Risk Factors for Inflammatory Bowel Disease: Ultra-Processed Food (Part 1)

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N Narula et al. Clin Gastroenterol Hepatol 2023; 21: 2483-2495. Open Access! Food Processing and Risk of Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

JA Fitzpatrick et al. Clin Gastroenterol Hepatol 2023; 21: 2478-2480 (editorial). Open Access! Ultra-processed Foods and Risk of Crohn’s Disease: How Much is Too Much?

Figure 1 from editorial: The NOVA classification of food

A total of 1,068,425 participants were included (13,594,422 person-years) among 5 cohort studies published between 2020 and 2022. The average age of participants ranged from 43 to 56 years. Key findings:

  • Crohn’s disease:  During follow-up, 916 participants developed CD, and 1934 developed UC. There was an increased risk for development of CD for participants with higher consumption of ultra-processed foods compared with those with lower consumption (HR, 1.71; 95% CI, 1.37–2.14; I2 = 0%) and a lower risk of CD for participants with higher consumption of unprocessed/minimally processed foods compared with those with lower consumption (HR, 0.71; 95% CI, 0.53–0.94; I2 = 11%). 
  • Ulcerative colitis: There was no significant association between risk of UC and ultra-processed foods (HR, 1.17; 95% CI, 0.86–1.61; I2 = 74%) or unprocessed/minimally processed foods (HR, 0.84; 95% CI, 0.68–1.02; I2 = 0%).

The associated editorial by Fitzpatrick et al, notes that “there are plausible mechanisms that explain the associations of higher UPFs and development of CD, such as: (1) displacing the intake of minimally processed foods and subsequently reducing exposure to beneficial micronutrients, antioxidants, and phytochemicals; (2) driving overconsumption of total calories7; and (3) increasing exposure to non-nutritive food substances that have been implicated in the development of CD in pre-clinical studies…The notion is that a lower UPF intake is better, but a cutoff value remains elusive.”8

My take (borrowed from editorial): “the population studies have indicated that the extremes of UPF intake are related to risk of CD and that such associations are underpinned by plausible biological mechanisms, suggesting causality.”

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