Protective effect of apiaceous vegetables against Total Western Diet- and dextran sulfate sodium-induced colitis in mice

Background Western-style dietary patterns are associated with colitis and colon cancer. Existing data indicate intake of apiaceous vegetables (API; e.g., celery, parsnip) may prevent inflammation-associated diseases. Objective We investigated in mice the effect of API supplementation to the Total Western Diet (TWD) against dextran sulfate sodium (DSS)-induced colitis. Methods Male C57BL/6J mice (8-week-old; 15/group) were fed TWD supplemented with 21% or 42% fresh API (w/w) and given 2% DSS to induce colitis. Diet intake, body weight, and disease activity index (DAI) were monitored. Serum was collected for cytokine/chemokine analysis and colonic tissues for histology and Western blot. Fecal samples were analyzed by 16S rRNA gene sequencing and targeted/untargeted metabolomics. Phenotypic data were analyzed by ANOVA with Tukey’s test. Microbiome data were Centered-Log Ratio (CLR) transformed and analyzed using linear mixed models with adjusted pairwise comparisons. Results API supplementation attenuated colitis phenotypes including weight loss (44% recovery; P < 0.001), colon shortening (57% recovery; P < 0.01), disease activity (59% lower; P < 0.001), cytokine/chemokine release (35-73% reductions; P < 0.05), and mucosal F4/80+ cells infiltration (80% reduction; P < 0.001). API also improved gut microbiota diversity and composition, increasing alpha diversity metrics (4.4%-13.8%; P <0.05), suppressing pathogenic bacteria ( Paraclostridium , Enterococcus , Eubacterium ; estimated CLR difference: –1.8 to –6.7; P < 0.001), and enriching beneficial bacteria ( Lachnospiraceae and Blautia ; estimated CLR difference: +1.6 to +3.0 ; P < 0.05). Furthermore, metabolomics indicated TWD consumption increased arachidonic acid and aliphatic aldehydes (by 109%-510%; P < 0.001), and decreased short-chain and unsaturated fatty acids (by 30%-91%; P < 0.001). API supplementation also mitigated TWD-derived functional metabolites (including bile acids; P < 0.05). Conclusions These data indicate that API intake is beneficial for risk reduction of diseases associated with Western diets. However, further investigations are warranted to determine the mechanism behind these beneficial effects.