Because white meat, unprocessed red meat, dairy, starch, fruit, vegetables, and legumes were not associated with the development of IBD, the way that the food is processed may confer this risk of IBD, rather than the food itself.
Individuals with a higher intake of ultra-processed foods may have a higher risk of inflammatory bowel disease (IBD), according to new research published in The BMJ.
IBD is most common in industrialized countries and researchers believe that dietary factors may play a role, according to the study. Ultra-processed foods include packaged baked goods and snacks, carbonated drinks, sugary cereals, ready-to-eat meals containing additives, and reconstituted meat and fish products. All of these products often contain high levels of added sugar, fat, and salt, but lack vitamins and fiber.
To investigate the link between ultra-processed foods and IBD, investigators analyzed detailed dietary information from 116,087 adults between 35 and 70 years of age and living in 21 low-, middle-, and high-income countries. These adults were taking part in the Prospective Urban Rural Epidemiology (PURE) study, which is examining the impact of societal influences on chronic diseases.
These participants were enrolled in the study between 2003 and 2016 and were assessed at least every 3 years. Investigators recorded new diagnoses of IBD, including Crohn disease or ulcerative colitis, over an average follow-up of 9.7 years. During this period, 467 participants developed IBD, 90 of whom were diagnosed with Crohn disease and 377 with ulcerative colitis.
After accounting for other potentially influential factors, the research team found that a higher intake of ultra-processed foods was linked to a greater risk of IBD. For example, they found an 82% increased risk of IBD among individuals who consumed 5 or more servings of ultra-processed foods per day compared to those who consumed less than 1 serving. They found a 67% higher risk of IBD among those who consumed between 1 and 4 servings per day.
Different subgroups of ultra-processed foods, such as soft drinks, refined sweetened foods, salty snacks, and processed meat, were associated with higher risks of IBD. In contrast, white meat, red meat, dairy, starch, fruit, vegetable, and legume intake were not associated with IBD, according to the study.
These results were consistent for both Crohn disease and ulcerative colitis and were similar after researchers conducted further analysis to test the risk of developing IBD based on age and region. According to the study authors, this suggests that the findings are robust.
Notably, however, the study cannot establish causality because it was an observational study. The researchers also noted that their results relied on self-reported diagnoses and did not account for dietary changes over time. They also said they cannot rule out the possibility that other unmeasured factors could have affected the results.
Still, the authors said their findings suggest that intake of ultra-processed foods could increase the risk of IBD. They hypothesized that because white meat, unprocessed red meat, dairy, starch, fruit, vegetables, and legumes were not associated with the development of IBD, the way that the food is processed may confer this risk of IBD, rather than the food itself.
“Further studies are needed to identify specific potential contributory factors among processed foods that might be responsible for the observed associations in our study,” the authors concluded in the press release.
Ultra-processed food linked to higher risk of IBD. News release. EurekAlert. July 14, 2021. Accessed July 21, 2021. https://www.eurekalert.org/pub_releases/2021-07/b-ufl071221.php