This week, we're taking a closer look at olive oil. By now, the average
educated adult knows that for healthy eating, lard is a bad fat,
cottonseed oil not much better, and olive oil is just dandy as long as
it isn't heated too much. Now a new study published in Neurology
-- which will probably come as a huge surprise to Dr. Dean Ornish--shows
that people who use lots of olive oil, even in cooking, have a
considerably lower stroke risk than people who don't use it at all. The
French study of 7,625 people aged 65 found a 41 percent reduced stroke
risk in heavy olive oil users. In fact, the participants were divided
into three groups and those with the highest olive oil intake had a
whopping 73 percent reduced stroke risk compared to the group with the
lowest olive oil intake. The effect remained consistent even after
controlling for other factors such as overall diet and health
conditions, showing that olive oil confers benefits even independent of
the Mediterranean Diet of which it is a cornerstone. Prior to this
study, research had indicated that high olive oil consumption reduced
heart attack risk, but this new research points to the fact that its
benefits extend to other areas of health, and in a big way.
Before you rush to Costco for a giant tub of olive oil to
guzzle, consider that the researchers caution that the results might
actually indicate something other than the miraculous properties of
olive oil. For instance, they say, olive oil consumers might be
healthier, wealthier, and happier than those who rely on Safflower. On
the other hand, as already indicated, the study did control for those
factors, so olive oil emerges looking like a big winner. The key here is
that you need to use only organic, extra-virgin, cold first-pressed,
which is rich in phytonutrients. Studies show that in comparison to the
pure stuff, processed olive oils don't necessarily offer any benefit at
all. Although the report on the French study didn't mention what type of
olive oil was tested, in France, virtually all the available olive oil
is cold-pressed extra virgin.
Why is olive oil such a healthy fat compared to the typical
fat added to commercial goods? First, olive oil contains a high
proportion of antioxidants, particularly polyphenols, which have
powerful anti-inflammatory properties.3 Studies have shown that one of
the polyphenols, hydroxytyrosol (HT), has a particularly powerful
ability to protect blood vessel walls. Also, the composition of olive
oil differs from most commercial cooking oils in that about 75 percent
of the fat comes in the form of oleic acid, which is a monounsaturated,
omega-9 fatty acid -- and that's a good thing. Other oils with lower
monounsaturated content are higher in omega-6 fatty acids, and high
consumption of omega-6 fatty acids causes a build-up of harmful
"non-esterified fatty acids," otherwise known as a NEFAs. NEFAs in the
blood are associated with sudden heart attacks. Compare olive oil to
soybean oil, which is only 50-55 percent monounsaturated, or safflower
oil, which is only 15 percent.
The positive health benefits of the high proportion of
monounsaturated fatty acids (MUFAs) in olive oil include reduction of
overall cholesterol levels as well as of LDL cholesterol, and
improvement in LDL to HDL ratios. Plus, the high ratio of MUFAS helps to
regulate blood glucose levels and apparently, to lower blood pressure.4
Which brings us to the problem of cooking at high heats and the
puzzling results of the French study. The thing is that any oil that is
heated beyond the point at which it smokes can release carcinogenic free
radicals, and most commercial varieties of olive oil have a low smoke
point. In other words, it's generally not considered a great choice for
cooking at high heats, since the negative impact of creating free
radicals in heating cancels out the positive benefits the oil proffers.
On the other hand, those who cooked with olive oil in the
French study clearly benefited. The reason might have to do with the
quality of the oil they used. Although different charts list different
values for the same oils (since smoke points are not absolutes), some
experts contend that refined olive oil has a smoke point of around 350
degrees, while high-quality (low acidity, less than .8 percent)
extra-virgin has a much higher smoke point, up around 410 degrees.
"Virgin" olive oil is not blended with other oils, but has a higher
acidity, less quality. "Light" olive oil has a higher smoke point, but
it is made from refined olive oil, which means it is a refined blend of
pomace oil and virgin olive oil. Lastly, pure "olive oil" is really
just a blend that contains as little as 5 to 10 percent virgin olive oil
and is cheaper to produce. In any event, extra virgin olive oil
maintains its nutritional integrity even when heated to high
temperatures, and even as it creates those carcinogens.
To be on the safe side, use olive oil only for
lower-temperature cooking. If you throw in with the olive oil lobby and
buy that the higher-quality product has a relatively high smoke point,
simply heat your oil in a pan and notice when it starts to emit smoke.
Voila! You've found the smoke point, and you need to draw the line
before that. As I've said before, you can use avocado oil for high
temperature cooking. Avocado oil has a very high smoke point by
comparison to other cooking oils. It will not burn or smoke until it
reaches 520 F (271 C), which is ideal for searing meats and frying in a
Wok. Other good choices include grapeseed oil (485 F) or rice bran oil
495 F. Again, look for organic, cold-processed oil. One other
possibility is Spectrum Naturals High Heat Canola oil, which can handle
temperatures up to about 450 degrees F.
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