Psoriasis is a chronic inflammatory
skin disease, which does not have effective treatment options. However,
olive oil has been suggested as an alternative to treat
psoriasis, but no study has evaluated the mechanisms involved in the effects of
olive oil on
psoriasis. Thus, the current study investigated whether
olive oil could ameliorate psoriasiform skin
inflammation. To test this, mice received topical application of
imiquimod to induce
inflammation and were treated orally with
olive oil. Human immortalized keratinocytes were also treated with
imiquimod and
olive oil. Epidermal thickness and keratinocyte proliferation were increased in
imiquimod-induced lesions of
olive-oil-treated animals. In both in vitro and in vivo studies,
protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) were elevated following
imiquimod and
olive oil administration. Inhibition of Nrf2 abolished the increased proliferation of keratinocytes treated with
imiquimod and
olive oil, demonstrating the role of Nrf2 in
olive oil-mediated exacerbation of psoriasiform skin
inflammation. In addition, lower levels of
linoleic acid and higher levels of
oleic acid were observed in
imiquimod- and
olive-oil-treated animals, which may also contribute to the adverse effects of
olive oil on
psoriasis. In conclusion, dietary intake of
olive oil aggravates the symptoms of psoriatic skin lesions through the overexpression of Nrf2 and an imbalance in oleic and
linoleic acids levels, suggesting that a diet rich in
olive oil may have significant negative effects on
psoriasis.