Extra virgin olive oil high in polyphenols improves antioxidant status in adults: a double-blind, randomized, controlled, cross-over study (OLIVAUS)

Olive oil polyphenols have been associated with cardiovascular health benefits. This study examined the antioxidant and anti-inflammatory effect of extra-virgin high polyphenol olive oil (HPOO) vs. low polyphenol olive oil (LPOO) in healthy Australian adults.In a double-blind cross-over trial, 50 participants (aged 38.5 ± 13.9 years, 66% females) were randomized to consume 60 mL/day of HPOO (320 mg/kg polyphenols) or LPOO (86 mg/kg polyphenols) for three weeks. Following a 2-week wash-out period, participants crossed-over to the alternate treatment. Plasma oxidized low-density lipoprotein (ox-LDL), total antioxidant capacity (TAC), high-sensitivity C-reactive protein (hs-CRP) and anthropometrics were measured at baseline and follow-up.Fourty-three participants completed the study. Although there were no significant differences between treatments in the total sample, plasma ox-LDL decreased by 6.5 mU/mL (95%CI - 12.4 to - 0.5) and TAC increased by 0.03 mM (95% CI 0.006-0.05) only in the HPOO arm. Stratified analyses were also performed by cardiovascular disease risk status defined by abdominal obesity (WC 94 cm in males, 80 cm in females) or inflammation (hs-CRP 1 mg/L). In the subgroup with abdominal obesity, ox-LDL decreased by 13.5 mU/mL (95% CI - 23.5 to - 3.6) and TAC increased by 0.04 mM (95% CI 0.006-0.07) only after HPOO consumption. In the subgroup with inflammation, hs-CRP decreased by 1.9 mg/L (95% CI - 3.7 to -0.1) only in the HPOO arm.Although there were no significant differences between treatments, the changes observed after HPOO consumption demonstrate the antioxidant and anti-inflammatory effect of this oil, which is more pronounced in adults with high cardiometabolic risk (Clinical Trial Registration: ACTRN12618000706279).