is thought to influence the development of skin diseases by affecting the body’s immune response and through direct effects on the cells involved in skin repair.

“With growing public interest in vitamin supplementation, we wanted to further examine the connection between vitamin D levels and psoriasis severity,” said Cho. “Few studies have looked for this association in groups of people, especially in large U.S. populations, or examined this relationship through a clinical nutrition lens.”

For the new study, the researchers identified 491 psoriasis cases from more than 40,000 NHANES participants, with 162 cases from 2003-2006 and 329 from 2011-2014. They also extracted data on vitamin D levels, self-reported psoriasis-affected body surface area, and other factors including age, gender, race, body mass index, and smoking status.

After adjusting for lifestyle factors such as smoking, the analysis showed that lower vitamin D levels and vitamin D deficiency were significantly associated with greater psoriasis severity. The researchers also found that patients with the least amount of body surface affected by psoriasis had the highest average vitamin D levels while those with the greatest affected area had the lowest average levels of vitamin D.

“Only one previous study, published in 2013, has used NHANES data to analyze the relationship between vitamin D and psoriasis,” said Lim. “We were able to add more recent data, which more than tripled the number of psoriasis cases analyzed, making our results more up-to-date and statistically powerful than previously available data.”

Although dietary vitamin D toxicity is rare, the researchers advise people with psoriasis to consult their physicians and dermatologists before taking supplements.

Reference: “Association of Serum Vitamin D Levels and Psoriasis Severity: An Analysis of the US National Health and Nutrition Examination Survey” by Rachel K. Lim, Seungmin Woo, Sherif El Raheb, Abrar Qureshi and Eunyoung Cho, 25 July 2023, NUTRITION 2023 (abstract; presentation details).