in the Annals of Internal Medicine, European researchers
say virgin olive oil may be particularly effective at
lowering heart disease risk because of its high level
of antioxidant plant compounds. In a study of 200 healthy
men, the researchers found that virgin olive oil --
rich in antioxidants called polyphenols -- showed stronger
heart-health effects than the more extensively processed
The findings suggest that virgin olive
oil has more going for it than its supply of heart-healthy
monounsaturated fat, according to the study authors.
Polyphenols, they say, may account for some of the health
benefits that have been attributed to the oil.
In fact, virgin olive oil is the only
vegetable oil that's rich in polyphenols, Dr. Maria-Isabel
Covas, the study's lead researcher, told Reuters Health.
"All vegetable oils other than
virgin olive oil are submitted to a (refining) process
in which polyphenols are practically lost," explained
Covas, a researcher at the Municipal Institute for Medical
Research in Barcelona, Spain.
Even "ordinary" olive oil
has a lower polyphenol content, she noted, because it's
a mixture of virgin olive oil and a more-processed form
of the oil.
For their study, Covas and her colleagues
had 200 young and middle-aged men use each of three
olive oils for three weeks apiece. One oil was a virgin
olive oil high in polyphenols; the other two were more
heavily processed varieties with moderate to low polyphenol
The men used the oils in place of other
At the end of the study, the researchers
found that the men's levels of "good" HDL
cholesterol were highest after their three weeks on
virgin olive oil. They also showed a greater decline
in markers of so-called oxidative stress -- a process
that helps deposit particles of "bad" LDL
cholesterol on the artery walls and can lead to a hardening
and narrowing of the vessels supplying the heart.
Monounsaturated fat is well known to
be a healthier alternative to the saturated fat found
in animal products like butter, Covas noted. That fact,
along with the benefits of polyphenols, she said, make
olive oil "a good source of fat."
But she stopped short of recommending
virgin olive oil as a replacement for other vegetable
oils, saying large clinical trials are needed to see
whether there's a health advantage.
SOURCE: Annals of Internal Medicine,
September 5, 2006.