Olive Oil's Heart-Healthy Secret
Phenolic Compounds in Olive Oil May Explain Mediterranean Diet's Benefits
WebMD News Archive
Nov. 11, 2005 - An ingredient found in olive oil may be largely responsible
for the heart-healthy benefits attributed to the Mediterranean diet, according
to a new study.
Researchers tested the effects of eating a meal of olive oil and bread and
found people's blood vessels appeared healthier after eating olive oil rich in
Phenolics are plant-based compounds that are believed to have antioxidant,
anti-inflammatory, and anticlotting properties and are found in higher
concentrations in less processed oils.
Researchers say their results suggest virgin olive oil may be better for the
heart than seed oils because it is a natural juice that does not go through the
processing needed to extract oil from seeds, such as sunflowers and soybeans.
Therefore, the oil retains more of its original nutrients.
"It could be that the beneficial effect of the Mediterranean diet on
cardiovascular disease and arteriosclerosis depends on the synergistic effects
of the different nutrients that constitute complete foods and, as an example,
virgin olive oil is more than fat because it is a real juice with other healthy
micronutrients," says researcher Francisco Pérez Jiménez, MD, PhD, from the
Reina Sofia University Hospital in Córdoba, Spain, in a news release.
Phenolics Behind Olive Oil's Benefits
In the study, which appears in the Journal of the American College of
Cardiology, researchers compared the effects on blood vessel function of
eating virgin olive oil high in phenolics and olive oil that had been stripped
of most of its phenolics.
On different days, 21 otherwise healthy adults with high cholesterol ate a
breakfast of white bread and 40 milliliters (a little more than 2.5
tablespoons) of each of the olive oils. During the next four hours, researchers
took blood samples and monitored the participants' blood flow.
The results showed that the functioning of the inner lining of the small
blood vessels of the fingers of the participants and the concentration of
certain healthy components in the blood, such as nitric oxide, improved after
the breakfast of high-phenolic olive oil. But no such changes were found after
the low-phenolic meal.
Although more studies are needed to confirm these results, experts say the
findings suggest that even a very small change in diet, like using olive oil
rich in phenolic compounds, may have a significant effect in reducing the risk
of atherosclerosis (hardening of the arteries) and heart disease.
"This study demonstrates one possible mechanism by which olive oil rich
in phenolic substances improves the functioning of the circulation," says
Robert F. Wilson, MD, of the University of Minnesota in Minneapolis, in a news
release. "The authors found that after test subjects took olive oil spiked
with phenolic compounds, their blood vessels could dilate better, which could
improve blood flow. These findings are particularly interesting because similar
studies after high-fat meals, like a burger and fries, showed impairment of
normal blood vessel functions."