N Narula at al. BMJ 2021; 374: n1554. Open Access: Association of ultra-processed food intake with risk of inflammatory bowel disease: prospective cohort study
Background: “Processed foods often include many non-natural ingredients and additives such as artificial flavours, sugars, stabilisers, emulsifiers, and preservatives. Detergents and emulsifiers that are added to foods might have a detrimental effect on the gut barrier. Carboxymethylcellulose has been shown to increase bacterial adherence to intestinal epithelium and might lead to bacterial overgrowth and infiltration of bacteria into the spaces between intestinal villi. Polysorbate 80, an emulsifier commonly used in processed foods, increases translocation of bacteria such as Escherichia coli across M cells and Peyer’s patches in people with Crohn’s disease.”
Methods: Using food questionnaires, the authors prospectively followed 116 087 adults aged 35-70 years from 21 low, middle, and high income countries from 2003 to 2016 (median follow-up of 9.7 years).
- After adjustment for potential confounding factors, higher intake of ultra-processed food was associated with a higher risk of incident IBD with a hazard ratio of 1.82 for ≥5 servings/day and 1.67 for 1-4 servings/day (compared to <1 serving/day)
Since this is an observational study, this does not prove a causal association between these foods and inflammatory bowel disease. Nevertheless, limiting the consumption of ultraprocessed foods is a good idea as these foods may increase the risk of other health problems as well, including cardiometabolic disease and cancer (Gastroenterol 2022; 162: 652-54). This will be difficult, though, as in the U.S. more than half of calories consumed are from ultraprocessed foods.
My take: This study supports the notion that more fresh foods in our diets is beneficial.
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