Nutritional influences in psoriasis

Abstracts

A psoríase é uma doença inflamatória de pele, mediada por células T, hereditária, que sofre influência ambiental. Ingestão elevada de ômega-3, jejum, dietas hipocalóricas e vegetarianas mostram efeitos benéficos. Alguns pacientes que apresentam anticorpos antigliadina IgA/IgG, com sensibilidade ao glúten, melhoram após a retirada deste. O calcitriol é usado no tratamento tópico. Ingestão de álcool pode exacerbar a doença. Neste trabalho, analisam-se fatores dietéticos e descrevem-se seus benefícios na psoríase.

Ácidos graxos ômega-3; Antioxidantes; Bebidas alcoólicas; Dieta; Glúten; Psoríase

COMMUNICATION

Nutritional influences in psoriasis

Maria Lúcia Diniz Araujo^I; Maria Goretti P. de A. Burgos^II; Isis Suruagy Correia Moura^III

^I

^IIPh.D. in Nutrition. Specialist in Enteral and Parenteral Nutrition Therapy, Sociedade Brasileira de Nutrição Parenteral e Enteral (SBNPE). Specialist in Clinical Nutrition, Associação Brasileira de Nutrição (Asbran). Dietitian of the Dermatology Clinic, Hospital das Clínicas da Universidade Federal de Pernambuco (HCUFPE). Researcher dietitian at the Universidade Federal de Pernambuco (UFPE) - Recife (PE), Brazil.

^IIIResident dietitian at the Dermatology Clinic, Hospital das Clínicas da Universidade Federal de Pernambuco (HCUFPE) - Recife (PE), Brazil.

^{Mailing Address}

ABSTRACT

Psoriasis is an inherited inflammatory skin disease mediated by T-cells and influenced by environmental factors. High intake of omega-3, fasting, low-calorie and vegetarian diets show beneficial effects. Some patients presenting IgA/IgG antigliadin antibodies and who are gluten-sensitive improve after a gluten-free diet. Calcitriol is used in topical treatment. The use of alcohol may exacerbate the disease. In this report, diet factorsare analyzed and their benefits in psoriasis are described.

Keywords: Antioxidants; Alcoholic beverages; Diet; Gluten; Psoriasis

INTRODUÇÃO

Psoriasis is a chronic inflammatory skin disease mediated by T-cells and characterized by erythematous scaling lesions, increased cell proliferation and abnormal patterns of keratinocyte differentiation^1,2. The estimated worldwide prevalence is 2%^1,3, ranging from 0.6% and 4.8%, with no predilection for sex or age, and it is more frequent between the third and fourth decades of life, in females and individuals with a positive family history^4,5.

The causes are unknown, but genetic predisposition³, associated to environmental factors, such as smoking, alcohol, foods, infection, drugs and stressful events, could be a reasonable etiologic explanation³.

The prevalence and severity of psoriasis decrease during fasting. Low-calorie diets lead to relief of symptoms² and might be important adjuvant factors in prevention and treatment of moderate non-pustular psoriasis⁴.

Although many mechanisms have been discussed, the direct cause of these positive effects in symptoms are still not clear2. The most important explanation is probably reduced intake of arachidonic acid (AA), resulting in lower production of inflammatory eicosanoids. During fasting, there is less activation of the TCD4 cells and increased number and/or function of interleukin ⁴ (anti-inflammatory cytokine)¹, and calorie restriction leads to reduced oxidative stress¹.

Vegetarian diets may be beneficial to all patients with psoriasis, since there is decreased intake of AA and consequent reduction in inflammatory eicosanoid formation. High concentrations of AA and its pro-inflammatory metabolites were observed in psoriatic lesions, as well as in other autoimmune and inflammatory disorders. A therapeutic option in psoriasis is to replace AA by an alternative fatty acid (FA), especially eicosapentaenoic acid (EPA), which may be metabolized by the same enzyme pathways of AA^2,5.

As to effects of oral supplementation with omega-3 in this disease, the results are contradictory and not clear concerning the dose to be used5. Most studies present positive effects; however, the outcomes of randomized controlled trials are less effective². Despite inconsistent results, intake of fish rich in omega-3 is recommended. In patients with acute psoriasis, parenteral infusions of omega-3 might be beneficial².

Recent studies showed an association between celiac disease (CD) and psoriasis6; nevertheless, such relation is still very controversial, since there are scarce data6. Regarding gluten-free diet, it is known that it may improve the skin lesions, even in CD patients, but with IgA and IgG antigliadin antibodies⁷. There is scarce information in the literature to explain the mechanisms involved in the association between CD, psoriasis and gluten-free diet in skin lesions. Several hypotheses have been put forward, such as changes in intestinal permeability, immune mechanisms and deficiency of vitamin D6.

Oxidative stress and increased production of free radicals have been related to skin inflammation in psoriasis². Some studies showed that individuals with this disease have high concentrations of malonaldehyde, a lipid peroxidation marker, and an impaired antioxidant status, with reduced levels of -carotene, -tocopherol and selenium⁷.

Selenium has immunomodulating and antiproliferative properties. The literature reports that patients with inflammatory skin conditions, malignant melanoma and cutaneous T-cell lymphoma present low concentrations of this element⁸. Selenium low levels may be a risk factor for developing psoriasis, but there are few articles published about it⁷. Decreased levels of selenium are related to severity of the disease and may be due to low food intake or excessive skin scaling⁸.

Among other factors that may increase oxidative stress and reduce natural antioxidant levels, high alcohol consumption and active and/or passive smoking have been reported in individuals with history of the disease for over three years⁸. Young and middle-aged men present risks with alcohol ingestion, whereas in females this is not a risk factor but it aggravates the clinical picture⁹. Psoriatic patients should avoid drinking alcoholic beverages, primarily during the exacerbation periods, when there is a high risk of hepatic cirrhosis associated with methotrexate or other hepatotoxic treatments².

Calcitriol and its analogues have antiproliferative and prodifferentiative effects, which justify their importance in psoriasis. Oral supplementation of vitamin D should be considered in patients with psoriasis who are not on topical treatment with this vitamin^2,10.

Finally, it could be stated that diet is an important factor in the pathogenesis of the psoriasis. Although the results described in the literature about oral supplementation with fish oil are not consistent, patients can be oriented to eat fish rich in omega-3 due to its benefits to the disease. For inpatients with acute disease, parenteral infusions of polyunsaturated fatty acid are recommended. Further studies should be carried out to understand the role of gluten-free diet, which might reduce severity of the disease in patients with antibodies. Vitamin D is a therapeutic choice due to its immunoregulating and antiproliferative activities.

REFERENCES

How to cite this article: Araujo MLD, Burgos MGPA, Moura ISC. Influências nutricionais na psoríase. An Bras Dermatol. 2009;84(1):90-2.

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Publication Dates

• Publication in this collection
  23 June 2009
• Date of issue
  Feb 2009

History

• Received
  22 Dec 2008
• Accepted
  22 Dec 2008