EVOO supplement prevents type 1 diabetes by modulating gut microbiota and serum metabolites in NOD mice

Aims: Extra virgin olive oil (EVOO) is the highest quality olive oil available and has been shown to regulate postprandial blood glucose in patients with type 1 diabetes (T1D). However, it remains uncertain whether EVOO can prevent the onset of T1D. In this study, we investigated the potential preventive effect of orally administered EVOO on T1D in non-obese diabetic (NOD) mice. Main methods: We analyzed changes in fecal microbes using 16 s rDNA sequencing and serum metabolites using Ultra High-Performance Liquid Chromatography and Quadrupole Time-of-Flight Mass Spectrometry (Q-TOFKey findings: Our findings showed that EVOO supplementation in NOD mice slowed gastric emptying, reduced insulitis, and delayed T1D onset. Moreover, EVOO altered the composition of fecal microbes, increasing the Bacteroidetes/Firmicutes ratio, and promoting the growth of short-chain fatty acids (SCFAs)-producing bacteria, such as Lachnoclostridium and Ruminococcaceae_UCG-005. Moreover, it also increased beneficial serum metabolites, including unsaturated fatty acid and triterpenoid, which positively correlated with the increased SCFAproducing bacteria and negatively correlated with the disease indicators. Conversely, most decreased serum lipid metabolites, such as Oleamide, showed the opposite trend. Significance: Our study demonstrates that EVOO may ameliorate pancreas inflammation and prevent T1D onset in NOD mice by modulating gut microbiota and serum metabolites.