Oil for Life to Balance omega-3 polyunsaturated fatty acids ... - Oil4Life

� sterols: β-sitosterol (24-ethyl-�5-cholestene-3β-ol) is the main component of this fraction.
Other sterols, stigmasterol and campesterol, are also present;
� hydroxy triterpenic acids: oleanolic, maslinic, ursolic and its deoxy and 2α-hydroxy
derivatives are well represented; due to their chemical structures, these compounds should
be good candidates for biological and nutritional investigations; up to now little research
has been done on this interesting subject;
� olives contain a large amount of water, the so-called “vegetation water”: which is
squeezed out together with the oil and is usually removed by centrifugation. Vegetation
water contains sugars, nitrogen derivatives, organic acids, pectin, salts, polyhydroxy
compounds and phenol derivatives. These compounds are mainly present as
glycoconjugates; one of them, oleoeuropeine, is typical of olive oil and is the precursor of
bioactive phenols (see below). Some of these molecules, which are of amphiphilic nature,
are distributed between the organic and aqueous phases as the oil is processed. Those
retained in the oil phase are important because they favourably protect the stability of
virgin oil against oxidation. From the vegetation water, the following components were
extracted and identified: β(4-hydroxyphenyl) ethanol, β(3.4 dihydroxy-phenyl)ethanol and
o-hydroxyphenol.
7.1 Digestion and absorption of olive oil triglycerides
Fat digestibility depends upon the chain length and the structure and distribution of fatty
acids in the triglyceride molecule. Triglycerides with lower melting points are digested and
absorbed more rapidly; the rate of hydrolysis is hindered by the presence of saturated fatty
acids and fostered by the unsaturated ones. The presence of oleic acid in the 2 position of
many 2-monoglycerides results in a better stabilization of emulsion which can penetrate
more easily into the intestinal mucosa (Viola P. et al., 1975). As a consequence, olive oil is
better hydrolyzed than some other dietary fats. Fatty acids and the 2-monoglycerides are
absorbed from the intestinal mucosa cells by free diffusion, due to the linkage of fatty acids
to a fatty acid binding protein, which allows their intracellular transport to the endoplasmic
reticulum where they are activated and reesterified by a specific synthase. The activity of this
enzyme is induced by oleic acid. These results together warrant the assumption of very high
digestibility of olive oil both in laboratory animals and in humans (Berra B. et al., 1996).
7.2 Use of Olive Oil for Secondary Prevention of Atherosclerosis
The amount and type of dietary fats play a crucial and well-documented role on plasma lipid
concentration (Ahrens E.H. et al., 1957, Keys A. et al., 1957). In particular, diets with highly
polyunsaturated fats have been suggested for the prevention and treatment of atherosclerosis.
WHO recommended considering usual nutritional habits, which should not be changed
abruptly (Organization Mondiale de la Santè, 1982). This aspect is particularly important in
Mediterranean countries, where the population was induced to move from a diet based on
olive oil to a new one in which corn oil represented the main fat. Polyunsaturated fatty acids
(PUFA) abundant in corn oil as well as other vegetable fats were found, on the basis of
epidemiological studies, to decrease plasma cholesterol and low density lipoproteins
(Vergroesen A.J., 1975). The mechanism whereby PUFA administration results in lowering
plasma lipid levels is still questionable, despite the many experiments made on this topic
(Connor W.E. et al., 1982). Moreover, nowadays linoleic acid seems to be atherogenic if
assumed in large amounts (Tobarek M. et al., 2002); diets rich in polyunsaturated fats may
entail other harmful effects, such as formation of cholesterol gallstones (Grundy S. M.,
1975), increased vitamin E requirements and promotion of obesity.
For these discrepancies and according to the WHO recommendations, we evaluated the
variations induced on plasma lipid levels by changing the dietary fat composition from corn
27