Background: Recycling cooking oil for deep frying makes the oil more vulnerable to lipid peroxidation that generates oxidative com-pounds, linking to an increased risk of cardiovascular diseases. The study aimed to investigate the long-term effect of recycled deep-frying oil on blood pressure and aortic structure in rats.
Methods: Adult male Sprague-Dawley rats were divided into four groups, namely (a) control; (b) fresh oil (FO); (c) deep-frying oil (DO); and (d) recycled deep-frying oil (RDO). Feeding duration was six months. Blood pressure was measured at baseline and the end of the study using tail-cuff method. After six months the rats were sacrificed and aortic arches were obtained to quantitate intimal and media thickness as well as to examine pathological changes.
Results: Both FO and DO groups did not show any significant blood pressure and aortic microscopic structure. There was a significant increase in blood pressure in rats fed RDO compared to other groups. Aortic media thickness was significantly increased in RDO group, while intimal thickness did not differ among the groups. Microscopic examination showed an enlarged space between elastic lamellae in aorta of RDO group.
Conclusions: Long-term intake of food containing recycled deep-frying oil causes blood pressure elevation and vascular hypertrophy in rats.