The effect of meals rich in thermally stressed olive and safflower oils on postprandial serum paraoxonase activity in patients with diabetes.Eur J Clin Nutr 2001; 55(11):951-8EJ
To determine the effects of meals rich in thermally stressed safflower (TSAF) and olive (TSOL) oils on postprandial serum paraoxonase (PON1) arylesterase activity and low density lipoprotein (LDL) oxidation in patients with type 2 diabetes.
A randomised cross-over study.
Diabetes clinic and general practice.
Fourteen patients (six men and eight women) with type 2 diabetes, aged 48-67 y, glycated haemoglobin <10% and fasting blood glucose <11 mmol/l were recruited.
Patients received a milkshake rich in TSAF or TSOL and at least a week later they received the alternate milkshake. These fats contained high levels of lipid oxidation and degradation products. Blood samples were taken fasted and 4 h after consumption of the milkshake.
MAIN OUTCOME MEASURES
Serum PON1 activity and lag time in LDL oxidation.
After the meal rich in TSOL, serum PON1 activity increased significantly in women (12 (2.22) micromol/ml/min, mean (95% confidence interval), P=0.03) and not in men (0 (-4.4) micromol/ml/min) during the postprandial period. The increase in PON1 activity after the TSOL meal was significantly (P=0.03) greater in women compared with men. In women, the increase in serum PON1 activity after the TSOL meal was significantly different (13 (1.25) micromol/ml/min, P=0.04) compared with the corresponding change (-1 micromol/ml/min) after the TSAF meal. The lag time in LDL oxidation and indices of oxidative stress and antioxidant capacity did not vary significantly during the meals.
Meals rich in TSOL may increase postprandial serum PON1 activity in middle-aged and older diabetic women. This change is potentially anti-atherogenic and may favour the use of olive oil over polyunsaturated fats in the diet of patients with type 2 diabetes.
The study was supported by a grant from the National Heart Foundation of New Zealand.