- Olive (Olea europaea) Oil
- Biological Activity
Re: Olive Oil's Active Components and Benefits, A Review
Waterman E, Lockwood B. Active components and clinical applications of olive oil. Altern Med Rev. 2007;12(4): 331-342.
europaea) oil is a major component of the Mediterranean diet, which is
associated with a reduced risk for chronic diseases including heart disease and
cancer. Research suggests that the type of fat consumed "is more important
than the total amount consumed." The relatively high levels of
monounsaturated fatty acids (MUFA) and antioxidants found in olive oil, the
main energy source in the Mediterranean diet, may be at least partially
responsible for its protective effect against degenerative diseases.
contains about 70% oleic acid, a MUFA. Studies on the health benefits of oleic
acid have produced mixed results, but it may protect against the development of
cancer. One in vitro study indicates that oleic acid acts synergistically with
the cancer drug trastuzumab against cell cultures that over-express the
Olive oil also
contains phenolic compounds that provide health benefits. These compounds are
found in higher levels in extra virgin olive oil compared to refined olive oil.
The phenolic compounds hydroxytyrosol and oleuropein are antioxidants that
scavenge free radicals and prevent oxidation of low-density lipoprotein (LDL) cholesterol,
which prevents the development of atherosclerotic plaques. Olive oil itself has
a higher antioxidant capacity than most seed oils, and extra virgin olive oil
has a greater antioxidant capacity than refined olive oil. The phenolic
compounds in olive oil "are capable of scavenging free radicals produced
in the fecal matrix, which is thought to explain the epidemiological data
suggesting a colonic chemopreventative effect of olive oil."
Squalene is a
triterpene that is found in relatively high levels in olive oil and the
Mediterranean diet. The lower incidence of skin cancer in populations that
consume the Mediterranean diet is believed to be due to the effects of
squalene, which has been shown to inhibit skin carcinogenesis in animal
studies. Squalene has also been shown to inhibit HMG-Coa reductase, an
important enzyme in cholesterol synthesis. Acute administration of squalene
increases the rate of cholesterol synthesis. Studies on chronic administration
of squalene have produced conflicting results, including increased, decreased,
and unchanged cholesterol levels. These conflicting results may be
dose-related. Heating and storing olive oil affects its chemistry.
Conventionally heating olive oil results in a time-dependent loss of the beneficial
phenolic compounds. Studies on microwave cooking have produced mixed results;
however, the length of time seems to have major effect on degradation of its
constituents. Olive oil has relatively high levels of MUFAs and low levels of
polyunsaturated fatty acids (PUFAs) compared with other cooking oils.
Therefore, it is less susceptible to lipid peroxidation, which is associated
with cancer and cardiovascular disease. In addition, the antioxidants found in
olive oil prevent lipid peroxidation during long-term storage, and they prevent
the formation of carcinogenic heterocyclic amines during frying.
antioxidants found in olive oil may contribute to the reduced risk of coronary
heart disease and hypertension associated with the Mediterranean diet. Research
indicates that olive oil has antihypertensive effects. One study shows that
individuals with high blood pressure can reduce reliance on antihypertensive
drugs if they consume a diet rich in olive oil. The mechanism of action for
this antihypertensive effect is not clear. Several mechanisms have been
suggested including action as a calcium channel antagonist like the drug
verapamil, improvement of endothelial function, decrease of vascular tone, and
changes in the fatty acid and phospholipids composition of the aorta.
antioxidants found in olive oil and the fruits and vegetables in the Mediterranean
diet are associated with a decreased cancer risk. Hydroxytyrosol prevents cell
damage, blocks cell cycle progression, and induces apoptosis. Pre-clinical studies
show that oleuropein has antiangiogenic effects, disrupts actin filaments thus
disrupting cancer cells, and inhibits cell growth, motility, and invasiveness.
One in vivo study has shown that oleuropein has anti-tumor effects. Olive oil
may also protect against cancer by replacing saturated animal fats and
polyunsaturated plant fats, which are associated with various types of cancer.
In vitro studies indicate that virgin olive oil phenolic compounds have
anti-cancer effects against colorectal carcinogenesis at all three stages.
Phenolic glycosides and oleic acid are stored in the body's fatty tissues,
which may prevent breast cancer by reducing lipid peroxidation in the
phospholipid bilayer of breast tissue. Case control studies indicate an inverse
relationship between olive oil and breast cancer, as well as high mammographic
breast density, a risk factor for breast cancer. In vitro studies show that
several constituents of olive oil have antimicrobial activity against bacteria
associated with intestinal and respiratory infections. In addition, phenolic
compounds in virgin olive oil are active against Helicobacter pylori,
which is associated with gastric ulcers and gastric cancer. The research
suggests that virgin olive oil may prevent H. pylori infections, but in
vivo research is needed to confirm this action and to elucidate the mechanism
effect of olive oil has been found to reduce the inflammation associated with
rheumatoid arthritis. Olive oil also appears to act synergistically with
Omega-3-fatty acids to reduce the symptoms of rheumatoid arthritis. In
addition, consumption of olive oil protects against the development of
The authors conclude
"The evidence indicates…that olive oil and its components contribute
significantly to the health benefits of the Mediterranean diet, with more of an
effect on prevention than treatment." —Marissa N.