Arterial pressure and lipid profile in rats following chronic ingestion of palm oil diets.

The mean arterial blood pressure (MAP) and plasma lipid profile of rats following chronic consumption of a diet containing 15% palm oil (fresh or oxidized) were studied. Rats were allowed to feed on either a fresh or oxidized palm oil diet for 18 weeks and their effects were compared with a control group receiving normal rat feed. Mean arterial blood pressures were 128.0 +/- 2.3 mmHg (mean +/- SEM) for the control, 135.0 +/- 2.4 mmHg for the fresh-oil fed group and 147 +/- 2.5 mmHg for the oxidized oil-fed group. The oxidized oil-fed group had a significantly greater rise in mean arterial blood pressure than the control and fresh oil-fed groups (P < 0.01 and 0.05, respectively). Mean arterial blood pressure was not significantly elevated in the fresh oil-fed group than the control. Low density lipoprotein cholesterol (LDL) levels were 1.51 +/- 0.07 mMol/L for the control, 1.62 +/- 0.03 mMol/L for the fresh oil-fed group and 1.78 +/- 0.03 mMol/L for the oxidized oil-fed group. The values were not significantly different in the control and the fresh oil groups. LDL level was significantly higher in the oxidized than in the control (P < 0.01) and fresh oil-fed groups (P < 0.05). Total cholesterol for the two test groups were significantly (P < 0.05) higher than the control, while the value in the oxidized oil group was also significantly (P < 0.05) higher than the fresh oil-fed group. There was no significant difference in high density lipoprotein cholesterol (HDLP) levels in the three groups. The significantly elevated MAP in the oxidized oil-fed rats when compared to the fresh oil-fed and control rats may be due to thermoxidation of the fresh oil that produced significantly higher levels of LDL and total cholesterol which predisposes to high blood pressure.