Fat,
Good And Bad Fatty Acids
Fat
has been looked at with caution, and it has often been perceived as the villain.
There has been a perception, that fat is the "bad guy", the enemy that
is responsible for obesity, heart disease, clogged arteries and other ailments.
A lot of products line the supermarket shelves and proclaim that they are "no-fat"
or "low-fat" or "cholesterol-free".First of all it
is necessary to realize that there are fats that are essential and vital
for us. As mentioned before, our bodies need to have essential fatty
acids, as it cannot make them out of other nutrients. There are
fats, which are beneficial, and a small amount in our food plays a role to slow
down the entry of carbohydrates into the bloodstream. It also sends hormonal
signals to the brain: we feel satiated and no longer hungry. As a sensible rule
of thumb we should not exceed 30% of our caloric intake from fat! A group
of "good" fats are called monounsaturated fats. They occur
in olives or in olive oil, avocados, almonds and macadamia nuts. Next there
is the group of the poyunsaturated fats, which are divided into two groups: 1.
Those containing omega-3 fatty acids, a "good fat" source occuring
in foods like salmon, mackerel, sardines, tuna or fish oil. 2. Then there
is the sub-group containing omega-6 fatty acids, occurring
in corn oil, sesame oil, and grapeseed oil. They need to be balanced by omega-3-fatty
acids or they could lead to inflammatory conditions like arthritis (Ref.7,262). It
is the saturated fats, that are the "bad" fats. They occur
in animal fats like butter, lard, and dairy fat, but they are also found in tropical
oils (palm oil or coconut oil). The follwoing table was summarized by me from
data of Ref. 3, p. 108-109).
| Fat, the good, the
bad and the ugly | | Type
of fat: | Comments: |
| "good": | fats
and omega-3-fatty acids | good because they
are the only essential fatty acid that the body cannot make: found in salmon,
mackerel, sardines, tuna or fish oil. | | monounsaturated
fatty acids | good, because
not prone to oxidizing and no effect on insulin: found in olives, olive oil, avocados,
almonds and macadamia nuts | | "neutral": | omega-6-fatty
acids | only neutral, if balanced with omega-3-fatty
acids: corn oil,sesame oil, and grapeseed oil |
| "bad": | saturated
fats | raises LDL (=bad) cholesterol, found
in animal fats like butter, lard, dairy fat, but also found in tropical oils (palm
oil and coconut oil) | | "the
ugly": | hydrogenated fat or partially
hydrogenated fat, trans fatty acids, "pure vegetable shortening" | good
for long shelf-life of cookies, bad for your heart. Increases LDL and lowers HDL
cholesterol. Found in margarine, deep fried foods, lard, vegetable shortening |
Unfortunately there is another group that is the worst of
them all, those fats which contain trans fatty acids. They are called
trans fats and are like the new bad kid on the block: before the 20 th century
they did not exist. They were developed in an effort to transform liquid
oils into a spreadable fat. This way margarine was created. Also, the shelf life
of products containing trans fats is longer. This way, butter, which is an animal
fat that forms the bad cholesterol, plugs up arteries , and leads to heart attacks
and strokes was replaced. It certainly was cheaper than the expensive butter,also
it did not turn rancid like butter, but the trans fats in the margarine are even
worse than the fat in butter.Trans fats raise the bad cholesterol and at the same
time lower the good cholesterol, which is a double whammy to wreak havoc with
our health! Despite all the claims that some margarines are lower in trans
fat than others and are labelled "heart healthy", be aware that trans
fats at this point don't have to be listed on food labels. If you read the word
"hydrogenated",
it means "bad trans fats"!Foods
with high trans fat levels are best avoided altogether: deep fried foods like
french fries, chips or nachos are on this list. Cookies, pies and snack foods
are also on the "not wanted" list. A wide range of commercial bakery
products are prepared with shortening. The harmless sounding term "pure
vegetable shortening" is a trans fat and not harmless at all!
| The
do's and don'ts about fat intake | To
make sensible and healthy choices you do not need a degree in nutrition. All you
have to do is: 1. Read the labels and ingredient
lists. 2. Avoid products, which contain hydrogenated
or partially hydrogenated fats. 3. Eat one food
per day, which contains omega-3 fats.(If you do not like fish, take two capsules
of fish oil.) 4. Use some monounsaturated fats
like olive oil. 5. Do not exceed the 30% mark
of fat in your daily caloric consumption. With
these simple guidelines, fat will be your nutritional ally and not an enemy. |
See also this issue of a health newsletter in Jan. 2004: http://www.askdrray.com/previous2004healthnewsletterissues.html#oldfashionedfishoilboostshearthealth |
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