Growing evidence suggests that nutrition plays a major role in the development of psoriasis, with the likelihood that body weight and diet will exacerbate or trigger the disease. In a recent review, Italian researchers describe environmental risk factors for psoriasis, with a particular focus on obesity and nutrition in the management of the condition.
The review paper, “Environmental Risk Factors in Psoriasis: The Point of View of the Nutritionist,” was published in the International Journal of Environmental Research and Public Health.
Psoriasis is a chronic autoimmune disease with systemic pro-inflammatory activation. Both environmental and genetic factors have been associated with the development of this skin disorder.
According to recent data, patients with psoriasis have a higher prevalence of obesity and metabolic syndrome, which translates to a higher cardiovascular risk.
The evidence of the impact psoriasis has on patients’ quality of life, productivity, and physical, social, and emotional well-being demonstrates that “the treatment of environmental modifiable risk factors (diet, nutrition, or physical activity) and modulation of the systemic inflammatory response are important therapeutic goals in the integrated management of psoriatic patients,” according to the review in the International Journal of Environmental Research and Public Health.
Researchers focused on the possible relationship between psoriasis and body weight beyond the sole measure of BMI, and on the roles of obesity, diet, and nutrition on psoriasis and its medical treatment.
The relationship between obesity and psoriasis is probably bidirectional, with obesity being a risk factor for psoriasis and psoriasis favoring obesity. Research suggests that adipocytes (fat cells), cells with inflammatory roles, and inflammatory-type macrophages are involved in the link between psoriasis and obesity. Other studies have also reported an association between psoriasis and a sedentary lifestyle.
Importantly, the authors emphasize that patients with a BMI greater than 30 kg/m2, which, according to current World Health Organization guidelines, is a sign of obesity, may potentially interfere with patients’ ability to experience the full therapeutic effect of psoriasis therapy.
“This could be for two possible reasons,” the authors wrote. “It may be a consequence of decreased drug distribution into the body as a result of increased body mass, or it may be a consequence of increased pro-inflammatory cytokine release as a result of the adipocyte dysfunction.”
The authors caution that BMI is a limited tool because it’s a measure of excess weight rather than excess fat, poorly distinguishing between fat mass and lean or bone mass.
The National Heart, Lung and Blood Institute Clinical Guidelines recognizes this limitation and recommends waist circumference (WC) measurement as an additional assessment for fat distribution, particularly the dangerous visceral fat, the main source of inflammatory cytokines in obesity.
The few studies assessing this connection have suggested a strict association between WC and psoriasis, probably resulting from the exacerbation of psoriasis due to inflammatory molecules produced in visceral fat.
Researchers also focused on the impact of obesity in the treatment of psoriasis. Obese patients have been associated with a decreased response to systemic and biologic therapies, especially regarding drugs administered in fixed doses than those in which the dose is adjusted to the patient’s weight.
“In addition to the potential decrease in the effectiveness of treatment and the greater risk of adverse effects, obesity also substantially increases the cost of treatment with drugs prescribed in weight-adjusted doses,” the authors wrote.
Regarding dietary choices, the authors report that the rich and diverse Mediterranean diet may have protective effects against psoriasis and other chronic inflammatory diseases. The nutritional assessment should be an integral component of managing psoriatic patients, they said.
Also important for psoriasis patients is education about modifying environmental factors such as diet, nutrition, weight, and physical activity, the authors said.