• Calories and Vitamins
Palm oil, like all other oils and fats, provides 9
kcal g-1 compared with 4 kcal each for protein
and carbohydrates (1 kcal = 4.18 kJ). Fats are
also a source of vitamin A, D and E and act as
carriers of these and of vitamin K in the human
body. Crude palm oil is a rich source of pro-
vitamin A, in the form of carotenoids (500-700
mg kg-1), and refined red palm oil is used for
the treatment and prevention of vitamin A
deficiency in many countries.
• Digestibility
It has been shown long ago that there is no
significant difference in the digestibility of
different fats; only those with very high melting point (above 50°C) exhibiting somewhat lower digestibility. It has also been shown that it is the melting point of the whole fat that matters -not its individual components.
Fats, of course, enrich the flavour, taste and
texture of food and make it more palatable.
Unsaturation and Essential Fatty Acids Palm oil is a balanced oil containing equal amounts of saturated and unsaturated acids (Table 34). Its component fatty acids consist of approximately:
50% saturated (mainly palmitic acid);
40% monounsaturated (mainly oleic acid); and
10% polyunsaturated.
Palmitic acid, though saturated, is neutral and
does not raise blood cholesterol level. The
polyunsaturated fatty acid content in palm oil is linoleic acid [C18:2 (n-6)], which is essential in human and animal nutrition.
• Cholesterol
Like all vegetable oils, palm oil is virtually
cholesterol-free. Cholesterol, being a product of animal metabolism, is present in varying
amounts in animal fats (e.g. butter 3150 mg
kg-1, lard 3500 mg kg-1, beef fat 1100 mg kg-1), but is virtually absent in oils and fats of
vegetable origin.
•• DISEASES OF AFFLUENCE
The greatest killer diseases of present times,
especially in the developed countries, are heart disease and cancer. Both of them are influenced to varying extents by diet and so the role of fats in this respect is discussed at greater length below.
Palm Oil and Cardiovascular Disease Palm oil, being composed of equal proportion of
saturated and unsaturated fatty acids with a
sufficient amount of essential fatty acid, is easily digested and absorbed. Human clinical studies have shown that it does not raise serum cholesterol levels, and in this respect, it is comparable to olive and canola oils.
MPOB and other researchers have reviewed the effects of the major fatty acids in palm oil and found that they had no hypercholesterolemic effects.
On the contrary, a diet containing palm oil increases the HDL-cholesterol, thereby reducing the LDL-C/ HDL-C ratio. This observation has been confirmed by reports of normal plasma cholesterol levels and low incidence of coronary heart disease in populations consuming palm oil on a daily basis.
Antioxidants in Palm Oil Free radicals have been implicated in heart disease and the oxidation of LDL-C, and lipids enhance the development of atherosclerosis.
Peroxidation of polyunsaturated fatty acid
generates free radicals. Antioxidants in palm oil like the carotenoids and vitamin E can neutralize free radicals and so prevent the oxidation of LDL- C. Recently, there has been a recommendation for an increased intake of antioxidants as a way of reducing the incidence of atherosclerosis and ischaemic heart disease.
• Trans Fatty Acids
Trans fatty acids are produced during the
industrial hydrogenation of oils, particularly
those with large proportions of polyunsaturated fatty acids. They are now recognized as a significant risk factor for coronary artery disease since they are associated with the increased total and LDL-cholesterol, and reduced HDL- cholesterol levels.
The use of palm oil for margarine and shortening formulations helps to reduce the level of, or even eliminate trans fatty acids and the associated risks to health, besides eliminating costly hydrogenation.
Following the mandatory labeling of trans fatty acid in some countries, palm oil, which is naturally semi-solid at room temperature, has been considered as one of the most suitable replacements for hydrogenated fats in many food formulations.
Published by Olusola salau
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