Bharti Jayshankar
December 4, 2024: The link between highly ultra-processed food (UPF) and various health issues such as obesity, diabetes, cardiovascular risks and depression is well established. Now a research letter published in JAMA Dermatology says that UPF intake can activate psoriasis.
Laetitia Penso, Ph.D., from Paris-Est University, and colleagues did a cross-sectional study from the Nutri-Net-Santé cohort study conducted between 2021 and 2022 in France, to examine the association between UPF intake and active psoriasis. There were 18,528 participants in the study, ages 62–70. Of these, 74% were women and 26% were men.
Psoriasis and food intake
The participants were classified by their psoriasis status based on self-reported diet. Participants who never had psoriasis were compared with those who had active psoriasis and those who had had psoriasis but were not currently active in terms of their dietary intakes of ultra-processed foods (UPF)
UPF intake in grams/day was extracted and divided into tertiles, from minimum to maximum intake (tertiles 1 and 3, respectively).
Of the 18,528 participants, 1,825 (10 percent) had psoriasis, with 803 active cases (4 percent). Compared with the never-had and nonactive groups, the active-psoriasis group had a lower proportion of females and a higher proportion of individuals with a body mass index (BMI) greater than 30 kg/m2.
High-intensity physical activity occurred less often in the active and nonactive groups than in the never-had group. The researchers found that UPF intake differed between the active and never-had groups in an unadjusted analysis (tertile 3 odds ratio, 1.52). High UPF intake was more likely than lower UPF intake in the active group after adjustments (tertile 3 adjusted odds ratio, 1.36).
“After adjustments for age, BMI, alcohol intake, and comorbidities, the results remained significant, suggesting that UPF intake has a proinflammatory action separate from high BMI,” the authors write.
Study limitations
Prof Wendy Hall, Department of Nutritional Sciences, King’s College London, in her comment on the research, said: “The article is a brief research letter rather than a full article, and therefore limited information is provided on the methodology used to assess UPF intake. A strength of the analysis is that the analysis was adjusted for confounding factors including body mass index (BMI), which is important as a high BMI is a result of high intake of energy-dense foods and is also a risk factor for psoriasis. The topic of diet and psoriasis has been relatively understudied so it is important that associations are explored in large cohorts such as this one in order to generate hypotheses that can be tested in randomised controlled trials, and then eventually support the development of clinical dietary guidelines.”
UPF and risk to health
Ultra-processed foods are often designed to be convenient and have a long shelf life, which involves use of chemicals, rather than be nutritious. They often contain artificial colors, flavors, and preservatives, all of which are harmful to health. Previous studies have proved the link between ultra-processed food and the risk of serious health issues.
A 30-year US study found that participants who consumed the most ultra-processed foods had a 4% higher risk of all-cause mortality. A study in the British Medical Journal found that diets high in ultra-processed foods are linked to an increased risk of cardiovascular disease. Some research has linked mental disorders and depression to excessive intake of UPF.
The abstract can be accessed here.
