09/10/2007 (NutraIngredients.com) - A diet rich in crude palm oil, different from the refined industrial oil, may reduce blood levels of very LDL-C and triacylglycerol in healthy, young individuals, Brazilian researchers report.
The study, published on-line in the Elsevier journal Nutrition, adds to the debate on palm oil and heart health - a controversial topic with conflicting reports in the literature on the efficacy and health profile.
The controversy is centred on the saturated fat content of palm oil, with almost half of the oil composed of palmitic oil, a C16:0 saturated fatty acid. However, researchers have noted that the nature of the oil may affect the cholesterol-influencing properties. In crude palm oil, the palmitic acid is attached to the glycerol molecule in the alpha position instead of the beta-position, as is observed in butter - a fat with known cholesterol-raising activity
The new study, by researchers from the Bahia Foundation for the Development of Sciences, the Federal University of Bahia Medical School, and the Bahian Hypertension and Atherosclerosis League, looked at the effect of a crude palm oil-rich diet on the blood lipid levels of 34 young individuals (average age 21.9).
The subjects (average BMI 22.0 kg per sq. m), consumed 10 millilitres of previously boiled crude palm oil after lunch or dinner once a day for two weeks. At the end of the study, the researchers report that all lipid fractions decreased, with a mild, statistically significant 11.5 per cent decrease in concentrations of vLDL-cholesterol and triacylglycerol.
"This study offered an opportunity to observe the influence of the daily consumption of boiled crude palm oil on the lipid profile of young and healthy non-dyslipidemic subjects," wrote lead author Ana Marice Ladeia.
"It is important to point out that the methodology of this study tried to reproduce the amount and conditions in which crude palm oil is consumed with common foods typical of Bahian cuisine and its African traditions," she added.
The researchers also noted gender-specific effects, with men showing a mildly significant rise in LDL-cholesterol levels (18 per cent), while females showed a mildly significant drop in all blood lipid levels, except for HDL-cholesterol.
The mechanism for the lipid-lowering effects of the crude palm oil may depend on multiple factors, said the researchers, including the attachment of plamitic acid to glycerol.
They also added that crude palm oil is a very rich source of vitamin E, beta-carotene, and tocotrienols, previously reported to have cholesterol-lowering effects.
"The data of the present study reinforce the evidence that palm oil cannot be classified as a cholesterol-raising oil," wrote Marice Ladeia.
"Plasma lipid response to a palm oil-rich diet was found to be mild in intensity and appeared to be dependent on variables such as age, gender, increased BMI, daily cholesterol ingestion, and the crude, refined, or synthetic nature of the oil consumed.
"Furthermore, scientific evidence of palm oil as an atherogenic edible oil for humans is still lacking and awaits further well-designed studies," she concluded.
Source: Nutrition (Elsevier)
Published on-line ahead of print, doi:10.1016/j.nut.2007.08.013
"A palm oil-rich diet may reduce serum lipids in healthy young individuals"
Authors: Ana Marice Ladeia, E. Costa-Matos, R. Barata-Passos and A. Costa Guimaraes