“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.”
This analysis is one of the largest studies to date, including almost 500 cases of psoriasis from the National Health and Nutrition Examination Survey (NHANES), showing a linear relationship between the severity of psoriasis and decreasing vitamin D levels which were measured through blood tests.
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.”
491 psoriasis cases were identified from over 40,000 participants who were enrolled in the NHANES study, with 162 cases from 2003-2006 and 329 from 2100-2014, extracting data on vitamin D levels, self-reported psoriasis affected body surface areas, and other factors such as race, smoking status, BMI, age, and gender.
After adjusting for various lifestyle factors the analysis showed that lower vitamin D levels and vitamin deficiency were significantly associated with greater severity of psoriasis. Those with the least amount of body surface affected by the condition were found to have the highest average vitamin D levels, while those with the greatest affected areas 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.”
It was noted that even though dietary vitamin D toxicity is rare, it is still advised for those with and those without psoriasis to consult with their physician and/or dermatologist before taking any supplements
