The potential hazards of ultra-processed foods on gastrointestinal health

• Reframes UPFs identification though specific criteria for industrial processing processes and nutritional composition. • Identifies microbial metabolite alteration (beyond microbiota dysbiosis) as the major UPFs mechanism. • The emulsifiers, modified starches and lipid structures in UPFs work together to destroy microbial metabolism. • Microbiota-directed diets can alleviate gastrointestinal conditions caused by UPFs. In response to the fast-paced lifestyle of modern society, there has been a global surge in the manufacturing and consumption of ultra-processed foods (UPFs). UPFs exert a substantial influence on the modern diet owing to their affordability and extensive availability. The definition of UPFs remains ambiguous, often simplified as "empty calorie" foods, posing challenges in their identification, and resulting in an insufficient understanding of the mechanisms underlying their impact on human health. Recent studies have indicated potential associations between increased intake of UPFs and the occurrence of gastrointestinal conditions. The association between increased intake of UPFs and the development of gastrointestinal disorders was revealed. The effects of components of UPFs on the compositions of gut microbiome were reviewed in detail. Microbiota-directed complementary diets were proposed to alleviate the gastrointestinal conditions caused by UPFs. This review presented new perspectives on the gastrointestinal conditions for increased intake of UPFs, with a specific focus on the gut microbiome. The study also suggested microbiota-directed dietary management for gastrointestinal health.