25/10/2007 (Nigerian Tribune) - The palm oil and the blood cholesterol controversy may have been put to rest with scientists from Brazil declaring that a diet rich in crude palm oil may reduce LDL (bad) cholesterol and triacylglycerol in healthy, young individuals.

However, the researchers noted that the nature of the oil may affect the cholesterol-influencing properties. It added that 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 study, published on-line in the Elsevier journal Nutrition, by researchers from the Bahia Foundation for the Development of Sciences, the Federal University of Bahia Medical School, and the Bahian Hypertension and Arteriosclerosis 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 reported that all lipid fractions decreased, with a mild, statistically significant 11.5 per cent decrease in concentrations of vLDL-cholesterol and triacylglycerol.

According to Ana Marice Ladeia, the lead author, the study tried to reproduce the amount and conditions in which crude palm oil is consumed with common foods typical of Bahian and African cuisine so as to observe the influence of the daily consumption of boiled crude palm oil on the lipid profile of young and healthy subjects with normal blood cholesterol level.

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 (good) cholesterol. Marice Ladeia said “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.”

Though the mechanism for the lipid-lowering effects of the crude palm oil may depend on multiple factors, including the attachment of palmitic acid to glycerol, they said, “ the present study reinforces the evidence that palm oil cannot be classified as a cholesterol-raising oil,”

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. For palm oil to be classified as an edible oil that contributes to thickening of blood vessels, she said, will require more scientific evidence in humans.

For many years now, it has been established that the primary cholesterol-elevating fatty acids are the saturated fatty acids such as lauric, myristic and palmitic acids that simultaneously increase the risk of coronary heart disease. Monounsaturated fatty acids such as oleic acid is as effective in reducing low-density lipoprotein (LDL) cholesterol levels as polyunsaturated fatty acids such as alpha-linoleic acid.

The World Health Organisation in its report stated that there is convincing evidence that palmitic oil consumption contributes to an increased risk of developing diseases of the heart and blood vessels. In a response to the report, the Malaysian Palm Oil Promotion Council cited a study in China comparing palm, soybean, peanut oils and lard (all of which contain saturated fat) that showed that palm oil increased the levels of good cholesterol and reduced the levels of bad cholesterol in the blood. An older study by Hornstra in 1990 also supported the claims of the Malaysian Palm Oil Promotion Council.

A study by the Departments of Agricultural, Food and Nutritional Science and Medicine, University of Alberta equally showed that palmitic acid do not raise blood LDL cholesterol level if intake of linoleic acid was greater than 4.5 per cent of energy. However, if the diet contained trans fatty acids, LDL cholesterol increases and HDL cholesterol decreases.

The studies supporting the Malaysian Palm Oil Promotion Council only addressed the issue of the effect of palm oil on blood cholesterol levels and not its total effect regarding cardiovascular diseases though. An independent group of nutrition, medical and manufacturing experts who examined the oil’s functionality in food products and possible impacts on consumer health during a roundtable discussion also declared that the scientific data on saturated and trans fats found in oils like palm oil to be inconsistent and believed saturated fats were better than people were making them out to be.

Palm oil is a natural source of vitamin E, vitamin K and dietary magnesium. Among the touted health benefits of palm oil, are
• As a rich source of betacarotenes, (about 15 times more than in carrots), it enhances eye health, acts as biological antioxidants protecting cells and tissues from the damaging effect of free radicals such as skin ageing and cancer. The carotenoid enhances immune function by a variety of mechanisms and improve cardiovascular health too.
•Since it is high in tocotrienols, a natural vitamin E, it lowers blood cholesterol levels, by reacting with certain enzymes in the liver that produce cholesterol.