are Trans Fats?
may have first become aware of trans fats in the mid-1990s,
when reports began to surface that margarine, often touted as
healthy, contains these sinister fats and may not be preferable
to butter after all. It turned out that trans fats were in most
processed foods in the supermarket and in many fast foods. In
1994 Harvard researchers went so far as to conclude that trans
fats were responsible for more than 30,000 of the countrys
annual deaths from heart disease. Other scientists dismissed
these fears as overblown, and since then the debate has continued.
Heres the latest.
are trans fats and why are they added to foods?
partially hydrogenatethat is, add hydrogen tocorn,
soybean, and other highly unsaturated oils to make them more
solid and stable. The result: some of the polyunsaturated and
monounsaturated fatty acids in the oils become more saturated.
This process also transforms the chemical structure of some
unsaturated fatty acids in other subtle ways, producing trans
fatty acids (or simply trans fats). Hydrogenation gives margarines,
shortening, and puddings a creamy consistency, and prolongs
the shelf life of crackers, cakes, cookies, chips, popcorn,
chocolate candy, and other foods that contain the semi-solid
oils. Because they are less likely to turn rancid, hydrogenated
oils are also often used for deep-frying in fast-food restaurants.
are trans fats bad?
regular unsaturated fats lower blood cholesterol, trans fats
act more like saturated fatsraising total and LDL ("bad")
cholesterol. In addition, in a sort of double whammy, trans
fats lower protective HDL ("good") cholesterol, which
makes them, overall, even worse than saturated fats. They may
also increase the risk of heart disease in other ways: for instance,
they boost blood triglyceride levels and seem to impair the
ability of blood vessels to dilate. They have also been linked
to an increased risk of diabetes.
1993 study of nearly 90,000 women found that those who ate the
most foods high in trans fats (especially margarine) had a more
than 50% higher risk of heart disease than women who rarely
ate these fats. Two recent Dutch studies also found increased
coronary risk among people consuming high levels of trans fats.
How much trans fats do we eat?
are that trans fats provide 2 to 4% of our total daily calories,
but other estimates are higher. The fact is, no one really knows.
Moreover, any such average means little, since some of us consume
little or no trans fats, while others consume two or three times
the average. A large order of fast-food fries, for instance,
or a frosted donut by itself can put you over the average. In
addition, food manufacturers often change the types of oils
they use and the degree of hydrogenation of the oils, so its
impossible to keep track. And food labels dont help (see
researchers believe that since trans fats make up only a small
portion of our fat intake, worries about them are exaggerated.
It is true, however, that during the past 15 years weve
been consuming more and more trans fats, since food makers have
been using more hydrogenated oils.
there any way to tell from the label how much trans fat is in
If you see partially hydrogenated oil on the ingredients list,
you know the food contains some trans fats. But nutrition labels
dont specify how much. This may actually encourage manufacturers
to use hydrogenated oils, since unlike the saturated fats they
often replace, the trans fats remain invisible on nutrition
labels. And trans fats are not currently counted as saturated
fat on labels.
years ago the FDA proposed adding the trans fats content to
nutrition labels, but the process has been put on a back burner.
As things stand, foods that contain trans fats are even allowed
to make heart-healthy claims. For instance, Triscuit crackers
are high in trans fats, yet the box boasts "no cholesterol"
and "low saturated fat." Labeling
of trans fats is long overdue.
things are clear
You neednt worry about occasionally eating small amounts
of margarine (or, for that matter, butter, which is rich in
saturated fat but contains no trans fats). However, if you
eat lots of margarine, try to use less, or switch to a more
healthful type. The more solid the vegetable oil, as in stick
margarine, the more hydrogenated it is, and therefore the
more artery-damaging trans fats it has. Tub margarines are
soft and contain lots of unaltered polyunsaturated fats, which
actually help lower blood cholesterol. "Diet" margarines
are softest and have more waterand less than half the
fat of other margarines. Liquid "squeeze" margarines
are also good alternatives.
Even if you dont eat margarine, you may be consuming
lots of trans fats. Processed and fast foods that contain
partially hydrogenated oils supply more than two-thirds of
the trans fats in the American diet. If you eat these foods
often, cut back. Trans fats are only one of the nutritional
strikes against them.
developments: Food makers, especially in Europe, have
been finding new ways to reduce trans fats in foods. In this
country, margarine makers have been reformulating many products
to cut down on trans fat (and total fat). And the USDA has developed
a new process called low-trans hydrogenation, which produces
fewer trans fats and may soon be used for margarines and other
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