Background and aims: Paraoxonase is a HDL related enzyme, which seems to have roles in antioxidant protection in the human body. The present study was set with the aim of investigating the effects of DASH diet, rich in antioxidants, on paraoxonase enzyme activity in obese or overweight women.

Methods: This study is a randomized parallel controlled trial, carried out on 44 (22 intervention and 22 control) healthy overweight and obese women in Isfahan. The intervention period consisted of 3 months of a control or a DASH diet. Diet adherence, anthropometric parameters and blood pressure were checked every 2 weeks. Paraoxonase activity, phenylacetate of paraoxonase was analyzed at the beginning and end of the trial. The data were analyzed using SPSS software. P≤0.05 was considered statistically significant.

Results: No significant change was observed in paraoxonase activity or phenylacetate of paraoxonase between two groups (P=0.26 and P=0.13). Besides, The DASH diet resulted in significant decrease in BMI and Waist circumference (P=0.03 and P=0.01, respectively) but fasting blood sugar, total cholesterol and LDL cholesterol changes were not statistically significant in both groups.

Conclusion: It is likely that paraoxonase activity do not change in response to DASH diet. However, the effects of nutritive factors on activity of this enzyme need further studies.