Phenolic-rich extract of olive leaf with a hypocaloric diet alleviates oxidative stress in obese females: a randomized double-blind placebo controlled trial.

BACKGROUND AND AIM

This trial aimed to investigate the effect of the addition of olive leaf extract (OLE) to a standard calorie-restricted diet on serum oxidative stress markers and liver enzymes.

METHODS AND RESULTS

This single-center double-blind, parallel-group, randomized controlled trial was conducted for 8 weeks. Seventy women with obesity (BMI> 30, <40 kg/m2) aged 18 and 50 years were equally assigned to each trial group by randomization. The intervention group received OLE capsules (250 mg olive leaf extract/day), and the placebo group received placebo capsules (250 mg placebo/day) both of them received a calorie-restricted diet. Serum concentration of oxidative stress biomarkers and liver enzymes were assessed at baseline and study endpoint. No significant difference was shown in baseline participant characteristics among the OLE and placebo groups (p > 0.05). At the end of the trial, the OLE group showed a lower concentration of serum malondialdehyde compared to the placebo group (-0.61 ± 0.23 vs -0.48 ± 0.21, p = 0.02), result was also significant after adjustment for confounding factors (p = 0.00). There was, however, no significant difference in serum total antioxidant capacity, Alanine Aminotransferase, Aspartate Aminotransferase, Alkaline Phosphatase, and Lactate Dehydrogenase (p > 0.05).

CONCLUSIONS

Adding OLE to a hypocaloric diet improves oxidative stress more effectively compared with a hypocaloric diet alone in obese women.

TRIAL REGISTRATION

This study was registered in the Iranian Registry of Clinical Trials (IRCT registration number: IRCT20190129042552N2).