**4. Gluten**

Celiac disease is an enteropathy associated with different extra-intestinal manifestations, such as anemia, transaminase elevation, osteopenia, neurological conditions, emotional and psychiatric disorders, auto-immune disease and dermatological problems. This disease is characterized by an allergy to gluten (a protein found in wheat, oats, rye and barley), leading to malabsorption and atrophy of the intestinal villi, which improves with a glutenfree diet (Abenavoli et al., 2006).

This gluten-sensitive enteropathy tends to bemildly symptomatic and even asymptomatic, which may explain the association between latent gluten sensitivity and psoriasis (Wolters, 2005). A number of studies report an association between celiac disease and psoriasis (Michaelsson et al., 2000; Woo et al., 2004). According to some authors, however, this association is controversial due to currently limited data (Addolorato et al., 2003; Collin & Reunal, 2003). Since both celiac disease and psoriasis are related to T helper 1 (Th1) cytokines, this association could be caused by the activation of Th1 by the interleukins IL1 and IL8, stemming from the rapid division of keratinocytes (Ojetti et al., 2003).

There is no consensus among current literature regarding the high prevalence of patients with psoriasis and antibodies associated to celiac disease (Ricketts et al., 2010). Thus, there

Food, Nutrition and Diet Therapy in Psoriasis 361

al., 1993; Pinton et al., 1995; Azzini et al., 1995). Low levels of selenium are related to the severity of psoriasis and may occur due to low food intake or excessive flaking of the skin (Serwin et al., 2003). Serwin et al. (2003) found that selenium levels were significantly lower in patients with a diagnosis of psoriasis for more than three years in comparison to healthy

Kharaeva et al. (2009) demonstrated for the first time that the combination of conventional therapy and supplementation with vitamin E, co-enzyme Q10 and selenium resulted in an improvement in the clinical condition of patients with severe psoriasis as well as a reduction in oxidative stress. Supplementation using inorganic forms of selenium (sodium selenite and selenate) is also reported to lead to clinical improvement in patients with psoriasis

Vitamin D is a pro-hormone that can be produced from 7-dehydrocholesterol through the exposure of skin to ultraviolet B rays of the sun. Besides its importance in the homeostasis of calcium and bone metabolism, calcitriol (the active form of vitamin D) has effects on more than 30 types of tissue, including skin (Wolters, 2005). Vitamin D plays an important role in reducing the risk of a number of chronic diseases, such as auto-immune diseases, infectious diseases, cardiovascular diseases and some forms of cancer (breast, colon-rectal and prostate

Vitamin D plays an essential role in cell proliferation, differentiation, apoptosis and angiogenesis.Vitamin D also has beneficial effects on inflammatory diseases medicated by Th1 lymphocytes, such as diabetes, psoriasis, Crohn's disease and multiple sclerosis (Cantorna et al., 2004; Holick, 2007; Ikeda et al., 2010). Vitamin D has proven to be highly effective in the treatment of psoriasis, as patients having received vitamin D for the treatment of osteoporosis exhibited an improvement in psoriasis (Abramovits, 2009; Smith et al., 2009; Van De Kerkhof, 2005). Due to the function of calcitriol and its analogs in psoriasis, oral supplementation with vitamin D should be considered in patients who do not make use of topical treatment with this vitamin, as vitamin D deficiency is frequent in these

Data from the literature demonstrates the efficacy of using intramuscular and systemic vitamin B12 in patients with psoriasis in addition to the positive effects of topical vitamin

Zinc deficiency has been associated with the presence of psoriatic plaque (Smith et al., 2009). However, there is little evidence on the benefits of oral supplementation as of yet (Burrows et al., 1994). Moreover, there are no recommendations regarding the amount or chemical

volunteers (38.69 vs 48.41; p < 0.05).

(Fairris et al., 1989; Pinton et al., 1995).

cancer) (Fu &Vender, 2011).

**8. Vitamin B12** 

**9. Zinc** 

B12 (Ricketts et al., 2010).

individuals (Holick, 2003; Wolters, 2005).

form that offers the best beneficial effects.

**7. Vitamin D** 

is a need for prospective studies in order to determine the incidence of celiac disease and the real percentage of increased levels of antigliadin, antiendomysial and anti-tissue transglutaminase antibodies in patients with psoriasis (Ricketts et al., 2010).

A gluten-free diet can improve skin lesions even in patients without celiac disease but with the antigliadin antibodies IgA and IgG, which are important to the diagnosis of celiac disease (Michaelsson et al., 2003). Likewise, studies indicate that a gluten-free diet leads to an improvement in rheumatoid arthritis, which is another chronic inflammatory disease (Hafstrom et al., 2001). Data remains scarce in regards to the mechanisms involved in the association between celiac disease, psoriasis and a gluten-free diet in skin lesions. A number of hypotheses have been raised, such as an alteration in intestinal permeability, immune mechanisms and vitamin D deficiency (Abenavoli et al., 2006).
