Psoriasis is a chronic immune-mediated inflammatory skin disease. Psoriasis lesions are characterized by hyper-proliferation of epidermal keratinocytes associated with inflammatory cellular infiltrate in both dermis and epidermis. The epidermis is the natural source of vitamin D synthesis by sunlight action. Recently, a role for vitamin D in the pathogenesis of different skin diseases, including psoriasis, has been reported. Indeed, significant associations between low vitamin D status and psoriasis have been systematically observed. Due to its role in proliferation and maturation of keratinocytes, vitamin D has become an important local therapeutic option in the treatment of psoriasis. To date, the successful treatment based on adequate dietary intake of vitamin D or oral vitamin D supplementation in psoriasis represent an unmet clinical need and the evidence of its beneficial effects remains still controversial. This information is important either for Dermatologists and Nutritionists to increases the knowledge on the possible bi-directional relationships between low vitamin D status and psoriasis and on the potential usefulness of vitamin D in psoriasis with the aim not only to reduce its clinical severity, but also for delineating the risk profile for co-morbidities cardiac risk factors that may result from psoriasis. In the current review, we analyzed the possible bi-directional links between psoriatic disease and vitamin D.

BackgroundMany studies have evaluated the role of individual nutrients on the development of psoriasis. However, only few studies have investigated the effect of a healthy eating pattern, such as the Mediterranean diet. In this study, we aimed to investigate the relationship between adherence to the Mediterranean diet, the body composition and the severity of psoriasis in a group of naïve-treatment patients with psoriasis.MethodsThis is a cross-sectional case–control observational study. Sixty-two patients (49 males and 13 females, mean age: 50.2±10.5yrs) affected with mild-to-severe psoriasis were consecutively enrolled. Sixty-two age-, sex- and body mass index (BMI)-matched healthy subjects served as control group. A validated 14-item questionnaire (PREDIMED: PREvención con DIeta MEDiterránea) was used for the assessment of adherence to the Mediterranean diet. The severity of psoriasis was by assessed by standardized Psoriasis Area and Severity Index (PASI) score and C-reactive protein (CRP) levels. Body composition was analyzed with bioelectrical impedance analysis.ResultsA higher percentage of psoriatic patients had a lower PREDIMED score compared to the control group (30.6% vs 4.8%). PASI score was significantly associated with the percentage of fat mass (FM%) and CRP levels. PASI score and CRP levels were significantly associated with the dietary components included in the PREDIMED questionnaire or with the PREDIMED score. At multiple regression analysis, the major predictor of PASI score were FM among BIA parameters, (r2=0.537, β=0.740, p<0.001), and FM (r2=0.537, β=0.603, p<0.001) and PREDIMED score (r2=0.599, β=−0.296, p=0.007) among anthropometric measures, FM and PREDIMED score. Finally, among all items of the PREDIMED questionnaire, EVOO (r2=0.548, β=−0.741, p<0.001), and fish consumption (r2=0.139, β=−0.372, p=0.005) have an independent predictive value for PASI score and CRP levels.ConclusionsThis is the first study to evaluate the association between adherence to the Mediterranean diet and the severity of psoriasis. Moreover, our study highlights the usefulness of the assessment of body composition by bioelectrical impedance analysis in the evaluation of the psoriatic patients.

Low vitamin D status and obesity have concomitantly reached epidemic levels worldwide. Up to now the direction of the association between low vitamin D status and obesity, the exact mechanisms responsible for this association and the clinical usefulness to increase vitamin D status for reducing adiposity still warrant further evaluation. The aim of the present review was to examine the current evidence linking low vitamin D status and obesity in relation to the role of the nutritionist. On the one side, considering obesity as a causal factor, low sun exposure in obese individuals due to their sedentary lifestyle and less outdoor activity, vitamin D sequestration in adipose tissue, and volumetric dilution of ingested or cutaneously synthesized vitamin D in the large fat mass of obese patients, might represent some of the factors playing a major role in the pathogenesis of the low vitamin D status. On the other side, the expression of both vitamin D receptors and enzymes responsible for vitamin D metabolism in adipocytes depicted a role for the low vitamin D status per se in the development of obesity by modulating adipocyte differentiation and lipid metabolism. Nutritionists need to accurately address the aspects influencing the low vitamin D status in obesity and the vitamin D supplementation in obese individuals.

Psoriasis is a common, chronic, immune-mediated skin disease with systemic pro-inflammatory activation, where both environmental and genetic factors contribute to its pathogenesis. Among the risk factors for psoriasis, evidence is accumulating that nutrition plays a major role, per se, in psoriasis pathogenesis. In particular, body weight, nutrition, and diet may exacerbate the clinical manifestations, or even trigger the disease. Understanding the epidemiological relationship between obesity and psoriasis is also important for delineating the risk profile for the obesity-related comorbidities commonly found among psoriatic patients. Moreover, obesity can affect both drug’s pharmacokinetics and pharmacodynamics. Additionally, the overall beneficial effects on the obesity-associated comorbidities, clinical recommendations to reduce weight and to adopt a healthy lifestyle could improve the psoriasis severity, particularly in those patients with moderate to severe disease, thus exerting additional therapeutic effects in the conventional treatment in obese patients with psoriasis. Education regarding modifiable environmental factors is essential in the treatment of this disease and represents one of the primary interventions that can affect the prognosis of patients with psoriasis. The goal is to make psoriatic patients and health care providers aware of beneficial dietary interventions. The aim of this review is to assess the relevance of the environmental factors as modifiable risk factors in psoriasis pathogenesis, with particular regard to the involvement of obesity and nutrition in the management of psoriasis, providing also specific nutrition recommendations.

BackgroundObesity, metabolic syndrome (MetS), and psoriasis, largely driven by environmental factors, show multiple bidirectional associations, with important metabolic implications in psoriatic patients. Besides body mass index (BMI) as a measure of obesity, data on phase angle (PhA), a direct measure by bioelectrical impedance analysis (BIA), used as a marker of cellular health and a predictor of morbidity and mortality in various diseases, are still lacking in psoriasis. In this case–control, cross-sectional study, we investigated the PhA in 180 pairs of adult psoriatic patients and healthy controls, evaluating also the potential use of the PhA as marker of the clinical severity, the quality of life, and the presence of the MetS in psoriatic patients.MethodsAnthropometric measures, metabolic profile and bioelectrical variables were evaluated. The clinical severity was assessed by standardized psoriasis area and severity index (PASI) score and c-reactive protein (CRP) levels, and the quality of life was evaluated by dermatology life quality index (DLQI). MetS was diagnosed according to Adult Treatment Panel III.ResultsPsoriatic patients presented smaller PhA (p < 0.001) and higher prevalence MetS compared with controls. The PhA was significantly associated with number of parameters of MetS in both groups (p < 0.001). After adjusting for BMI, this association remained significant in psoriatic patients only (p < 0.001). Among psoriatic patients, the PhA was the major index value for the diagnosis of MetS (OR 5.87, 95 % CI 5.07–6.79) and was inversely associated with both PASI score and DLQI, independently of BMI (p < 0.001). At multiple regression analysis, the PhA well predicted the PASI score and DLQI. Based on ROC curves, the most sensitive and specific cutoffs of PhA to predict the highest PASI score and the lowest DQLI were ≤4.8° and ≤4.9°, respectively.ConclusionsWe reported that psoriatic patients presented small PhAs, with a novel association between PhA, clinical severity, quality of life in psoriatic patients, and MetS. Further studies are required to validate the PhA’s prognostic ability in assessing the clinical severity and MetS in psoriatic patients.