Health Benefits
Thanks to its status as a spotlight food in the Mediterranean Diet,
and thanks to extensive research on its unique phytonutrient
composition, olive oil has become a legendary culinary oil with very
difficult-to-match health benefits. Among its extensive list of
phytonutrients, no single category of nutrients is more important than
its polyphenols. The polyphenol content of this delicious oil is truly
amazing! The list below shows some of the key polyphenols found in olive
oil, organized by their chemical category:
- Simple Phenols
- Terpenes
- Flavones
- Hydroxycinnamic acids
- caffeic acid
- cinnamic acid
- ferulic acid
- coumaric acid
- Anthocyanidins
- Flavonols
- Flavonoid glycosides
- Lignans
- Hydroxybenzoic acids
- vanillic acid
- syringic acid
Most of the polyphenols in this list have been shown to function both
as antioxidants and also as anti-inflammatory nutrients in the body.
The very number and variety of polyphenols in olive oil helps explain
the unique health benefits of this culinary oil.
Anti-Inflammatory Benefits
It's unusual to think about a culinary oil as an anti-inflammatory
food. Plant oils are nearly 100% fat, and in a general dietary sense,
they are typically classified as "added fats." Intake of too much added
dietary fat can be a problem for many reasons—including reasons
involving unwanted inflammation. So it's pretty remarkable to find a
culinary oil that's repeatedly been shown to have anti-inflammatory
properties and provide health benefits in the area of unwanted
inflammation. Yet that's exactly the research track record that
describes extra virgin olive oil.
The anti-inflammatory strength of olive oil rests on its
polyphenols. These anti-inflammatory compounds include at least nine
different categories of polyphenols and more than two dozen
well-researched anti-inflammatory nutrients. Research has documented a
wide variety of anti-inflammatory mechanisms used by olive oil
polyphenols to lower our risk of inflammatory problems. These mechanisms
include decreased production of messaging molecules that would
otherwise increase inflammation (including TNF-alpha, interleukin
1-beta, thromboxane B2, and leukotriene B4); inhibition of
pro-inflammatory enzymes like cyclo-oxygenase 1 and cyclo-oxygenase 2;
and decreased synthesis of the enzyme inducible nitric oxide synthase.
In heart patients, olive oil and its polyphenols have also been
determined to lower blood levels of C-reactive protein (CRP), a widely
used blood measurement for assessing the likelihood of unwanted
inflammation. They have also been found to reduce activity in a
metabolic pathway called the arachidonic acid pathway, which is central
for mobilizing inflammatory processes.
These anti-inflammatory benefits of extra virgin olive oil do not
depend on large levels of intake. As little as 1-2 tablespoons of extra
virgin olive oil per day have been shown to be associated with
significant anti-inflammatory benefits.
Cardiovascular Benefits
Many different cardiovascular problems—including gradual blocking of
the arteries and blood vessels (called atherosclerosis)—have their
origin in two unwanted circumstances. The first of these circumstances
is called oxidative stress. Oxidative stress means too much damage (or
risk of damage) from the presence of overly reactive oxygen-containing
molecules. One of the best ways to help avoid oxidative stress is to
consume a diet that is rich in antioxidant nutrients. The second of
these circumstances is ongoing (chronic) and undesirable low-level
inflammation. Undesirable and chronic inflammation can result from a
variety of factors, including unbalanced metabolism, unbalanced
lifestyle, unwanted exposure to environmental contaminants, and other
factors. One of the best ways to help avoid chronic and unwanted
inflammation is to consume a diet that is rich in anti-inflammatory
nutrients. Any food that is rich in antioxidant and anti-inflammatory
nutrients is a natural candidate for lowering our risk of heart
problems, because it contains the exactly right combination of nutrients
to lower our risk of oxidative stress and chronic, unwanted
inflammation. Many foods contain valuable amounts of antioxidants and
anti-inflammatory compounds, but few foods are as rich in these
compounds as extra virgin olive oil, and this fact alone accounts for
many of the research-based benefits of this culinary oil for health of
our cardiovascular system.
In terms of antioxidant protection for our blood vessels, olive
oil has been shown to lower risk of lipid peroxidation (oxygen damage to
fat) in our bloodstream. Many of the fat-containing molecules in our
blood—including molecules like LDL—need to be protected from oxygen
damage. Oxygen damage to molecules like LDL significantly increases our
risk of numerous cardiovascular diseases, including atherosclerosis.
Protection of the LDL molecules in our blood from oxygen damage is a
major benefit provided by olive oil and its polyphenols. Equally
important is protection against oxygen damage to the cells that line our
blood vessels. Once again, it's the polyphenols in olive oil that have
been shown to provide us with that protection.
One process we don't want to see in our blood vessels is too much
clumping together of blood cells called platelets. While we want to see
blood platelets clump together under circumstances like an open wound,
where their clumping together acts to seal off the wound, we don't want
this process to occur in an ongoing way when there is no acute
emergency. Several of the polyphenols found in olive oil—including
hydroxytyrosol, oleuropein and luteolin—appear to be especially helpful
in keeping our blood platelets in check and avoiding problems of too
much clumping (called platelet aggregation). There are also two
messaging molecules (called plasminogen activator inhibitor-1 and factor
VII) that are capable of triggering too much clumping together of the
platelets, and the polyphenols in olive oil can help stop overproduction
of these molecules.
Olive oil is one of the few widely used culinary oils that
contains about 75% of its fat in the form of oleic acid (a
monounsaturated, omega-9 fatty acid). Research has long been clear about
the benefits of oleic acid for proper balance of total cholesterol, LDL
cholesterol, and HDL cholesterol in the body. When diets low in
monounsaturated are made high in monounsaturated fat (by replacing other
oils with olive oil), research study participants tend to experience a
significant decrease in their total blood cholesterol, LDL cholesterol,
and LDL:HDL ratio. Those are exactly the results we want for heart
health. In addition to these cholesterol-balancing effects of olive oil
and its high oleic acid content, however, comes a new twist: recent
research studies have shown that olive oil and its oleic acid may be
important factors for lowering blood pressure. Researchers believe that
the plentiful amount of oleic acid in olive oil gets absorbed into the
body, finds its way into cell membranes, changes signaling patterns at a
cell membrane level (specifically, altering G-protein associated
cascades) and thereby lowers blood pressure.
Interestingly, a recent laboratory animal study adds one note of
caution for anyone wanting to bring the unique cardiovascular benefits
of olive oil into their diet. This study found that cardiovascular
benefits from olive oil and its polyphenols were not realized when the
laboratory animals consumed too many calories and too much total food.
This result suggests that olive oil—outstanding as it is in polyphenol
protection of our cardiovascular system—needs to be integrated into an
overall healthy diet in order to provide its expected benefits.
Digestive Health Benefits
Benefits of olive oil for the digestive tract were first uncovered in
research on diet and cancers of the digestive tract. Numerous studies
found lower rates of digestive tract cancers—especially cancers of the
upper digestive tract, including the stomach and small intestine—in
populations that regularly consumed olive oil. Studies on the
Mediterranean Diet were an important part of this initial research on
olive oil and the digestive tract. Protection of the lower digestive
tract (for example, protection of the colon from colon cancer) is less
well-documented in the olive oil research, even though there is some
strongly supportive evidence from select laboratory animal studies. Many
of these anti-cancer effects in the digestive tract were believed to
depend on the polyphenols in olive oil and their antioxidant plus
anti-inflammatory properties. One particular category of polyphenols,
called secoiridoids, continues to be a focus in research on prevention
of digestive tract cancers.
Recent research has provided us with even more information,
however, about olive oil, its polyphenols, and protection of the
digestive tract. One fascinating area of recent research has involved
the polyphenols in olive oil and the balance of bacteria in our
digestive tract. Numerous polyphenols in olive oil have been shown to
slow the growth of unwanted bacteria, including bacteria commonly
responsible for digestive tract infections. These polyphenols include
oleuropein, hydroxytyrosol, and tyrosol. Some of these same
polyphenols—along with other olive oil polyphenols like ligstroside—are
specifically able to inhibit the growth of the
Helicobacter pylori bacterium. This effect of the olive oil polyphenols may be especially important, since overpopulation of
Helicobacter
bacteria coupled with over-attachment of Helicobacter to the stomach
lining can lead to stomach ulcer and other unwanted digestive problems.
Here the interesting part of Health Benefits:
Bone Health Benefits
Support of overall bone health is another promising area of olive oil
research. While most of the initial study in this area has been
conducted on laboratory animals, better blood levels of calcium have
been repeatedly associated with olive oil intake. In addition, at least
two polyphenols in olive oil—tyrosol and hydroxytyrosol—have been shown
to increase bone formation in rats. A recent group of researchers has
also suggested that olive oil may eventually prove to have special bone
benefits for post-menopausal women, since they found improved blood
markers of overall bone health in female rats who had been fed olive oil
after having their ovaries removed. Taken as a group, the above studies
suggest that bone health benefits may eventually be viewed as an
important aspect of olive oil intake.
Cognitive Benefits
Improved cognitive function—especially among older adults—is a
well-known feature of the Mediterranean Diet. As the staple oil in that
diet, olive oil has been of special interest for researchers interested
in diet and cognitive function. In France, a recent study large-scale
study on older adults has shown that visual memory and verbal fluency
can be improved with what the researchers called "intensive use" of
olive oil. In this case, "intensive use" meant regular use of olive oil
not just for cooking, or as an ingredient in sauces and dressings, but
in all of these circumstances.
Equally fascinating to us in the area of cognition has been
recent research on olive oil intake and brain function. In laboratory
animals with brain function that had been compromised by lack of oxygen,
consumption of olive oil helped offset many different types of
brain-related problems, including unbalanced water content, unbalanced
nervous system activity, and too easy passage of molecules across the
blood brain barrier. This animal research has given scientists many
further clues about the ways in which olive oil might provide us with
cognitive benefits. The ability to help protect our brain during times
of imbalance may turn out to be one of the special health benefits
offered by this unique culinary oil.
Anti-Cancer Benefits
The polyphenols found in olive oil are a natural for helping us lower
our risk of certain cancer types. Many types of cancer only get
initiated when cells are overwhelmed by oxidative stress (damage to cell
structure and function by overly reactive oxygen-containing molecules)
and by chronic excessive inflammation. Since the polyphenols in olive
oil act both as antioxidants and anti-inflammatory molecules, they are
perfectly suited for lowering our cells' risk of oxidative stress and
chronic unwanted inflammation. Research studies have shown that as
little as 1-2 tablespoons of olive oil per day can lower our risk of
certain cancer types, including cancers of the breast, respiratory
tract, upper digestive tract, and to a lesser extent, lower digestive
tract (colorectal cancers). In some research studies, the anti-cancer
benefits of olive oil do not show up until the diets of routine olive
oil users are compared with the diets of individuals who seldom use
olive oil and who instead consume added fats that are more saturated in
composition (for example, butter).
While most of the anti-cancer research on olive oil has focused
on its polyphenols and their antioxidant and anti-inflammatory
properties, several studies have uncovered other fascinating ways in
which olive oil provides its anti-cancer benefits. These other ways
include the improvement of cell membrane function in a way that lowers
risk of cancer development and the altering gene expression in cells in a
way that enhances their antioxidant defense system. A final important
mechanism linking olive oil intake to decreased cancer risk involves
protection of our DNA. The antioxidants in olive oil appear to have a
special ability to protect DNA (deoxyribonucleic acids)—the key chemical
component of genetic material in our cells—from oxygen damage. DNA
protection from unwanted oxidative stress means better cell function in
wide variety of ways and provides a cell with decreased risk of cancer
development.
There is also encouraging research on the potential for olive oil
to help with control of certain cancers once they have already
developed. For example, improvement of breast cancer status has been an
area of particular interest in olive oil research. Here some of the
research has focused on the secoiridoids in olive oil (especially
oleocanthal), and its ability to help keep breast cancer cells from
reproducing. Another example involves the ability of hydroxytyrosol (HT)
in olive oil to trigger programmed cell death (apoptosis) in colon
cancer cells. HT may be able to accomplish this anti-cancer effect by
helping block the enzymatic activity of fatty acid synthetase (FAS).
These cancer-controlling properties of olive oil and olive oil
constituents are generally referred to as the "antiproliferative"
properties of olive oil. We expect to see more future research in this
area.
