Psoriasis: A Nutrition and Natural-Health Reference
1. Definition and Overview
Psoriasis is a chronic proliferative and inflammatory condition of the skin, characterized by erythematous plaques covered with silvery scales, particularly over the extensor surfaces, scalp, and lumbosacral region. It is a heterogeneous, chronic, systemic inflammatory disease that presents in the skin with multiple types. Psoriasis is a chronic, systemic inflammatory skin disease that affects approximately 3% or 7.5 million people in the United States. Worldwide, prevalence is approximately 1.99% in East Asia, 1.92% in Western Europe, and 1.10% in high-income Southern Latin American countries. Psoriasis occurs equally in both males and females and has a bimodal age of peak occurrence: between 20–30 and 60–70.
Psoriasis is currently viewed as a systemic chronic inflammatory disease with an immunogenetic basis that can be triggered extrinsically or intrinsically. It is a chronic recurrent inflammatory autoimmune pathology with a significant genetic component and several interferences of immunological cells and their cytokines; the complex orchestration of its pathogenesis is related to the synergic effect of immune cells, polygenic alterations, autoantigens, and several other external factors.
2. Clinical Presentation and Types
Psoriasis can present with different morphology in the form of plaque, guttate, rupioid, erythrodermic, pustular, inverse, elephantine, and psoriatic arthritis. Any injury to the skin in patients with psoriasis in the form of either mechanical, chemical, or radiational trauma induces lesions of psoriasis at that site — a phenomenon called the Koebner phenomenon — which indicates the activeness of the disease.
- Plaque psoriasis (psoriasis vulgaris): The most common form, affecting 85–90% of people with psoriasis. It typically appears as raised areas of inflamed skin covered with silvery-white, scaly skin (plaques), most commonly found on the elbows, knees, scalp, and back.
- Guttate psoriasis: Has drop-shaped lesions and is most commonly seen in children and young adults. It has a better prognosis than plaque psoriasis and typically resolves within 1–3 weeks; however, up to 40% of patients with guttate psoriasis eventually convert to plaque psoriasis.
- Inverse psoriasis: Appears as very red, smooth, and shiny lesions in body folds, such as behind the knees, under the arms, in the groin, or under the breasts, and often occurs together with other types of psoriasis.
- Pustular psoriasis: A rare entity with sterile pustules that can be localized or generalized; classically recognized subtypes include generalized pustular psoriasis (GPP), palmoplantar pustular psoriasis (PPP), and acrodermatitis continua of Hallopeau (ACH).
- Erythrodermic psoriasis: Presents with widespread inflammation in the form of erythema and exfoliation of the skin covering more than 90% of the body area. It may be accompanied by fever, chills, hypothermia, and dehydration secondary to the large body surface area involvement.
The disorder can also affect the joints and eyes. Psoriatic arthritis can cause stiffness, pain, throbbing, swelling, or tenderness of the joints; the distal joints, such as the fingers, toes, wrists, knees, and ankles, are most often affected.
3. Body Systems Involved
3.1 The Immune System
Psoriasis vulgaris is an inflammatory skin disease mediated by the cells and molecules of both the innate and adaptive immune systems, but with key responses of normal skin cells to associated products. Inflammatory myeloid dendritic cells release IL-23 and IL-12 to activate IL-17-producing T cells, Th1 cells, and Th22 cells to produce abundant psoriatic cytokines IL-17, IFN-γ, TNF, and IL-22. These cytokines mediate effects on keratinocytes to amplify psoriatic inflammation.
In the current model, a crosstalk between keratinocytes, neutrophils, mast cells, T cells, and dendritic cells is thought to create inflammatory and pro-proliferative circuits mediated by chemokines and cytokines. Various triggers, including recently identified autoantigens, Toll-like receptor agonists, chemerin, and thymic stromal lymphopoietin, may activate the pathogenic cascade resulting in enhanced production of pro-inflammatory and proliferation-inducing mediators such as IL-17, TNF-α, IL-23, IL-22, IFN-α, and IFN-γ by immune cells.
The IL-23/T17 axis represents the central immune pathway driving the development of psoriasis through the downstream effects of increased IL-17 levels. Pathogenic T cells in psoriatic skin lesions facilitate hyperproliferation of keratinocytes, influx of neutrophilic granulocytes, as well as production of other inflammatory cytokines, chemokines, and antimicrobial peptides.
3.2 The Skin (Epidermis and Dermis)
Psoriasis's manifestation lies in the epidermal keratinocytes, where the perturbation of inflammatory and cell-cycle-related pathways leads to their uncontrolled proliferation, aberrant differentiation, and the development of distinctive, erythematous plaques on the skin surface.
3.3 Genetic Architecture
Genome-wide association studies (GWASs) offer a better view of psoriasis pathogenic pathways, with approximately one-third of psoriasis's genetic impact associated with the MHC region and genetic loci located on chromosome 6. The most eloquent genetic factor of psoriasis, PSORS1, was identified in the MHC I site.
3.4 Cardiovascular and Metabolic Systems
There is solid epidemiologic evidence linking psoriasis and psoriatic arthritis (PsA) to cardiovascular risk factors and an increased risk of developing cardiovascular disease. A recent meta-analysis and systematic review of 14 cohorts identified a CVD risk in individuals with severe psoriasis: the risk ratio relative to the general population was 1.37 for CVD mortality, 3.04 for myocardial infarction, and 1.59 for stroke. Studies have shown that patients with psoriatic disease also suffer from associated comorbidities, including cardiovascular disease, obesity and metabolic syndrome, diabetes, osteoporosis, malignancy, fatty liver disease, depression, and anxiety.
Approximately 15–30% of Caucasians with psoriasis eventually develop psoriatic arthritis. In contrast to psoriatic arthritis and Crohn's disease, which share genetically based pathomechanisms with psoriasis, chronic inflammation would provide the basis for the cardiovascular and metabolic comorbidities of psoriasis.
4. Contributing and Associated Factors
4.1 Genetic Factors
Psoriasis is considered to be a genetically programmed disease of dysregulated inflammation, which is driven and maintained by multiple components of the immune system. Genetic factors play a major role in the pathogenesis of psoriasis; however, non-genetic factors are also necessary to trigger the onset and recurrence in genetically predisposed individuals, including infections, microbiota dysbiosis of the skin and gut, dysregulated lipid metabolism, dysregulated sex hormones, and mental illness.
4.2 Infections and Microbiome
The connection between psoriasis and bacterial infections was established decades ago by providing evidence that streptococcal infection can lead to psoriasis, and psoriasis patients can be distinguished from healthy individuals based on differences in their skin and gut microbiome. Psoriasis can also be induced by other environmental triggers, such as skin trauma, unhealthy lifestyles, and medications.
4.3 Psychological Stress
Among psoriasis triggers, psychological stress has emerged as a pivotal yet underappreciated contributor to disease onset and exacerbation. Evidence suggests a regulatory role of psychological stress in immune functions, including increasing expression levels of proinflammatory cytokines and ICAM-1, and decreasing anti-inflammatory cytokines and the function of glucocorticoid receptors, possibly in part via activation of the CRH-POMC-ACTH-corticosteroids axis. The onset and/or worsening of psoriasis can also be attributed to psychological stress-induced defective epidermal permeability barrier function.
4.4 Obesity
Obesity is an important risk factor for psoriasis, and the relationship between obesity and psoriasis is mutually interdependent. Obesity is one of the important components of metabolic syndrome and is a well-known risk factor for psoriatic arthritis; both obesity and PsA share a complex relationship that is likely bidirectional. Increased pro-inflammatory cytokines, secretion of adipocytokines from adipose tissue, increased oxidative and endoplasmic reticulum stress, and dysbiosis of intestinal microbiota all play a role in the development of metabolic syndrome and increase the risk of cardiovascular disease in psoriatic patients.
4.5 Alcohol and Smoking
Environmental factors — including stress, infections, certain medications, nicotine use, alcohol, and obesity — play a significant role in the pathogenesis of psoriasis. The etiology of this autoimmune disorder is unknown but is believed to be an interplay between genetic predisposition and environmental factors such as smoking, high body mass index, and excessive alcohol consumption.
4.6 Medications and Hormonal Factors
Stress, infections (especially streptococcal), alcohol, smoking, and certain medications are well-established triggers; other factors, such as hormonal changes, allergies, and irritants, also contribute to the development or worsening of psoriasis. Hormonal fluctuations, particularly during puberty, pregnancy, and menopause, can significantly influence the onset and severity of psoriasis. Estrogen and progesterone levels impact immune regulation and can alter the balance between pro-inflammatory and anti-inflammatory cytokines.
4.7 Epigenetic Factors
Epigenetic mechanisms are considered to result in modulation of individual gene expression and an increased likelihood of the disease; studies highlight the significant role of epigenetic factors in the etiology and pathogenesis of psoriasis. Epigenetic mechanisms in psoriasis include DNA methylation, histone modifications, and non-coding RNAs.
5. Dietary Patterns Studied in Psoriasis
5.1 Mediterranean Diet
The Mediterranean diet (MeD) is a plant-forward diet emphasizing fruits, vegetables, whole grains, and healthy fats; extra virgin olive oil is a central part of the diet, in addition to fish/seafood rich in omega-3 polyunsaturated fatty acids (PUFAs). Foods like red meat, dairy, and processed sweets are limited. Certain diets, such as low-calorie diets for obese patients, gluten-free diets for patients with comorbid celiac disease, and the Mediterranean diet, may have benefits for psoriasis patients. Given the anti-inflammatory effects and cardiovascular benefits of the Mediterranean diet, it is considered a good option for patients with psoriasis.
Evidence for the Mediterranean diet in psoriasis is predominantly observational. Cross-sectional studies (e.g., Korovesi et al., 2019, as cited in published reviews) have reported that adherence to the Mediterranean diet is independently associated with psoriasis risk, severity, and quality of life, though well-controlled intervention trials are lacking and the evidence base remains preliminary.
5.2 Low-Calorie and Weight-Reduction Diets
A low-calorie diet is often recommended for individuals who are overweight or obese, and there is a strong association between obesity and psoriatic disease activity and progression. The beneficial effect of low-calorie diets (LCD) on psoriasis severity in subjects with obesity is supported in recent systematic reviews. From the available literature, only weight reduction with hypocaloric diets in overweight or obese patients could be strongly recommended by reviewers; they also recommended a gluten-free diet in those who test positive for serologic markers of gluten sensitivity (IgG tissue transglutaminase and IgA endomysial antibody), and weakly recommended vitamin D supplementation in those with psoriatic arthritis (but not psoriasis only).
5.3 Gluten-Free Diet and Celiac Disease
The possible association between psoriasis and celiac disease has long been observed, but epidemiologic studies attempting to characterize this association have yielded inconclusive results. A positive correlation between celiac disease antibody positivity and severity of psoriasis or psoriatic arthritis — not necessarily corresponding to a biopsy-confirmed diagnosis of celiac disease — was observed, suggesting that psoriasis may be associated with gluten sensitivity but not necessarily with gluten enteropathy. Studies evaluating anti-gliadin antibody (AGA)-positive and AGA-negative patients with psoriasis after a 3-month gluten-free diet, followed by resumption of the normal diet for the same time period, demonstrated a statistically significant reduction in the mean PASI score only in AGA-positive patients with elevated AGA levels. For patients with a diagnosis of celiac disease or seropositivity of IgA or IgG antigliadin antibodies, a gluten-free diet could be beneficial in reducing psoriasis severity. The evidence does not support a gluten-free diet for the general psoriasis population in the absence of seropositivity or confirmed celiac disease.
5.4 Dietary Patterns and Potential Triggers
A high-fiber diet is associated with milder symptoms, whereas the increased consumption of red meat is associated with more severe disease manifestations. Sugar, alcohol, nightshade (Solanaceae) vegetables, and gluten are the most common foods reported to trigger or exacerbate psoriasis symptoms. These associations are largely based on observational data and patient-reported outcomes; controlled trials are sparse.
6. Nutrients Studied in Relation to Psoriasis
6.1 Omega-3 Fatty Acids (Fish Oil)
Among nutritional supplements studied in psoriasis, the evidence of benefit is highest for fish oils; for other supplements, there is a need for additional large, randomized clinical trials to establish evidence of efficacy.
Dietary omega-3 (n-3) fatty acids have a variety of anti-inflammatory and immune-modulating effects; a variety of biologic effects of EPA and DHA have been demonstrated from feeding studies with fish or fish oil supplements in humans and animals. Previous studies have suggested a benefit for patients with plaque psoriasis when omega-3 fatty acids are added to topical treatment; a small controlled study evaluated the efficacy of a nutritional complement rich in omega-3 fatty acids in patients with mild or moderate plaque psoriasis. The main efficacy endpoints were the PASI, Nail Psoriasis Severity Index (NAPSI), and DLQI; a clear and significant improvement was observed in all efficacy endpoints in both groups between the baseline visit and the end visit.
Multiple early double-blind, randomized, placebo-controlled trials (including Mayser et al., 1998, referenced in published reviews) evaluated intravenous omega-3 fatty acid-based lipid infusion in chronic plaque psoriasis and acute guttate psoriasis, finding improvements in clinical manifestations. However, overall evidence remains heterogeneous, studies are generally small, and the magnitude and durability of effects from oral supplementation require further investigation.
6.2 Vitamin D
Recent evidence has suggested an additional role of vitamin D in the pathogenesis of several inflammatory skin diseases, including psoriasis; an association between low levels of vitamin D and psoriasis has been described. Vitamin D also participates in keratinocyte proliferation and maturation. Nevertheless, the potential value of vitamin D supplementation for psoriasis is still under debate.
Researchers evaluating several nutritional strategies for patients with psoriasis — including hypocaloric diet, vitamin D, fish oil, selenium, and zinc supplementation — concluded that vitamin D supplementation in patients with psoriasis who are deficient in the vitamin might aid in preventing psoriasis-related comorbidities. As noted in the National Psoriasis Foundation's dietary recommendations, vitamin D supplementation is only weakly recommended, and specifically for those with psoriatic arthritis, not psoriasis alone, reflecting limited high-quality evidence for systemic oral supplementation in skin-only disease.
6.3 Selenium
Deficiency in specific vitamins and minerals, such as vitamin D, vitamin A, zinc, and selenium, is associated with the occurrence and development of psoriasis. The ability of dietary antioxidants — such as omega-3 polyunsaturated fatty acids from fish oil, some vitamins (A, E, and C), and oligoelements including iron, copper, manganese, zinc, and selenium — to decrease oxidative stress and the production of reactive oxygen species may be of particular relevance in chronic systemic inflammatory diseases like psoriasis. However, patients often inquire about selenium supplementation; for this and other supplements beyond fish oil, there is a need for additional large, randomized clinical trials to establish evidence of efficacy.
6.4 Zinc
It is believed that certain vitamins (e.g., A, E, and C) and oligoelements (e.g., iron, copper, manganese, zinc, and selenium) are antioxidants, leading to a reduction in oxidative stress and decreased production of reactive oxygen species. Zinc has been studied for its roles in wound healing and immune modulation, and deficiency has been reported in psoriasis populations, though robust interventional evidence from large, well-controlled clinical trials is lacking.
6.5 Vitamin B12
Supplements including vitamin B12, vitamin D, general multivitamins, and folic acid are popular across studies in different nations; patients often take supplements not only because of the perceived benefits, but also because of inadequate treatment response to medication. Evidence for oral vitamin B12 in psoriasis is limited primarily to small, uncontrolled studies; topical cobalamin (vitamin B12) preparations have been evaluated in a small number of clinical trials with modest results, and further rigorous research is needed.
7. Herbs and Natural Ingredients Studied in Psoriasis
7.1 Mahonia aquifolium (Oregon Grape)
Traditional use: The barberry Mahonia aquifolium is a shrub indigenous to North America. It was used for centuries by Native Americans to treat psoriasis. Tinctures and ointments from Mahonia bark are available as traditional drugs in North America and Europe.
Scientific evidence: The healing effect of Mahonia aquifolium against psoriasis is attributed to berberine, an alkaloid found in the plant's extract; the crude extract's main components include bisbenzylisoquinoline alkaloids and protoberberine. The first group inhibited the production of IL-1, T cells, and TNF-α. A randomized, placebo-controlled, double-blind study in 200 psoriasis patients demonstrated the efficacy and safety of a 10% Mahonia ointment in the treatment of psoriasis; application was done twice daily for 12 weeks (Level of Evidence A). In a systematic review of topical botanical agents for psoriasis, the most highly studied and most efficacious topical botanical therapeutics were Mahonia aquifolium, indigo naturalis, aloe vera, and, to a lesser degree, capsaicin. In a 2025 systematic review, the most effective remedies based on current evidence were Mahonia aquifolium and Indigo naturalis, both of which were supported by multiple studies demonstrating statistically significant reductions in psoriasis severity. Overall, evidence is promising but the total number of high-quality trials is still limited.
7.2 Indigo Naturalis
Traditional use: Indigo naturalis is an important remedy in Traditional Chinese Medicine (TCM). It is a blue powder obtained from the plant Baphicacanthus cusia by grinding, fermentation, and addition of lime.
Scientific evidence: In a randomized, placebo-controlled study, 42 patients suffering from chronic plaque psoriasis were treated once daily with a 10% indigo-containing ointment for 12 weeks; indigo extract (200 µg/g) reduced the PASI by 70%, and indigo extract (50 µg/g) reduced the PASI by 50%. Punch biopsies obtained before treatment and after 8 weeks of treatment revealed a normalization of skin morphology and downregulation of the pro-inflammatory key cytokine in psoriasis, IL-17. The indigo naturalis therapy alleviated symptoms by 81%, whereas the placebo therapy only reduced symptoms by 26%. All studies with indigo extract were performed on Asian patients; whether the effect of Indigo naturalis is comparable in Caucasians cannot currently be assessed. The most commonly reported adverse effects were local skin irritation, erythema, pruritus, burning, and pain; however, the overall evidence for these therapeutics remains limited in quantity and quality.
7.3 Aloe Vera (Aloe barbadensis)
Traditional use: Aloe vera gel has been used in traditional medicine across many cultures, including Ayurveda and traditional African medicine, for its soothing and anti-inflammatory properties on skin conditions.
Scientific evidence: Evidence supports Mahonia aquifolium, Indigo naturalis, and Aloe vera for psoriasis care. Among the most highly studied and most efficacious topical botanical therapeutics were Mahonia aquifolium, Indigo naturalis, aloe vera, and, to a lesser degree, capsaicin. Aloe vera, turmeric, chamomile, pumpkin seed oleogel, St. John's wort, and boswellia-based preparations also showed some beneficial effects in individual studies. Evidence for aloe vera is weaker and less consistent than for Mahonia aquifolium or Indigo naturalis; available trials are generally small and methodologically heterogeneous.
7.4 Curcumin (from Curcuma longa, Turmeric)
Traditional use: Turmeric plays an important role in TCM and in Ayurvedic medicine. It has been used for centuries in South Asian and East Asian traditions as a topical and oral remedy for inflammatory skin conditions.
Scientific evidence: In vitro, turmeric and its major active ingredient curcumin display anti-inflammatory, antimicrobial, and anti-oxidative properties. Curcumin has been demonstrated to be a TNF-α blocker. Oral turmeric showed promise in one study, particularly when combined with conventional topical steroids. Promising results have been seen with turmeric, St. John's wort, boswellia, and chamomile treatments in individual studies. The overall evidence from human clinical trials for curcumin in psoriasis remains preliminary. Bioavailability of standard curcumin preparations is poor, and most positive results come from small, often uncontrolled studies. Large, high-quality RCTs are lacking.
7.5 Capsaicin (Capsicum frutescens)
Traditional use: Capsaicin from chili peppers has a history of topical use across Central American and Asian folk medicine for pain relief and skin inflammation.
Scientific evidence: The anti-psoriatic effect of topical herbal therapies — including Aloe vera, Capsicum frutescens (the alkaloid capsaicin), Curcuma longa (curcumin), Hypericum perforatum, Indigo naturalis, and Mahonia aquifolium — has recently been evaluated in vivo. Capsaicin's proposed mechanism involves depletion of substance P from sensory nerve terminals, which may reduce neurogenic inflammation. Clinical evidence is limited to small studies; its use is primarily noted for reduction of pruritus rather than plaque clearance.
7.6 St. John's Wort (Hypericum perforatum)
Traditional use: Hypericum perforatum has been used in European herbal traditions for centuries for wound healing, inflammation, and various skin disorders.
Scientific evidence: Promising results have been seen with St. John's wort treatments in individual studies. Evidence is currently limited to a small number of controlled trials examining topical preparations; the evidence is insufficient for firm conclusions and further research is needed.
7.7 Boswellia (Boswellia serrata)
Traditional use: Boswellia (Indian frankincense) has been used in Ayurvedic medicine for inflammatory conditions including skin disease. Its resin was applied topically and taken orally for its reputed anti-inflammatory properties.
Scientific evidence: Boswellia-based preparations showed some beneficial effects in individual studies. The active compounds (boswellic acids) are proposed to inhibit leukotriene synthesis. Human clinical trial data specifically for psoriasis is limited; most available evidence is from small studies or extrapolated from research in related inflammatory conditions.
8. The Gut-Skin Axis and Probiotics
Recent research has found a link between psoriasis, inflammation, and gut microbiota dysbiosis, and has suggested that probiotics and prebiotics may provide benefits to patients. In animal models, oral Lactobacillus administration reduced psoriasiform inflammation by promoting Foxp3+ regulatory T-cell infiltration and limiting keratinocyte apoptosis.
Human studies show similar effects: several randomized controlled trials (RCTs) demonstrated significant improvement in PASI and DLQI among participants receiving probiotics compared with placebo. These improvements were often associated with lower inflammatory marker levels and increased gut microbial diversity. Probiotics also strengthen intestinal tight junctions, reducing permeability and systemic inflammation.
Current clinical evidence focuses on immunocompetent individuals, and none of the included studies evaluated probiotic effects specifically in immunocompromised patients; therefore, their safety and immunologic impact in such populations remain uncertain. Overall, while the mechanistic rationale for the gut-skin axis in psoriasis is supported by emerging evidence, the clinical evidence for probiotics is preliminary and further large, well-controlled trials are needed.
9. Dietary and Lifestyle Factors: Summary of Authoritative Guidance
9.1 Physical Activity
Psoriatic patients are recommended to engage in regular physical activity, to avoid alcohol intake, and to consume fish rich in omega-3 polyunsaturated fatty acids, as well as fruit and vegetables. Dietary habits, body weight, smoking, alcohol use, stress, and physical activity all contribute to systemic inflammation and immune activity — core mechanisms in psoriasis pathogenesis.
9.2 Alcohol Reduction and Smoking Cessation
NICE guidelines for psoriasis assessment and management mention reducing alcohol intake and losing weight, but only as modifiable risk factors for associated comorbidities. Both smoking and alcohol are well-documented as associated with increased psoriasis risk and severity in the epidemiological literature, but the evidence base for their direct, reversible impact on skin disease severity (as opposed to comorbidities) requires further controlled study.
9.3 Evidence Strength: Overall Assessment
Supplements in general do not show strong evidence of benefit for psoriasis, though more studies are required given the heterogeneity of these trials. Based on low-quality data, select foods, nutrients, and dietary patterns may affect psoriasis. For patients with psoriatic arthritis, vitamin D supplementation and dietary weight reduction with a hypocaloric diet in overweight and obese patients are weakly recommended. Dietary interventions should always be used in conjunction with standard medical therapies for psoriasis and psoriatic arthritis.
The literature addresses a large number of studies regarding botanicals for the treatment of psoriasis; while most agents appear to be safe, further research is necessary before topical botanical agents can be consistently recommended to patients. Herbal therapies present a diverse array of options for psoriasis management, but further research is essential to elucidate their safety profile and true effectiveness.
References
Go back