The present study aims to examine the effects of three different high-fat diet (HFD) on mice gut microbiota in order to analyse whether they create the microenvironmental conditions that either promote or prevent colorectal cancer (CRC). We evaluated colonic mucosa-associated microbiota in CD1 mice fed with HFD, based on 60% kcal from fat-containing coconut, sunflower or extra-virgin olive oil as the only source of fat. The main findings were as follows: (a) All HFD produced a decrease in the richness and diversity of the intestinal microbiota that was independent of mouse weight, (b) HFD switched Lactobacillus to Lactococcus. In general, the results showed that both sunflower- and coconut-HFD generated a pro-inflammatory intestinal microenvironment. In brief, coconut-HFD decreased Akkermansia and increased Staphylococcus, Prevotella and Bacteroides spp. abundance. Sunflower-HFD reduced Akkermansia and Bifidobacterium, while enhancing Sphingomonas and Neisseria spp. abundance. In contrast, EVOO-HFD produced an anti-inflammatory microenvironment characterised by a decreased Enterococcus, Staphylococcus, Neisseria and Pseudomonas spp. abundance. At the same time, it increased the Firmicutes/Bacteroidetes ratio and maintained the Akkermansia population. To conclude, EVOO-HFD produced changes in the gut microbiota that are associated with the prevention of CRC, while coconut and sunflower-HFD caused changes associated with an increased risk of CRC.
Keywords: Akkermansia; Neisseria; Prevotella; Staphylococcus; bacteroidetes; coconut oil; firmicutes; gut microbiome; inflammation; sunflower oil.