The effect of chronic consumption of fresh and heated red palm oil (RPO) on lipid profile and lipid peroxidation was investigated. 30 male rats were divided into 3 groups, each prescribed with the following food for 20 weeks, 15% weight/weight (w/w) fresh red palm oil (fRPO), 15% w/w heated once red palm oil (1RPO) and heated 5 times red palm oil (5RPO). MDA level was determined as described by Ledwozyw et al., lipid profile by Boehringer Mannheim diagnostic kit and LDL by calculation with Friedwald et al. formula. The results showed that the concentration of MDA increased significantly (p<0.05) in all 3 groups when compared with baseline concentration. However, there was no significant difference of MDA concentration between the 3 groups during the course of treatment. There was a significant decrease (p<0.05) of total cholesterol (TC) concentration in fRPO group, 1RPO and 5RPO group after 20 weeks of treatment. There was no significant difference of TC concentration between the 3 groups after 20 weeks of feeding. As for triacylglycerol concentration, there were no significant changes in all 3 groups after 20 weeks of treatment. Whereas the HDL concentration decreased significantly (p>0.05) on the twentieth week in fRPO group when compared with baseline concentration. The HDL concentration of 1RPO group and 5RPO group did not show any significant difference with baseline concentration on the twentieth week. There was no significant difference of HDL concentration between all 3 groups at the end of study. LDL concentration in 5RPO group showed significant increase (p<0.05) after 16 week of feeding when compared with baseline concentration and with fRPO and 1RPO group in the same week. Ratio of TC/HDL in 5RPO group increased at the beginning of feeding but it fell back to baseline level at the end of the study. There was no significant difference in the ratio of TC/HDL between all 3 groups after twenty weeks. In conclusion, both flesh and heated RPO appeared comparable in their effect on serum cholesterol and lipid peroxidation. It appears that long term feeding with fresh and heated RPO did not have an adverse effect on serum TG, HDL and TC/HDL ratio. However, it appears that prolonged heating increases LDL cholesterol level. Further studies are required to ascertain whether the increase in LDL cholesterol and MDA with heated oil would render it more atherogenic.
