it comes to heart health, virgin olive oil may have an
edge over other vegetable fats, new research suggests.
Reporting 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 "non-virgin" variety. 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,
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 levels. The
men used the oils in place of other dietary fats.
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.