(P21-021-24) Plant Based Meat Increases Colitis Severity and Tumorigenesis Relative to Other Protein Sources in Mice Fed the Total Western Diet

Objectives: We have shown previously that mice fed the Total Western Diet (TWD) which emulates the Western dietary pattern for both macro and micronutrient content have increased colitis, gut inflammation and tumorigenesis relative to mice fed a healthy control diet (AIN93G). In these previous studies we have exclusively used casein as the TWD protein source, the objective of the current study was to test the effects of different dietary protein sources in the TWD on gut health.

Methods: Male, 5-week-old, C57BL6 mice were fed the following diets ad lib. for 14 weeks: 1) AIN93G, a control diet with casein as the protein source; 2) the Total Western Diet (TWD-CW), with a dairy protein source (80% casein, 20% whey); 3) TWD-GB, ground beef as the protein source; 4) TWD-PBM heme-containing, soy derived plant-based meat (PBM) as the protein source; 5) TWD-Soy, isolated soy protein as the protein source (n=36/group). All diets except for AIN93G, were formulated to contain the same amount of fiber and macro and micronutrients and only differed by protein source. After 14 days on treatment, colon tumorigenesis and colitis were induced by azoxymethane injection and 1% dextran sodium sulfate inclusion into the drinking water for 10 days.

Results: As expected, mice fed the AIN93G diet had lower colitis disease activity index scores (DAI) relative to all TWD based diets at the active colitis timepoint (P >0.001, day 24). Mice fed the TWD-GB diet had lower DAI scores than all of the other TWD treatment groups (P > 0.05). At colitis recovery (Day 38), DAI scores were not significantly different among the TWD-GB, TWD-Soy, and AIN93G groups. However, TWD-PBM fed mice had higher DAI scores relative to all other treatments (p < 0.0001). Mice fed the AIN93G diet had fewer tumors compared to the TWD-based diets (P >0.01). However, total tumor burden was higher in mice fed the TWD-PBM diet compared to counterparts fed the AIN93G and TWD-GB diets (P >0.01).

Conclusions: These data suggest that in the context of a Western diet, PBM may increase gut inflammation and tumorigenesis relative to other protein sources. Mice fed the TWD-Soy diet had a similar phenotype to the other TWD diets, suggesting something other than soy protein, such as added heme in PBM may be driving these harmful effects.

Funding Sources: Utah Agricultural Experiment Station, Build Dairy Inc.