Ultra-Processed Foods Linked to Psoriasis Flare-Ups

A new study of more than 18,000 participants highlights the potential influence of diet on inflammatory diseases.

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Researchers have found a potential dietary connection to psoriasis, a chronic disease that leads to the buildup of thick, scaly patches of skin and affects an estimated 7.5 million Americans.

They suggest that this discovery may shed light on the potential influences diet could have on inflammatory diseases.

More Than 1.5 Times Increased Risk of Flare-Ups

The study, published on Nov. 27 in JAMA Dermatology, involved 18,528 participants, among whom 10 percent reported to have psoriasis. Researchers assessed participants’ intake of ultra-processed foods (UPFs) using a validated self-diagnosis questionnaire. Psoriasis status was categorized into three groups: never had psoriasis, nonactive psoriasis, or active psoriasis. Among the psoriasis cases, 803 were classified as active.

The researchers used data from the NutriNet-Santé cohort study, a major French nutrition study tracking more than 500,000 participants, to explore links between diet and health outcomes.

The results showed demographic differences among those with active psoriasis. The active psoriasis group consisted of a smaller proportion of females (68 percent versus 74 percent) and a higher rate of individuals with a body mass index (BMI) greater than 30 (16 percent versus 9 percent) compared with those who had never experienced psoriasis. Additionally, the study highlighted that high-intensity physical activity was less common among individuals with active psoriasis.

Initial analyses indicated a significant difference in UPF consumption between people with active psoriasis and those without the condition. Specifically, participants with the highest intake of UPF were 1.52 times more likely to have active psoriasis than those who never had the condition.

Even when controlling for factors such as age, body weight, alcohol consumption, and other health issues, the association remained significant. In the adjusted analysis, the likelihood of having active psoriasis was still 1.36 times greater among individuals with high UPF intake.

UPFs can cause inflammation for several reasons, including the following: 

• Food Additive Content: Additives such as emulsifiers, sweeteners, colors, and nanoparticles can alter the gut’s microbiota and permeability, which can lead to inflammation.
• High Salt Content: The salt in UPFs can increase the number of pro-inflammatory T-cells the body produces.
• High Sugar Content: Consuming too much sugar can lead to low-grade chronic inflammation.

UPFs are foods that have been significantly changed from their original state through industrial processes. Examples include soft drinks, chips, chocolate, candy, ice cream, and sweetened breakfast cereals.

More Research Needed to Confirm Findings

“High UPF intake was associated with active psoriasis status,” the study authors wrote, noting that UPF intake appears to exert a pro-inflammatory effect independent of high BMI.

They acknowledged several study limitations, including the potential for misclassification of psoriasis cases due to the self-reported nature of the data. However, they pointed out that the sensitivity and specificity of this self-diagnosis method had been validated in previous research.

Further research is critical for understanding the potential impacts diet could have on inflammatory diseases.