Gastrointestinal fate of proteins from commercial plant-based meat analogs: Silent passage through the stomach, oxidative stress in intestine, and gut dysbiosis in Wistar rats.

Plant-based meat analogs (PBMAs) are common ultra-processed foods (UPFs) included in the vegan/vegetarian diets as presumed healthy alternatives to meat and meat products. However, such health claims need to be supported by scientific evidence. To gain further insight into this topic, two commercial UPFs typically sold as meat analogs, namely, seitan (S) and tofu (T), were included in a cereal-based chow and provided to Wistar rats for 10 weeks. A group of animals had, simultaneously, an isocaloric and isoprotein experimental diet formulated with cooked beef (B). In all cases, experimental chows (∼4 kcal/g feed) had their basal protein concentration increased from 14% to 30% using proteins from S, T, or B. Upon slaughter, in vivo protein digestibility was assessed, and the entire gastrointestinal tract (digests and tissues) was analyzed for markers of oxidative stress and untargeted metabolomics. Metagenomics was also applied to assess the variation of microbiota composition as affected by dietary protein. Diets based on PBMAs showed lower protein digestibility than those containing meat and promoted an intense luminal glycoxidative stress and an inflammatory intestinal response. The fermentation of undigested oxidized proteins from T in the colon of Wistar rats likely led to formation of mutagenic metabolites such as p-cresol. The presence of these compounds in the animal models raises concerns about the potential effects of full replacement of meat by certain PBMAs in the diet. Therefore, future research might target on translational human studies to shed light on these findings.