Saturated fats are commonly claimed to raise human blood cholesterols and contribute to cardiovascular disease. Previous literature data were highlighted that although palm oil is 50% saturated, it does not behave like a saturated fat. Human trials were conducted to compare the effects on serum cholesterol levels given by palm olein and monounsaturated oils. It was postulated that saturation/unsaturation of the fatty acids situated at sn-2 positions of triglycerides in the fat molecules determine the induced blood lipid levels but not the overall saturation of oils. The results showed that the lipid parameters (LDL and HDL) effects induced by these oils are similar with no significant differences. This study provides concrete evidence that the unsaturation levels of these oils at sn-2 position of TG are similar (90-100%) which are claimed to be responsible for the lipid parameters. In conclusion, the public negative perception on believing that the overall saturation of oils is detrimental to health should be corrected because in fact the unsaturation at sn-2 positions of the saturated vegetable fat such as palm olein and cocoa butter make them behave like mono-unsaturated oils, unlike saturated animal fats that possess a high content of saturated fatty acids at sn-2 position.
It is not clear whether a saturated fatty acid-rich palm olein diet has any significant adverse effect on established surrogate lipid markers of cardiovascular disease (CVD) risk. We reviewed the effect of palm olein with other oils on serum lipid in healthy adults. We searched in MEDLINE and CENTRAL: Central Register of Controlled Trials from 1975 to January 2018 for randomized controlled trials of ≥2 wk intervention that compared the effects of palm olein (the liquid fraction of palm oil) with other oils such as coconut oil, lard, canola oil, high-oleic sunflower oil, olive oil, peanut oil, and soybean oil on changes in serum lipids. Nine studies were eligible and were included, with a total of 533 and 542 subjects on palm olein and other dietary oil diets, respectively. We extracted and compared all the data for serum lipids, such as total cholesterol (TC), LDL cholesterol, HDL cholesterol, triglyceride, and TC/HDL cholesterol ratio. When comparing palm olein with other dietary oils, the overall weighted mean differences for TC, LDL cholesterol, HDL cholesterol, triglycerides, and the TC/HDL cholesterol ratio were -0.10 (95% CI: -0.30, 0.10; P = 0.34), -0.06 (95% CI: -0.29,0.16; P = 0.59), 0.02 (95% CI: -0.01, 0.04; P = 0.20), 0.01 (95% CI: -0.05, 0.06; P = 0.85), and -0.15 (95% CI: -0.43, 0.14; P = 0.32), respectively. Overall, there are no significant differences in the effects of palm olein intake on lipoprotein biomarkers (P > 0.05) compared with other dietary oils. However, dietary palm olein was found to have effects comparable to those of other unsaturated dietary oils (monounsaturated fatty acid- and polyunsaturated fatty acid-rich oils) but differed from that of saturated fatty acid-rich oils with respect to the serum lipid profile in healthy adults.