Olive oil phenolic compounds decrease the postprandial inflammatory response by reducing postprandial plasma lipopolysaccharide levels

• Phenolic compounds of virgin olive oil (VOO) may prevent the development of atherosclerosis.
• We propose an action mechanism for their anti-inflammatory properties.
• VOO phenolic compounds reduce postprandial lipopolysaccharide (LPS) levels.
• NF-κB was the main transcription factor inhibited by VOO phenolic compounds.
• Postprandial inflammation decreased by a reduction in LPS absorption.

We investigated the molecular mechanisms by which phenolic compounds (phenols) in virgin olive oil reduce the postprandial inflammatory response with the aim of identifying the transcription factor involved and the downstream effects. Olive oil-based breakfasts prepared with virgin olive oil (VOO) with high (398 ppm), intermediate (149 ppm) and low (70 ppm) phenol content were administered to 49 metabolic syndrome patients following a randomized crossover design. The consumption of a high-phenol VOO-based breakfast limited the increase of lipopolysaccharide plasma levels, TLR4, and SOCS3 proteins (p < 0.001, p = 0.041 and p = 0.008, respectively), the activation of NF-κB (p = 0.016) and the IL6 (p = 0.007 and p = 0.048, low and intermediate oil, respectively), IL1B (p = 0.002, intermediate oil), and CXCL1 (p = 0.001) postprandial gene expression, in peripheral blood mononuclear cells, as compared with the consumption of a breakfast prepared with the same oil but with low or intermediate phenol content. Virgin olive oil phenolic compounds reduce the postprandial inflammatory response in association with postprandial plasma lipopolysaccharide levels.