BARCELONA, Spain—A recent Spanish study found the inverse relationship of the phenolic metabolites in two different olive oils with the degree of low-density lipoprotein (LDL) oxidation supports the in vivo antioxidant role of olive oil phenolics compounds (J Nutr. 2010;140(3):501-08).Researchers examined how the ingestion of two similar olive oils affected the content of the metabolic forms of olive oil phenols in LDL in men. The oils differed in phenol concentrations as follows: high (629 mg/L) for virgin olive oil (VOO) and null (0 mg/L) for refined olive oil (ROO). The study population consisted of a subsample from the EUROLIVE study and a randomized, controlled, crossover design was used.
The levels of LDL hydroxytyrosol monosulfate and homovanillic acid sulfate, but not of tyrosol sulfate, increased after VOO ingestion (P<0.05), whereas the concentrations of circulating oxidation markers, including oxidized LDL (oxLDL), conjugated dienes and hydroxy fatty acids decreased (P<0.05). The levels of LDL phenols and oxidation markers were not affected by ROO consumption. The relative increase in the three LDL phenols was greater when men consumed VOO than when they consumed ROO (P<0.05), as was the relative decrease in plasma oxLDL (P=0.001) and hydroxy fatty acids (P<0.001). Plasma oxLDL concentrations were negatively correlated with the LDL phenol levels (r = –0.296; P=0.013). Phenols in LDL were not associated with other oxidation markers. In summary, the phenol concentration of olive oil modulates the phenolic metabolite content in LDL after sustained, daily consumption.
