The effects of dietary supplementation with fish oil in patients with psoriasis

Herring roe oil in treatment of psoriasis - influence on immune cells and cytokine network

Background

Psoriasis is a chronic immune-mediated skin disease with systemic inflammation and comorbidities. Although the disease severity may vary over time, many patients suffer from mild to moderate disease. Often local treatment will be sufficient to control the symptoms, but they may have several side effects. ω-3 polyunsaturated fatty acids have shown promising results in clinical trials with mild-to-moderate psoriasis.

Methods

We explored the impact of phospholipid bound docosahexaenoic acid and eicosapentaenoic acid in a 3:1 ratio on immune cells and cytokine networks in peripheral blood of patients with psoriasis. We investigated the inter-relation of plasma cytokine levels and disease severity in 58 patients, and explored the status of circulating immune cell activity in 18 patients with non-severe psoriasis before and during herring roe oil supplementation. Plasma concentration of 22 cytokines was measured by Luminex technology and circulating immune cells were analyzed by multicolor flow cytometry.

Results

CCL2 levels decreased over time, and IFN-γR1 increased, possibly related to the action of ω-3 polyunsaturated fatty acids. We observed a shift from naïve to effector CD4+ T cells and decreases of CD38 expression on CD4+ and CD8+ T cells, CD56bright NK cells and CD14+CD16- classical monocytes.

Conclusions

These findings support the beneficial effect of herring roe oil supplementation.

Metabolic Disorders and Psoriasis: Exploring the Role of Nutritional Interventions

(1) Background: Psoriasis is a chronic autoimmune disease with a close relationship with metabolic diseases such as obesity, diabetes, and dyslipidemia. The aim of this review was to identify the relationship between psoriasis, metabolic diseases, and dietetic therapies. According to recent findings, there is a strong association between psoriasis and obesity as well as vitamin D and micronutrient deficiencies. (2) Methods: This review was conducted via PubMed, aiming to search for studies involving psoriasis linked with metabolic disorders or with nutritional treatments. (3) Results: Our review shows that a healthy lifestyle can positively influence the course of the disease. The maintaining of a proper body weight together with physical activity and good nutritional choices are associated with an improvement in psoriasis severity. A Mediterranean diet rich in fiber, vitamins, and polyphenols may indeed be a strategy for controlling psoriasis symptoms. The effectiveness of this diet lies not only in its anti-inflammatory power, but also in its ability to favorably influence the intestinal microbiota and counteract dysbiosis, which is a risk factor for many autoimmune diseases. (4) Conclusions: In synergy with standard therapy, the adoption of an appropriate diet can be recommended to improve the clinical expression of psoriasis and reduce the incidence of comorbidities.

Dietary Intervention and Supplements in the Management of Psoriasis: Current Perspectives

Nutrition is a complex topic encompassing diet and a variety of supplements including vitamins, fish oil, herbal products, and probiotics. Patients with psoriasis display high interest in understanding the potential impact of nutritional modifications on their psoriasis. In this review, we examine the evidence for nutritional interventions in psoriasis and summarize important concepts. We found that 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. Supplements in general do not show strong evidence of benefit, though more studies are required given the heterogeneity of these trials. Finally, the gut microbiome has drawn considerable interest in recent years, with specific probiotics showing promising results for psoriasis patients and warranting further exploration.

Association Between Daily Dietary Eicosatetraenoic Acid Intake and the Lower Risk of Psoriasis in American Adults

Purpose

Unlike eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the relationship between eicosatetraenoic acid (ETA) and psoriasis remains unclear. Therefore, We performed a cross-sectional study in the general American population to investigate the association between daily dietary ETA, EPA, and DHA intake and the risk of psoriasis.

Participants and Methods

This study applied data from the National Health and Nutrition Examination Survey (NHANES) 2003-2006 and 2009-2014. Dietary n3 polyunsaturated fatty acids (PUFA) were calculated based on two 24-hour dietary recall interviews. We defined psoriasis by responding to the question "Have you ever been told by a doctor or other health care professional that you had psoriasis?". Multivariable logistic regression analysis, trend tests, subgroup analysis, and interaction tests were used to evaluate the associations of ETA, EPA, and DHA intake with the risk of psoriasis, respectively.

Results

A total of 15,733 participants were included in this study. In our optimal multivariate-adjusted model, the odds ratio (OR) with 95% confidence interval (CI) of psoriasis were 0.30 (0.12, 0.88), 1.92 (0.78, 4.74), 1.28 (0.72, 2.27) for daily dietary ETA, EPA, and DHA intake, respectively. Trend tests showed a dose-effect relationship between daily dietary ETA intake and the lower risk of psoriasis. Subgroup analysis and tests for interaction showed that the association was stable in different subgroups.

Conclusion

Our study revealed that there might be a dose-effect association of daily dietary ETA intake with the lower risk of psoriasis in American adults.

Daily Lifestyle and Inflammatory Skin Diseases

Throughout life, it is necessary to adapt to the Earth’s environment in order to survive. A typical example of this is that the daily Earth cycle is different from the circadian rhythm in human beings; however, the ability to adapt to the Earth cycle has contributed to the development of human evolution. In addition, humans can consume and digest Earth-derived foods and use luxury materials for nutrition and enrichment of their lives, as an adaptation to the Earth’s environment. Recent studies have shown that daily lifestyles are closely related to human health; however, less attention has been paid to the fact that obesity due to excessive energy intake, smoking, and alcohol consumption contributes to the development of inflammatory skin diseases. Gluten or wheat protein, smoking and alcohol, sleep disturbance, and obesity drive the helper T (Th)1/Th2/Th17 immune response, whereas dietary fiber and omega-3 fatty acids negatively regulate inflammatory cytokine production. In this review, we have focused on daily lifestyles and the mechanisms involved in the pathogenesis of inflammatory skin diseases.

The Effect of Antioxidant and Anti-Inflammatory Capacity of Diet on Psoriasis and Psoriatic Arthritis Phenotype: Nutrition as Therapeutic Tool?

Chronic inflammation and increased oxidative stress are contributing factors to many non-communicable diseases. A growing body of evidence indicates that dietary nutrients can activate the immune system and may lead to the overproduction of pro-inflammatory cytokines. Fatty acids as macronutrients are key players for immunomodulation, with n-3 polyunsaturated fatty acids having the most beneficial effect, while polyphenols and carotenoids seem to be the most promising antioxidants. Psoriasis is a chronic, immune-mediated inflammatory disease with multifactorial etiology. Obesity is a major risk factor for psoriasis, which leads to worse clinical outcomes. Weight loss interventions and, generally, dietary regimens such as gluten-free and Mediterranean diet or supplement use may potentially improve psoriasis’ natural course and response to therapy. However, data about more sophisticated nutritional patterns, such as ketogenic, very low-carb or specific macro- and micro-nutrient substitution, are scarce. This review aims to present the effect of strictly structured dietary nutrients, that are known to affect glucose/lipid metabolism and insulin responses, on chronic inflammation and immunity, and to discuss the utility of nutritional regimens as possible therapeutic tools for psoriasis and psoriatic arthritis.

Efficacy of fish oil and its components in the management of psoriasis: a systematic review of 18 randomized controlled trials

Context

Fish oil and omega-3 polyunsaturated fatty acids (ω-3 PUFAs) have anti-inflammatory properties, but their effect on psoriasis and its comorbidities remains inconclusive.

Objective

The aim of this quantitative systematic review was to evaluate the efficacy and safety of fish oil and its components in the treatment of psoriasis and its comorbidities.

Data Sources

PubMed, Embase, Cochrane Central Register of Controlled Trials, China Network Knowledge Infrastructure, China Science and Technology Journal Database, and Wanfang databases were searched from inception to March 30, 2019.

Study Selection

Randomized controlled trials were eligible for inclusion if they measured the effect of fish oil and its components in the treatment of patients with psoriasis.

Data Extraction

Eighteen randomized controlled trials involving 927 study participants were included.

Results

Monotherapy with fish oil or ω-3 PUFAs had no effect on the Psoriasis Area and Severity Index (PASI) score (P = 0.47), lesion area (P = 0.34), or pruritus (P = 0.62). Fish oil or ω-3 PUFAs combined with conventional treatments, however, resulted in a decreased PASI score (mean difference [MD], −3.92; 95%CI, −6.15 to −1.69; P = 0.0006) and lesion area (MD, −30.00; 95%CI, −33.82 to −26.18; P < 0.0001). Safety evaluation suggested no between-group differences. Fish oil and its components reduced certain risk factors for obesity, cardiovascular disease, and metabolic disease in patients with psoriasis and also regulated several inflammatory mediators.

Conclusions

Overall, when combined with conventional treatments, fish oil and its components may have beneficial effects on psoriasis and its comorbidities, including obesity, cardiovascular disease, and metabolic disease.

Systematic Review Registration

PROSPERO registration number CRD42019128631.

Omega-3 Versus Omega-6 Polyunsaturated Fatty Acids in the Prevention and Treatment of Inflammatory Skin Diseases

Omega-3 (ω-3) and omega-6 (ω-6) polyunsaturated fatty acids (PUFAs) are nowadays desirable components of oils with special dietary and functional properties. Their therapeutic and health-promoting effects have already been established in various chronic inflammatory and autoimmune diseases through various mechanisms, including modifications in cell membrane lipid composition, gene expression, cellular metabolism, and signal transduction. The application of ω-3 and ω-6 PUFAs in most common skin diseases has been examined in numerous studies, but their results and conclusions were mostly opposing and inconclusive. It seems that combined ω-6, gamma-linolenic acid (GLA), and ω-3 long-chain PUFAs supplementation exhibits the highest potential in diminishing inflammatory processes, which could be beneficial for the management of inflammatory skin diseases, such as atopic dermatitis, psoriasis, and acne. Due to significant population and individually-based genetic variations that impact PUFAs metabolism and associated metabolites, gene expression, and subsequent inflammatory responses, at this point, we could not recommend strict dietary and supplementation strategies for disease prevention and treatment that will be appropriate for all. Well-balanced nutrition and additional anti-inflammatory PUFA-based supplementation should be encouraged in a targeted manner for individuals in need to provide better management of skin diseases but, most importantly, to maintain and improve overall skin health.

[Daily Life Style and Psoriasis]

Skin is an important organ that is located on the outermost layer of the human body, and serves as a defense barrier against external stimulation. Daily life style, including diet, exercise, and sleep, is a fundamental behavior of humans, and it has recently been reported that daily life style has a strong relationship with the inflammatory condition of skin diseases. This relationship has been examined by various approaches, including epidemiological investigations. Psoriasis is one inflammatory skin disease and is especially closely related with daily life style, such as diet, sleep, smoking and alcohol consumption. The interleukin (IL)-23/IL-17 axis plays an important role in the pathogenesis of psoriasis, and daily life style is considered to affect this cascade, leading to exacerbation of the inflammatory condition. In this review article, we report how daily life style affects psoriasis.

Management of psoriasis with nutraceuticals: An update

Psoriasis is a chronic skin disorder that speeds up the life cycle of skin cells, typically on the surface of the skin. Additional skin cells form thick scales and red fixes which are awfully itchy and sometimes painful. Although there are many therapeutic systems available to get symptomatic relief, unfortunately replete cure for psoriasis is not yet reported. Moreover, poor treatment outcomes as well as high toxicity profile of drugs makes these therapies more inconvenient to treat psoriasis. In search of alternative and complementary therapy for this disease, the focus has been shifted to nutraceuticals, few of them were reported since ages. It includes vitamins, herbal extracts, phytochemicals and dietary supplements. In this review, the attempt has been made to highlight key nutraceuticals for better management of psoriasis. Supplementation of appropriate nutraceutical may improve the quality of patient's life and have positive impact on overall state of disease.

Dietary Behaviors in Psoriasis: Patient-Reported Outcomes from a U.S. National Survey

INTRODUCTION

Psoriasis patients demonstrate high interest in the role of diet on their skin condition. However, data are lacking to describe dietary interventions among psoriasis patients and associated outcomes. This study aims to identify common dietary habits, interventions and perceptions among patients with psoriasis, and to examine patient-reported skin outcomes in response to these interventions.

METHODS

We administered a 61-question survey to the National Psoriasis Foundation membership asking psoriasis patients about dietary habits, modifications, skin responses, and perceptions.

RESULTS

A total of 1206 psoriasis patients responded to the survey. Compared to age- and sex-matched controls, psoriasis patients consumed significantly less sugar, whole grain fiber, dairy, and calcium (p < 0.001), while consuming more fruits, vegetables, and legumes (p < 0.01). Eighty-six percent of respondents reported use of a dietary modification. The percentage of patients reporting skin improvement was greatest after reducing alcohol (53.8%), gluten (53.4%), nightshades (52.1%), and after adding fish oil/omega-3 (44.6%), vegetables (42.5%), and oral vitamin D (41%). Specific diets with the most patients reporting a favorable skin response were Pagano (72.2%), vegan (70%), and Paleolithic (68.9%). Additionally, 41.8% of psoriasis respondents reported that a motivation for attempting dietary changes was to improve overall health.

CONCLUSION

This national survey is among the first to report the dietary behaviors of patients with psoriasis. The data provided from this large cohort may benefit patients and clinicians as they discuss the role of diet in managing both psoriasis and associated cardiometabolic comorbidities.

Diet in dermatology: Part II. Melanoma, chronic urticaria, and psoriasis

The roles of dietary factors in aggravating, preventing, or treating skin diseases are common questions encountered in dermatology practice. Part II of this two-part series reviews dietary modifications that can potentially be utilized in the management of melanoma, chronic urticaria, and psoriasis patients. Specifically, we examine the effect of alcohol consumption and supplementation with vitamins D and E, polyunsaturated fatty acids, selenium, green tea, resveratrol, and lycopene on melanoma risk. The relationships between chronic urticaria symptoms and dietary pseudoallergens, gluten, and vitamin D are analyzed. We explore weight loss, reduced alcohol consumption, and gluten avoidance as means of reducing psoriasis-associated morbidity, as well as the possible utility of supplementation with polyunsaturated fatty acids, folic acid, vitamin D, and antioxidants. With proper knowledge of the role of diet in these cutaneous disease processes, dermatologists can better answer patient inquiries and consider implementation of dietary modifications as adjuncts to other treatments and preventative measures.

Diet and psoriasis, part III: role of nutritional supplements

Patients with psoriasis are increasingly turning to the use of alternative and complementary medicine to manage their psoriasis. Patients often inquire about what dietary supplements may be beneficial, including the use of oral vitamin D, vitamin B12, selenium, and omega-3 fatty acids in fish oils. In this review we examine the extent to which each of these common nutritional interventions has been studied for the treatment of psoriasis. We weighed evidence from both controlled and uncontrolled prospective trials. The evidence of benefit was highest for fish oils. For other supplements, there is need for additional large, randomized clinical trials to establish evidence of efficacy.

Is dietary supplementation more common among adults with psoriasis? Results from the National Health and Nutrition Examination Survey

OBJECTIVES

Individuals with psoriasis are often unsatisfied with traditional medical treatments and may be more likely to use dietary supplements as alternative or complementary treatment. Limited data is available on the prevalence of dietary supplement use amongst individuals with psoriasis in the general population. The aim was to utilize a representative sample of the United States to estimate the prevalence of dietary supplement use among adults self-reporting psoriasis.

DESIGN AND SETTING

Cross-sectional data analysis from the 2009 to 2010 National Health and Nutrition Examination Survey. Dietary supplementation over the past 30 days was ascertained and population weights were used to obtain estimates representative of the general population. Logistic regression was used to determine whether psoriasis was associated with higher odds of supplement use.

RESULTS

This study consisted of 6211 participants aged ≥20 years (representing 219 million Americans). Among the 184 participants reporting psoriasis (representing 6.9 million Americans), 53% reported using at least one dietary supplement, which was not different from participants without psoriasis (49.5%, P=0.416). Participants with psoriasis did not have higher odds of supplement use after adjusting for covariates. Multivitamin/mineral supplements were the most common dietary supplements used by participants with psoriasis (29.6%), and the most common reasons for taking them were to maintain and improve health. Only 12 supplements taken by participants with psoriasis were intended to improve skin health.

CONCLUSIONS

Dietary supplementation over the past 30 days was reported by half of adults with psoriasis amongst the United States general population. Few individuals with psoriasis took dietary supplements specifically to improve skin health.

Diet and healthy ageing 2100: will we globalise local knowledge systems?

Diet and health clearly are linked intrinsically. Today, more than ever food is functionalized and tailor made for specific groups (e.g. athletes, the elderly, and people with specific conditions). Increased life expectancy has resulted in an increase in the quest for diets which allow for a healthy ageing. In looking back 100 years, we try to assess how of our diets will evolve in the next 100 years and how this may be linked to a 'healthier ageing'. Our argument centres around a series of dichotomies which we used to explain the main changes in dietary habits and how this impacts on health--the continuous move from dietary traditions which are local, low in technological input and based on empiricism, to diets which are global, require high technological input and are science-based. The innovations our societies have achieved over the last century have allowed us to improve our diet based on a better scientific understanding of the health benefits of such diets, but this is often not achieved due to commercial considerations. This will require that all sectors of the food industry work towards healthy and economically affordable diets. In addition, there will be a continuous demand by the consumers to ascertain that 'our' foods are not only healthy but also convenient and easy to prepare. Healthy ageing will require us to look at a multitude of aspects of foods, to integrate this knowledge and to apply it in all sectors of food production.

Diet and psoriasis: experimental data and clinical evidence

Psoriasis is considered as a T-cell-mediated inflammatory skin disease which is characterized by hyperproliferation and poor differentiation of epidermal keratinocytes. While susceptibility to psoriasis is inherited, the disease is influenced by environmental factors such as infections and stress. Diet has been suggested to play a role in the aetiology and pathogenesis of psoriasis. Fasting periods, low-energy diets and vegetarian diets improved psoriasis symptoms in some studies, and diets rich in n-3 polyunsaturated fatty acids from fish oil also showed beneficial effects. All these diets modify the polyunsaturated fatty acid metabolism and influence the eicosanoid profile, so that inflammatory processes are suppressed. Some patients with psoriasis show an elevated sensitivity to gluten. In patients with IgA and/or IgG antigliadin antibodies the symptoms have been shown to improve on a gluten-free diet. The active form of vitamin D, 1,25-dihydroxyvitamin D(3), exhibits antiproliferative and immunoregulatory effects via the vitamin D receptor, and thus is successfully used in the topical treatment of psoriasis. In this review, dietary factors which play a role in psoriasis are assessed and their potential benefit is evaluated. Furthermore, the risk of drug-nutrient interactions in psoriasis therapy is discussed.

Effectiveness of kukui nut oil as a topical treatment for psoriasis

BACKGROUND

No cure for psoriasis exists for the 1-3% of the American population who suffer from it; however, anecdotal reports from patients with psoriasis visiting Hawaii who purchased kukui nut oil, claim it helped reduce the severity of their lesions.

OBJECTIVE

This pilot study was a double-blind, placebo-controlled clinical trial to determine the effectiveness of kukui nut oil as a topical treatment for psoriasis.

METHODS

Thirty adult subjects (18-78 year) were recruited from the community for a 12-week randomized, double-blind, placebo-controlled pilot study. Subjects were previously diagnosed with mild, stable plaque psoriasis (less than 15% of total body surface area [TBSA]) and agreed to abstain from other treatments during the course of the study. Following a 4-week washout period the subjects were randomized into a treatment group (15 subjects applying kukui nut oil) or a control group (15 applying the mineral oil placebo). Patients were seen every 2 weeks (seven visits at 0, 2, 4, 6, 8, 10, and 12 weeks) by a dermatological nurse practitioner under the general supervision of a board certified dermatologist. Measurable outcomes included evaluation of one targeted lesion and of the overall severity of their psoriasis using clinical evaluation, Psoriasis Area and Sensitivity Index (PASI), Global Severity of Psoriasis Scale, and photographs. Each patient also evaluated their own lesions daily using the Global Severity of Psoriasis Scale, and noted any side-effects or other treatments used.

RESULTS

Although both groups improved, we found no significant difference between the treatment (kukui nut oil) and the placebo (mineral oil) among the 24 out of 30 subjects (80%) who completed the study. No side-effects or adverse events were reported.

CONCLUSION

Kukui nut oil did not significantly reduce symptoms of psoriasis; however, this was a small pilot study, and the use of this oil cannot be dismissed without using a larger study population of patients with psoriasis.

Vitamin D3?Based Conjugates for Topical Treatment of Psoriasis: Synthesis, Antiproliferative Activity, and Cutaneous Penetration Studies

PURPOSE

The goals of the experiments reported in this paper were to explore skin bioavailability and cell growth inhibitory activity of new vitamin D3-based conjugates studied as a potential drug complex for psoriasis.

METHODS

Conjugation was made between polyunsaturated fatty acids (PUFAs), such as linolenic acid or gamma-linolenic acid, and calcipotriol--a vitamin D3 analogue clinically used for topical treatment of psoriasis. These complexes were prepared by coupling the corresponding fatty acid with calcipotriol in the presence of dicyclohexyl-carbodiimide (DCC) and 4-(dimethylamino)-pyridine (DMAP) to obtain an ester bond.

RESULTS

The conjugates were capable of enhancing the penetration of the vitamin into the skin as well as inhibiting proliferation of keratinocytes in cultures. The antiproliferative activity even increased after simulating the full hydrolysis of the conjugates. In vitro skin penetration studies revealed that the conjugates penetrated into the skin at higher levels relative to calcipotriol alone. It was also demonstrated that the conjugate containing n-3 fatty acid penetrated into the skin at higher levels as compared to the conjugate containing n-6 PUFA. High-performance liquid chromatography analysis has shown that after penetration, a major portion of calcipotriol-PUFA conjugate was first converted mainly into another isomer form, presumably by transesterification, and only then it was hydrolyzed to form apparently high local concentrations of both calcipotriol and PUFA.

CONCLUSIONS

The unique biotransformation that occurred after penetration into the skin indicates that these conjugates are mutual prodrugs that are able to be bioprocessed in the skin and fully converted to the parent therapeutic agents.

n-3 fatty acids in psoriasis

Increased concentrations of free arachidonic acid (AA) and its proinflammatory metabolites have been observed in psoriatic lesions. Replacement of arachidonic acid by alternative precursor polyunsaturated fatty acids (PUFA), especially eicosapentaenoic acid (EPA), which can be metabolized via the same enzymatic pathways as AA, might be a therapeutic option in psoriasis. However the results of studies evaluating the therapeutic benefit of dietary fish oil have been conflicting and not clearly dose-dependent. To overcome the slow kinetics and limited availability of oral supplementation, we have performed three studies to assess the efficacy and safety of an intravenously administered fish oil derived lipid emulsion on different forms of psoriasis. Patients received daily infusions of either an n-3 fatty acid-based lipid emulsion (Omegaven) or a conventional n-6 lipid emulsion (Lipoven) in different time and dose regimens. In addition to an overall assessment of the clinical course of psoriasis, EPA- and AA-derived neutrophil 5-lipoxygenase (LO)--products, thromboxane (TX) B2/B3, PAF and plasma free fatty acids were investigated. Treatment with n-3 fatty acids resulted in a considerably higher response rate than infusion of n-6 lipids. A more than 10-fold increase in neutrophil EPA-derived 5-LO product formation was noted in the n-3 group, accompanied by a rapid increase in plasma-free EPA within the first days. In conclusion, intravenous n-3-fatty acid administration causes reduction of psoriasis, which may be related to changes in inflammatory eicosanoid generation. The rapidity of the response to intravenous n-3 lipids exceeds by orders of magnitude the hitherto reported kinetics of improvement of psoriatic lesions upon use of oral supplementation.

Systemic aspects of psoriasis. An integrative model based on intestinal etiology

Psoriasis can best be understood from a multifactorial approach that recognizes the systemic aspects of the disorder. Among the various factors thought to be involved in the etiology and pathogenesis of psoriasis, bowel pathology has assumed a noteworthy position in the literature. This article reviews the psoriasis/bowel connection with regard to abnormal bowel structure and physiology in psoriasis patients. Clinical implications of bowel involvement in psoriasis are discussed within the framework of an integrative medicine model that emphasizes natural therapeutics for addressing the systemic aspects of the illness.

Metabolism of polyunsaturated fatty acids by skin epidermal enzymes: generation of antiinflammatory and antiproliferative metabolites

In the skin epidermis, the metabolism of polyunsaturated fatty acids (PUFAs) is highly active. Dietary deficiency of linoleic acid (LA), the major 18-carbon n-6 PUFA in normal epidermis, results in a characteristic scaly skin disorder and excessive epidermal water loss. Because of the inability of normal skin epidermis to desaturate LA to gamma-linolenic acid, it is transformed by epidermal 15-lipoxygenase to mainly 13-hydroxyoctadecadienoic acid, which functionally exerts antiproliferative properties in the tissue. In contrast, compared with LA, arachidonic acid (AA) is a relatively minor 20-carbon n-6 PUFA in the skin and is metabolized via the cyclooxygenase pathway, predominantly to the prostaglandins E(2), F(2)(alpha), and D(2). AA is also metabolized via the 15-lipoxygenase pathway, predominantly to 15-hydroxyeicosatetraenoic acid. At low concentrations, the prostaglandins function to modulate normal skin physiologic processes, whereas at high concentrations they induce inflammatory processes. PUFAs derived from other dietary oils are also transformed mainly into monohydroxy fatty acids. For instance, epidermal 15-lipoxygenase transforms dihomo-gamma-linolenic acid (20:3n-6) to 15-hydroxyeicosatrienoic acid, eicosapentaenoic acid (20:5n-3) to 15-hydroxyeicosapentaenoic acid, and docosahexaenoic acid (22:6n-3) to 17-hydroxydocosahexaenoic acid, respectively. These monohydroxy acids exhibit antiinflammatory properties in vitro. Thus, supplementation of diets with appropriate purified vegetable oils, fish oil, or both may generate local cutaneous antiinflammatory and antiproliferative metabolites which could serve as less toxic in vivo monotherapies or as adjuncts to standard therapeutic regimens for the management of inflammatory skin disorders.

A review of the epidemiology of psoriasis vulgaris in the community

Standard diagnostic criteria for epidemiological studies of psoriasis are currently lacking. In their absence, clinical examination and diagnosis of psoriasis by dermatologists provides the gold standard to underpin epidemiological research in psoriasis. The methods of data collection used most frequently include cross-sectional studies, case-control studies, cohort studies, and surveys of hospital and private practice attendance. Estimates of psoriasis prevalence made in cross-sectional studies employing clinical examinations as the survey instrument have ranged from 0.3 to 2.5%. Psoriasis incidence has been estimated at 60.4 per 100,000 person years in one cohort study. Several factors have been identified as being associated either with causation of psoriasis or with triggering exacerbations or remissions, including genetic determinants, racial and regional variation, injury and infection, cigarette smoking, alcohol, diet and other diseases.

Dietary fish oil diminishes lymphocyte adhesion to macrophage and endothelial cell monolayers

To further investigate the immunomodulatory effects of dietary lipids, rats were fed on a low-fat diet or on high-fat diets that contained hydrogenated coconut, olive, safflower, evening primrose or fish oil as the principal fat source. The fish oil diet decreased the level of expression of CD2, CD11a, CD18 and CD44 on the surface of freshly prepared lymphocytes and of CD2, CD11a, CD18, CD54 (intercellular adhesion molecule-1; ICAM-1) and CD62L (L-selectin) on the surface of concanavalin A (Con A)-stimulated lymphocytes. The olive oil diet also resulted in decreased expression of some adhesion molecules. The fish or olive oil diets, and to a lesser extent the safflower or evening primrose oil diets, decreased the adhesion of both freshly prepared and Con A-stimulated lymphocytes to macrophage monolayers. The fish oil diet, and to a lesser extent the olive or evening primrose oil diets, reduced the ability of Con A-stimulated lymphocytes to adhere to untreated endothelial cells. Furthermore, the fish oil diet resulted in a 50% reduction in Con A-stimulated lymphocyte adhesion to tumour necrosis factor-alpha (TNF-alpha)-stimulated endothelial cells. This study demonstrates that dietary lipids affect the expression of functionally important adhesion molecules on the surface of lymphocytes. Furthermore, this study suggests that such diet-induced effects on adhesion molecule expression might alter the ability of lymphocytes to bind to macrophages and to endothelial cells. Of the diets studied fish oil causes the most significant effects. The results of this study suggest that a reduction in cellular infiltration may partly explain the protective effect of a fish-oil-rich diet against the development of inflammatory and cardiovascular diseases.

Glucosamine for psoriasis?

Amphiregulin and transforming growth factor-alpha, agonists for the epidermal growth factor receptor, are the major autocrine growth factors for cultured keratinocytes, and their substantial overexpression in psoriatic lesions suggests that they are crucial to the basal hyperplasia that characterizes psoriasis. Amphiregulin binds to heparin and related highly sulfated polysaccharides, and exogenous heparin blocks its growth factor activity, rationalizing previous reports that psoriasis responds to heparin therapy. Differentiating keratinocytes produce increased amounts of protein-bound as well as free-chain heparan sulfates, which may function physiologically as amphiregulin antagonists. By promoting keratinocyte synthesis of these heparan sulfates, glucosamine administration may inhibit amphiregulin function and thus provide therapeutic benefit in psoriasis. Concurrent ingestion of fish oil, by impeding the excessive activation of protein kinase C, may decrease keratinocyte production of amphiregulin and other autocrine growth factors, thus complementing the postulated benefits of glucosamine.

Effect of degree of unsaturation in dietary fatty acids on arachidonic acid mobilization by peritoneal macrophages

Cells from rats fed with a tripalmitin diet showed a depletion of phospholipid arachidonate and n-3 fatty acids such as eicosapentaenoic and docosahexaenoic acids (EPA and DHA). In rats fed fish oil diet, a significant reduction in arachidonic acid (AA) content was observed whereas EPA and DHA were incorporated into membranes lipids. These changes in lipid composition of membranes did not affect cellular adherence, phagocytic capability, or [3H]AA incorporation. However, both tripalmitin and fish oil diets induced a decrease in [3H]AA mobilization stimulated by 4 beta-phorbol-12-myristate 13-acetate, A23187, or opsonized-zymosan in rat peritoneal macrophages. These results demonstrate that the antiinflammatory effects of essential fatty acids deficiency or n-3 enrichment diets may be associated with a decreased AA mobilization in resident rat peritoneal macrophages treated with proinflammatory agents.

The significance of polyunsaturated fatty acids in cutaneous biology

The skin epidermis displays a highly active metabolism of polyunsaturated fatty acids (PUFA). Dietary deficiency of linoleic acid (LA) and 18-carbon (n-6) PUFA results in characteristic scaly skin disorder and excessive epidermal water loss. Arachidonic acid, a 20-carbon (n-6) PUFA is metabolized via the cyclooxygenase pathway into predominantly prostaglandin E2 (PGE2) PGF2 alpha, and PGD2 and via the lipoxygenase pathway into predominantly 15-hydroxyeicosatetraenoic acid (15-HETE). The prostaglandins modulate normal skin physiological processes at low concentrations and inflammatory reactions at high concentrations. Similarly, the very active epidermal 15-lipoxygenase transforms dihomogammalinolenic acid (DGLA) into 15-hydroxy eicosatrienoic acid (15-HETrE), eicosapentaenoic acid (EPA) into 15-hydroxyeicosapentaenoic acid (15-HEPE) and docosahexaenoic acid (DHA) into 17-hydroxydocosahexaenoic acid (17-HDoHE), respectively. These monohydroxy acids exhibit anti-inflammatory properties. In contrast, the 18-carbon (n-6) PUFA is transformed into 13-hydroxy-9,11-octadecadienoic acid (13-HODE), which exerts antiproliferative properties in the tissue. Thus, the supplementation of diets with appropriate purified vegetable oils and/or fish oil may generate local cutaneous anti-inflammatory metabolites which could serve as a less toxic in vivo monotherapy or as adjuncts to standard therapeutic regimens for the management of skin inflammatory disorders.

Eicosapentaenoic acid-induced changes in membrane fluidity and cell adhesion molecules in cultured human keratinocytes

The effects of eicosapentaenoic acid (EPA, 20:5n-3) on the lipid dynamics of cultured epidermal keratinocytes and their expression of cell adhesion molecules were investigated, and were compared with those of arachidonic acid (AA, 20:4n-6). When keratinocytes were treated with 3 micrograms/ml of EPA or AA for 72 h, these compounds were found to be incorporated into the cells. EPA-induced lipid changes were distinguished by a significant increase in the cellular content of n-3 polyunsaturated fatty acids, whereas AA treatment resulted in an increase in the cellular content of n-6 arachidonic acid. These changes in fatty acid composition were accompanied by an increase in cellular membrane fluidity, which was evaluated by the diffusion coefficient, using the method of fluorescence recovery after photobleaching (FRAP) [from 1.77 +/- 0.34 x 10(-8) cm2/s untreated to 2.23 +/- 0.35 x 10(-8) cm2/s EPA-treated (P < 0.001), and 2.16 +/- 0.35 x 10(-8) cm2/s AA-treated (P < 0.001)]. Intercellular adhesion molecule-1 (ICAM-1) was induced on the keratinocyte membrane in the presence of tumour necrosis factor-alpha and interferon-gamma, and pretreatment with EPA or AA further enhanced the expression, almost to an equal degree, as estimated by flow cytometry (P < 0.05). These results indicate that the modulation of ICAM-1 expression does not seem to be EPA-specific, but is presumably a consequence of increased membrane fluidity due to the increased levels of unsaturated fatty acids of both the n-3 and n-6 series in the membrane.

The effect of n-3 fatty acids on neutrophil chemiluminescence

The effect of dietary supplementation with n-3 polyunsaturated fatty acids (PUFAs) on the production of free oxygen radicals from activated neutrophils was investigated in healthy subjects, using chemiluminescence. In the first study 22 persons were give 4 g n-3 PUFAs daily for 6 weeks. There was a median reduction of chemiluminescence from neutrophils stimulated with opsonized zymosan of 37% (p < 0.001). The median content of eicosapentaenoic acid in platelets, used as an indicator for cellular fatty acid profile, increased from 0.70 to 2.80% (p < 0.001), and there was a significant negative correlation between the chemiluminescence signal and the content of eicosapentaenoic acid in platelets (p < 0.001). In a second, low-dose study 24 persons were allocated to daily supplementation with either 0.65 g n-3 PUFAs or with a control oil for 6 weeks. Compared to the control group there was a median reduction of 38 and 44% in chemiluminescence from neutrophils stimulated with opsonized zymosan and phorbol,12-myristate,13-acetate (PMA), respectively. Neither of these differences, however, was statistically significant. These findings lend support for a possible role of n-3 PUFAs in the management of inflammatory disorders.

Dietary fish-oil supplementation in humans reduces UVB-erythemal sensitivity but increases epidermal lipid peroxidation

Ultraviolet radiation (UVR)-induced erythema may be mediated in part by free radical-generated tissue damage, including lipid peroxidation. We have examined the effect of dietary fish oil rich in omega-3 fatty acids upon susceptibility to UVB-induced erythema and epidermal lipid peroxidation. Fifteen volunteers took 10 g fish oil, containing 18% eicosapentaenoic acid and 12% docosahexaenoic acid, daily for 3 or 6 months. Sensitivity to UVB was assessed at intervals on fish oil, and 2.5 months after stopping treatment. Paired skin shave biopsies were taken from six subjects, at baseline and 3 months, from both irradiated and control skin. Fatty acid composition was analyzed and thiobarbituric acid-reactive substances measured as an index of lipid peroxidation. With increasing time on fish oil the minimal erythema dose rose progressively, from 18.9 +/- 13.9 mJ/cm2 (mean +/- SD) at baseline to 41.1 +/- 16.6 mJ/cm2 at 6 months, p < 0.01. Ten weeks after stopping fish oil the minimal erythema dose fell to 23.1 +/- 4.9 mJ/cm2, p < 0.05. Epidermal total omega-3 fatty acids rose from 1.8 +/- 0.4% total fatty acids (mean +/- SEM) to 24.2 +/- 3.9% at 3 months, p < 0.01. This was accompanied by a rise in thiobarbituric acid-reactive substances in irradiated skin from 6 +/- 0.3 (mean +/- SEM) to 18.5 +/- 2.6 A532/g skin, p < 0.01. Hence dietary omega-3 fatty acids produce a pronounced reduction in UVB-erythemal sensitivity, although susceptibility of skin to lipid peroxidation is increased. Thus, omega-3 fatty acids may act as an oxidizable buffer, protecting more vital structures from free radical damage.

Effect of dietary omega-3 and omega-6 fatty acid sources on PUVA-induced cutaneous toxicity and tumorigenesis in the hairless mouse

Because of concern about psoralen-induced phototoxicity and photocarcinogenesis, we investigated the effects of dietary lipids in a mouse model in which 8-methoxypsoralen (8-MOP) and UVA (PUVA) therapy has been shown to be carcinogenic. SKH-Hr-1 hairless albino mice were fed diets containing either omega-3 or omega-6 fatty-acid sources (menhaden oil and corn oil, respectively). After 2 weeks on the diets, the mice were treated topically with 8-MOP and then exposed to UVA (5 J/cm2). Mice receiving the omega-3 fatty-acid source exhibited a marked decrease in inflammatory response and a more rapid repair, as expressed both grossly and microscopically. In support of the latter response, i.e. repair, ornithine decarboxylase activity was about 20% greater in animals receiving the omega-3 fatty-acid source. The effects of the dietary fatty acid sources on PUVA tumorigenesis were examined in long-term studies in which animals were treated topically with 0.01% 8-MOP thrice weekly after which they were exposed to UVA (1 J/cm2). These studies indicated that a dietary lipid rich in omega-3 fatty acid and known to exhibit anti-inflammatory properties can markedly ameliorate the course of PUVA toxicity but does not impede the course of PUVA tumorigenesis.

Evening primrose oil and marine oil in the treatment of psoriasis

The effect of dietary supplementation with a combination of n-3 (marine oil) and n-6 (evening primrose oil) essential fatty acids in the treatment of chronic stable plaque psoriasis was observed. Thirty-seven patients in a double-blind parallel trial were studied. There was no significant improvement in clinical severity of psoriasis or change in transepidermal water loss.

Highly purified omega-3-polyunsaturated fatty acids for topical treatment of psoriasis. Results of a double-blind, placebo-controlled multicentre study

We report the results of a multicentre, double-blind, placebo-controlled study of topical therapy with omega-3-polyunsaturated fatty acids (omega-3-PUFA) in 52 patients suffering from moderate plaque-type psoriasis. In each patient, two similar stable psoriatic plaques served as indicator lesions for the study. One indicator lesion was randomly assigned to treatment with topical preparations of highly purified omega-3-PUFA in one of two concentrations (1 or 10%), and the other was treated with placebo. Efficacy assessment was based on changes in local psoriasis severity index, area involved, erythema, desquamation, induration and pruritus. After 8 weeks of treatment, all indicator lesions had improved significantly, compared with baseline. However, no statistically or clinically relevant differences between the omega-3-PUFA-treated and the placebo-treated lesions were found. Therapy was well tolerated and, apart from one patient who developed perilesional eczema, no clinically relevant adverse events occurred. In conclusion, topical omega-3-PUFA were not effective in a randomized, placebo-controlled, double-blind setting. Results of non-blind trials should be (re-)considered with caution.

Influence of intravenous n-3 lipid supplementation on fatty acid profiles and lipid mediator generation in a patient with severe ulcerative colitis

N-3 fatty acids were supplied to a 36-year-old female patient suffering from ulcerative colitis and severe steroid side-effects, in a sequence of parenteral and enteral administration. During a moderately active period of disease, 200 ml d-1 fish oil-derived lipid emulsion (eicosapentaenoic acid [EPA], 4.2 g; docosahexaenoic acid [DHA], 4.2 g) was infused for 9 days, in parallel with rapid tapering of the steroid dose. Disease activity declined rapidly, and the patient was subsequently provided with 16 fish oil capsules per day (EPA, 2.9 g; DHA, 1.9 g) for 2 months. At the end of this period of therapy, severe colitis recurred with intestinal and extraintestinal manifestations. The n-3 lipid emulsion was then used for intravenous alimentation (29 days, maximum dose 300 ml per day); during this time, marked improvement of the inflammatory bowel disease was noted. During both periods of parenteral n-3 lipid administration, total plasma EPA and DHA contents increased several-fold, surpassing that of arachidonic acid; this plasma n-3 fatty acid enrichment was only maintained to a minor extent during the intermediate period of dietary fish oil supplementation. The intravenously administered EPA-containing triglycerides were rapidly hydrolyzed, as evidenced by the appearance of substantial quantities of EPA in the plasma free fatty acid fraction. Platelet and neutrophil total membrane content of EPA and DHA as well as n-3 fatty acid/AA membrane ratios similarly increased during the periods of intravenous n-3 lipid administration and declined during oral fish oil uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-inflammatory effects of eicosapentaenoic acid on experimental skin inflammation models

Anti-inflammatory effects of eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) were examined on three models of skin inflammation induced in mice by topical application of an arachidonic acid (AA) solution, ultraviolet-B (UVB) irradiation, and contact sensitization with dinitrofluorobenzene. Ear oedema reactions induced by AA and UVB irradiation were significantly suppressed in mice fed a daily dose of 300 mg/kg EPA for 2 weeks. The contact hypersensitivity reaction was not impaired by EPA. None of the skin reactions was significantly inhibited in mice fed DHA or safflower oil. The results suggest that EPA, but not DHA, has anti-inflammatory effects on AA- and UVB-induced acute inflammation reactions.

Diet and dermatology. The role of dietary manipulation in the prevention and treatment of cutaneous disorders

The role of dietary manipulation and vitamins in the prevention and treatment of certain skin diseases is reviewed. Manipulation of nutrition by either diet restriction or supplementation can effect cutaneous disorders such as skin cancer, wound healing, atopic dermatitis, psoriasis, and dermatitis herpetiformis.

Effect of dietary supplementation with very-long-chain n-3 fatty acids in patients with psoriasis

BACKGROUND

In several studies dietary fish oil has been found to have beneficial effect on psoriasis, but the results are contradictory and based mainly on open studies or studies of small numbers of patients.

METHODS

In a four-month double-blind, multicenter trial, we randomly assigned 145 patients with moderate-to-severe psoriasis to receive in their diet either highly purified ethyl esters of n-3 fatty acids ("fish oil"; 6 g of oil per day, containing 5 g of eicosapentaenoic and docosahexaenoic acid) or an isoenergetic amount of corn oil containing mainly n-6 fatty acids. All the patients were advised to reduce their intake of saturated fatty acids. A 48-hour dietary recall was performed, and the fatty-acid pattern in the serum phospholipids was monitored in a subgroup of patients.

RESULTS

In the fish-oil group, n-3 fatty acids were increased in serum phospholipids (P < 0.001), the ratio of arachidonic acid to eicosapentaenoic acid decreased (P < 0.001), and the level of n-6 fatty acids decreased (P < 0.001). In the corn-oil group, only docosahexaenoic acid increased significantly (P < 0.05). The ratio of polyunsaturated to saturated fatty acids increased in both groups. Plasma concentrations of triacylglycerol decreased from base line in the fish-oil group (P < 0.05). The score on the Psoriasis Area and Severity Index, as evaluated by the physicians, did not change significantly during the trial in either group. This was also true of a total subjective score reported by the patients, but a selected area of skin in the corn-oil group showed a significant reduction in the clinical signs (P < 0.05). Scaling was reduced from base line in both groups (P < 0.01). The fish-oil group had less cellular infiltration (P < 0.01), and the corn-oil group had improvement in desquamation and redness (P < 0.05). There was no significant difference in clinical manifestations between the groups. Among the patients in the fish-oil group, an increase in the concentration of n-3 fatty acids in serum phospholipids was not accompanied by clinical improvement, whereas in the corn-oil group there was a significant correlation between clinical improvement and an increase in eicosapentaenoic acid and total n-3 fatty acids.

CONCLUSIONS

Dietary supplementation with very-long-chain n-3 fatty acids was no better than corn-oil supplementation in treating psoriasis. Clinical improvement was not correlated with an increase in the concentration of n-3 fatty acids in serum phospholipids among the patients in the fish-oil group, whereas there was a significant correlation between clinical improvement and an increase in eicosapentaenoic acid and total n-3 fatty acids in the corn-oil group.

Growth inhibitory effect of eicosapentaenoic acid on cultured human epidermal keratinocytes

The effect of eicosapentaenoic acid (EPA, 20:5n-3) on the proliferation of cultured human epidermal keratinocytes was investigated. The keratinocytes were treated with 3 micrograms/ml of EPA for 48 h and then their fatty acid composition was analyzed by gas liquid chromatography. A significant amount of EPA was incorporated by the cells. The treatment with EPA at concentrations of 0.3-6.0 micrograms/ml resulted in a dose-dependent inhibition of the growth of the cells. These results indicate that EPA can be incorporated by cultured keratinocytes and change their fatty acid composition, which might endogenously affect their growth.

Long-term supplementation with n-3 fatty acids, II: Effect on neutrophil and monocyte chemotaxis

The effect of a daily supplement with 4 g of n-3 polyunsaturated fatty acids (PUFA) for 9 months to 24 healthy volunteers on neutrophil and monocyte chemotaxis was studied using the under-agarose technique. Autologous serum and n-formyl-methionyl-leucyl-phenylalanine were used as chemoattractants. The effect after 9 months of supplementation with n-3 PUFA was also compared to results after short-term supplementation with n-3 PUFA for 6 weeks. Monocyte chemotaxis was reduced after 9 months of supplementation with n-3 PUFA to the same extent as after 6 weeks supplement. Neutrophil-directed migration towards chemoattractants was reduced after 9 months on fish oil, and this decrease was significantly greater than the decrease obtained after 6 weeks of supplementation. The spontaneous migration of neutrophils was significantly attenuated after 9 months compared to baseline and to 6 weeks. These findings lend support to a role for n-3 PUFA in the management of chronic inflammatory and atherosclerotic vascular diseases.

Topical fish oil in psoriasis--a controlled and blind study

Omega-3 polyunsaturated fatty acids compete with arachidonic acid as substrates for lipoperoxidases, which transform them into leukotrienes with low biological activity. As this process, in skin, may benefit psoriatic patients, a randomized controlled single blind-study was carried out on a sample of 25 patients. In the study fish oil (FO) was compared with liquid paraffin (LP); both were topically applied and administered daily for 6 h under an occlusive dressing over a 4-week period. Evaluations were performed weekly assessing erythema, scaling, plaque thickness (induration) and itching. The results showed statistically significant improvement in erythema and scaling for both treatments compared to basal values; significant differences between treatments were achieved in scaling but not in erythema. Compared to baseline, FO significantly improved plaque thickness while LP did not. After 4 weeks, FO proved to be significantly better than LP. All patients accepted the treatment despite its unpleasant smell. Irritation and a burning sensation were reported in the FO treated plaque of one patient. This adverse effect reverted after completing the treatment. These findings demonstrate that topical FO shows a better performance than LP under an occlusive dressing.