Ultra-processed foods linked to higher psoriasis risk

New research links ultra-processed food intake to higher psoriasis risk, even after accounting for genetics, BMI, and lifestyle, highlighting the potential of dietary changes in preventing chronic skin conditions.

Study: Ultra-Processed Food Consumption and the Risk of Psoriasis: A Large Prospective Cohort Study. Image Credit: Ekaterina Markelova / Shutterstock.com

A recent study published in the journal Nutrients explores the role of ultra-processed food (UPF) consumption on the risk of psoriasis.

What causes psoriasis?

Psoriasis is a chronic skin condition characterized by inflamed, scaly, and itchy patches. Psoriasis lesions are not site-specific; however, this skin condition often affects the palms, soles, and nails. Psoriasis may also increase the risk of mental health issues like depression and anxiety, as well as cardiovascular disease (CVD) and Crohn’s disease.  

Psoriasis affects 2-3% of people worldwide, with the incidence of this condition differing based on geographic regions, ranging between 30 and 321 cases for every 100,000 people. Although there is no cure, several therapeutic approaches, including phototherapy, prescription drugs, and biologic agents, are currently used to manage psoriasis symptoms.

Certain dietary components may induce systemic inflammation, thereby increasing the risk of psoriasis. The consumption of UPFs, for example, is associated with inflammatory allergic conditions, as demonstrated by higher levels of the allergy-associated immunoglobulin E (IgE), childhood asthma, and allergic symptoms in eczema.

What are UPFs?

UPFs are created through various industrial processes to increase the palatability of food products while extending their shelf life. However, the processes and ingredients used to produce UPFs significantly reduce their nutritional profile, as they are often high in sugar, oil, and other additives like emulsifiers and artificial flavors.

The NOVA system classifies all foods and food products into four groups based on the extent of industrial processing used during their production. Foods in the NOVA group 1 are unprocessed or minimally processed, whereas group 2 includes any ingredients that have undergone industrial processing, such as oils, fats, sugar, and salt, which may be used to prepare, season, and/or cook group 1 foods.

NOVA group 3 includes food products from groups 1 and 2 that have subsequently undergone preservation methods like canning, bottling, or non-alcoholic fermentation. UPFs are classified as NOVA group 4 foods.

UPFs currently contribute to over 50% of the total energy intake in the United States, Canada, and the United Kingdom. This global upward trend continues to rise, as UPF sales in other nations like Australia and Western European countries have also accelerated.  

UPF consumption has been widely studied for its role in increasing the risk of noncommunicable diseases like CVD, type 2 diabetes, and Crohn’s disease. However, it remains unclear how UPF consumption may impact psoriasis development.

About the study

The current study explores differences in the incidence of psoriasis by UPF consumption based on the NOVA classification system. A total of 121,019 study participants between 40 and 69 years of age were included in the analysis.

The researchers determined the association between the risk of new-onset psoriasis and UPF intake and investigated the role of inflammation and body mass index (BMI) in this association.

Study findings

Individuals who consumed more UPFs were more likely to be younger White males with a higher BMI, less habitual physical activity, and a history of current or previous cigarette smoking. The energy intake among these study participants was also higher.

UPF consumption was categorized into four different quartiles, with the first quartile representing the reference or lowest group. After a median follow-up period of 12 years, the risk of psoriasis was 7% higher in the second quartile of UPF intake as compared to the reference group.

The risk of psoriasis continued to rise as UPF consumption rates increased, with a 19% and 23% higher risk reported among individuals in the third and fourth quartiles, respectively. For every 10% increase in UPF consumption, the risk of psoriasis rose by 6%.

Among those with an increased genetic risk of psoriasis, higher UPF intake led to a nearly threefold increased risk of developing psoriasis as compared to those with a low genetic risk and low UPF consumption. After adjusting for age, sex, BMI, smoking and drinking, physical activity, and socioeconomic deprivation, no significant change in these associations was observed.

The Inflammation (INFLA) score contributed to 6.5% of the association between psoriasis risk and UPF intake, whereas BMI mediated 30.5% of this risk.

These observations agree with previous studies reporting increased rates of obesity, which independently increases the risk of psoriasis incidence and severity, associated with UPF consumption. UPF consumption also leads to low-grade dietary and gut inflammation, which is worsened by the concomitant reduction in the consumption of fresh and/or unprocessed foods with anti-inflammatory benefits.

This underscores the crucial role of controlling UPF intake in the primary prevention of psoriasis.”

When UPFs were replaced with category 1 food, the estimated risk of psoriasis was reduced by 18%.

Conclusions

The current prospective study is the first to estimate the incidence of psoriasis in relation to UPF consumption in United Kingdom Biobank participants. Together, these findings indicate a 6% increased risk of psoriasis with each 10% increase in UPF consumption, with this risk reduced by 18% if 20% of UPFs were replaced with category 1 foods.

Increased UPF consumption is associated with a higher risk of psoriasis.”