Wilson Liao, MD, professor and vice chair of research in the Department of Dermatology at the University of California, San Francisco (UCSF) School of Medicine, and colleagues conducted a study examining the role of supplements and diets in managing psoriasis.
A review published in Psoriasis: Targets and Therapy examines the role of supplements and diet in managing the disease. Wilson Liao, MD, professor and vice chair of research in the Department of Dermatology at the University of California, San Francisco (UCSF) School of Medicine, and colleagues conducted the review. Study authors searched PubMed, Embase, and the Cochrane databases from 2017 to November 2021. A variety of terms were searched along with the keyword psoriasis, including combinations of diet, food, and nutrition, among others.1
Prior to 2017, Liao and colleagues used a review by Ford et al, but also searched psoriasis, microbiome and other Medical Subject Headings terms.2 Investigators also conducted manual searches of bibliographies. Topical treatments were excluded. A low-calorie diet that helped patients with obesity to lose weight may be helpful, according to studies found by the review. “Low-calorie diets have been linked to a better response to systemic psoriasis treatment, making it a useful adjunctive treatment,” investigators said, citing a randomized study by Gisondi et al.3 In that study, patients with psoriasis who were obese and on cyclosporine in the low-calorie diet group responded better to treatment than those in the control group. Certain negative adverse effects (AEs) of select biologics such as tumor necrosis factor–α inhibitors may also be mitigated by low-calorie diets based on a study by Campanati et al, Liao and colleagues reported.4 Researchers noted that intermittent fasting did not contain enough supporting evidence to be of use.
A gluten-free diet for patients with psoriasis seemed only to benefit those with celiac disease or gluten sensitivity. “The Mediterranean diet has continually shown positive benefits in both skin and systemic outcomes,” Liao et al reported.1 Study authors said although randomized controlled trials are still limited, there is good evidence for recommending this diet, and it is supported by academic bodies. “High consumption of antioxidants, including red wine and plant-based foods, may impart anti-inflammatory benefits to those following this diet,” investigators noted.1
The ketogenic diet did not have strong enough evidence to be recommended, Liao et al said. Investigators advised avoiding the Western high fat, high sugar diet due to inflammation, instead recommending fresh food and polyunsaturated fatty acids such as those found in fish oil.
Liao et al said there was not enough evidence to recommend most supplements to treat psoriasis. Some herbal supplements such as Tripterygium wilfordii and curcumin (chemical name, [E,E]-1,7-Bis[4hydroxy-3-methoxyphenyl]1,6-heptadiene-3,5-dione) may be promising, but researchers noted these should not be recommended because of possible drug interactions and lack of regulation.
According to Liao et al, the gut microbiome of patients with psoriasis has been found to differ from controls, and that this may be an avenue for probiotic research for treatment. “Probiotics have been shown to modify the gut microbiome in a multitude of inflammatory skin diseases. These results appear especially promising because of the specificity of the bacterial strains needed to induce change, as well as a dose-response relationship… seen in a multitude of clinical trials,” researchers said.1 However, the investigators noted that negative AEs are possible with antibiotic treatment.
In an interview with Dermatology Times®, Mimi Chung, BA, former research fellow at UCSF who worked on the review, said the most important takeaway from the study was for dermatology providers to emphasize to patients that nutrition influences psoriasis. She added that patients should be counseled on a healthy diet as an important aspect of comprehensive care. “Diets like the Mediterranean diet have stronger evidence for success than supplements,” she said. Chung said next steps for the research would be to investigate probiotics, which may provide insight into the role of the gut microbiome in psoriasis.