A dietary clue to explain the high global incidence of inflammatory bowel disease

Why is this important?

CD has been associated with non-Mediterranean and pro-inflammatory dietary habits, as well as low fiber, zinc and potassium intakes, whereas UC has been associated with high linoleic acid, low docosahexaenoic acid and high consumption of red meat. These findings highlight the different impact of diet on the development of these two diseases. Recently, studies have focused on the association of the food manufacturing method and in particular their ultra-transformation and the occurrence of these chronic inflammatory diseases. Ultra-processed foods contain in particular non-natural ingredients such as artificial flavourings, stabilizers, sweeteners, stabilizers, emulsifiers, etc. and compounds transformed by industrial processes which increase intestinal permeability and promote dysbiosis. This systematic review of the literature and meta-analysis provides insight into the data that currently exist on the risk associated with the development of IBD depending on the consumption of more or less processed products.

Methodology

A literature review was conducted to identify studies published up to October 2022 regarding the association between the consumption of processed foods and the risk of CD or UC.

Principle results

Overall, five cohort studies were identified. Data from 1,068,425 people were therefore included in the analyses. These were all released between 2020 and 2022.

Four of them were qualified as high quality (score≥7 on the Newcastle-Ottawa scale).

The average age of the participants was between 43 and 56 years old (55% to 83% female).

During follow-up, 916 subjects developed CD and 1,934 UC. The proportion of consumption of ultra-processed products varied from 13% to 21% in the lowest quintiles and between 45% and 51% in the highest.

In the general population, the highest consumers of ultra-processed foods had a 71% increased risk of developing CD compared to those who consumed the least (hazard ratio (HR) 1.71 [1,37-2,14]the heterogeneity of the studies was very low I²=0%).

The highest consumers of minimally or unprocessed foods had a 29% lower risk of developing CD compared to those who consumed the least (HR 0.71 [0,53-0,94]I²=11%).

No association might be demonstrated between the consumption of ultra-processed foods or minimally or unprocessed foods and the risk of UC.