Olives and Olive Oil - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 505

The following details the nutritional properties and major
benefits of olive oil from various points of view.

immunosuppressive agent. Specifically, diets that contain
olive oil as an ingredient significantly reduce production of
lymphocytes (Yaqoob et al., 1994), modify the production
of interleukins (de Pablo et al., 1998) and reduce the
activity of natural killer cells (de Pablo et al., 2004).
Another interesting effect of a diet that contains olive oil
lies in the decrease of the expression of adhesion molecules
(Sanderson et al., 1995); their importance lies in their
involvement in functions such as the development of
atherosclerotic plaque. Finally, epidemiological studies
have shown the beneficial role of olive oil in reducing
inflammatory processes. Specifically, it has been reported
that the consumption of olive oil improves symptoms
of rheumatoid arthritis by altering the production of
inflammatory response mediators (Linos et al., 1999). It
seems that this action may be mediated by the production
of eicosatrienoic acid.

Cardiovascular diseases
It is generally accepted that consumption of olive oil
reduces the risk of coronary artery disease (CAD), mainly
at three levels (Zampelas and Kafatos, 2004). First, several
intervention studies have shown that mainly due to its
MUFA composition, olive oil reduces cholesterol levels
and possibly increases levels of plasma HDL cholesterol
(Williams et al., 1999). Second, it is known that olive oil
has beneficial effects against oxidation of LDL. To wit, it
has been shown that PUFAs increase the oxidation of LDL
to a greater degree when compared to MUFAs (Hargrove
et al., 2001). Additionally, the composition of olive oil
antioxidants such as vitamin E, polyphenols (flavonoid
type), and squalene increases its resistance to oxidation
(Visioli and Galli, 2002). Last, the antithrombotic prop-
erties of olive oil have also been demonstrated since it
reduces levels of thrombogenic factors in plasma such
as factor VII and the plasminogen activator inhibitor-1
(L opez-Segura et al., 1996; Roche et al., 1998).

Oxidative stress
There are more and more degenerative pathologies that are
involved in one way or another with the excessive forma-
tion of free radicals. For this reason, nutritionists, clini-
cians, epidemiologists, and other professionals encourage
an increase in the intake of antioxidants in our diet such
as the polyphenols present in olive oil. Specifically, it has
been shown that both oleuropein and hydroxytyrosol inhibit
LDL oxidation (Visioli and Galli, 1994; Visioli et al., 1995)
as well as effectively scavenge superoxide anions generated
by human polymorphonuclear cells (Visioli et al., 1998).
In parallel, a protective effect of hydroxytyrosol has been
described toward hydrogen peroxide-induced damage to
human erythrocytes (Manna et al., 1999). The mechanism
of action of polyphenols in olive oil is related to its o -
diphenol structure, which increases radical stability (Visioli
et al., 1998).

Cancer
Unlike diets rich in PUFAs (n-6), diets rich in MUFAs are
associated with a reduced risk of certain types of cancer
(L opez et al., 2004). However, sometimes the epidemio-
logical data do not match with the experimental data. In
terms of breast cancer, a cohort study (Sieri et al., 2004)
suggested that a diet rich in vegetables and olive oil protects
against this type of cancer. However, the protective action
of olive oil lies not only in its fat composition but also in the
composition of its minor components such as polyphenols.
Owen et al. (2000) have suggested that polyphenols present
in olive oil play an important role in the prevention of col-
orectal cancer due to the demonstrated inhibitory effect of
polyphenols against free radical generation in fecal matter.
Phytosterols are other components of the oil that are as-
sumed to be anticancer compounds (Moreno, 2003) since it
has been shown that ß-sitosterol inhibits tumor invasion and
cell growth by 70% in human breast cancer cells (Award
et al., 2001). The effect of tocopherols (present in olive oil)
in inhibiting cancer cell growth has been studied (Gynsin
et al., 2002) both in prostate cancer and colon cancer. All
of them show significant levels of cell inhibition.

Clinical nutrition
The healthy properties of olive oil have led to its use as a
lipid component within the parenteral and enteral nutrition
formulas as a routine practice in hospitals. Beneficial ef-
fects have been proven from the inclusion of olive oil in
the enteral nutrition of patients with diabetes mellitus and
inflammatory intestinal disease (Middleton et al., 1995;
Mangas-Cruz et al., 2004). Meanwhile, the use of olive
oil during parenteral nutrition is due to various beneficial
effects in patients, such as increasing vitamin E levels in
the plasma of traumatized patients (Reimer et al., 2000),
lowering PGE2 levels (associated with activation of the
immune system that mitigates the effects of possible infec-
tions through catheter), and finally, because of its ability to

Immune system
It is currently assumed that the role olive oil may play in the
immune system is due mainly to the presence of oleic acid
(de Pablo et al., 2004), which in most situations acts as an