|
McDonald’s, which is
rolling out its new printed nutrition
information on most of its packaging,
has stumbled upon a little problem. It turns
out that it underestimated the trans fat
content of its French fries by as much as
one-third. A large serving of French fries
contains a whopping 8g of trans fats, not
the 6g it previously listed on its
brochures, posters and on its web
site.
McDonald’s has been at the center of a
trans fat controversy once before. In 2004, BanTransFats,
which aims to reduce or eliminate trans fats
from foods, sued McDonald’s for failing to
make good on a promise to cut trans fats in
its products. The suit was settled, with
McDonald’s paying $7m to the American
Heart Association and $1.5m on informing
consumers about its failure to make the
change.
What are
trans fatty acids, and where do they come
from?
We're
used to hearing about saturated and
unsaturated fatty acids. Saturated fatty
acids - which come from animal fats (meat,
lard, dairy products) as well as tropical
oils such as coconut and palm oils - raise
the levels of LDL cholesterol. Unsaturated
fats - which come from vegetable oils - in
general, do not increase cholesterol levels,
and may reduce them.
Because
saturated fatty acids were found to be bad
for you a couple decades ago, the food
industry wanted to switch to using
unsaturated fatty acids. Unfortunately,
unsaturated fatty acids become rancid
relatively quickly. To combat the
instability of unsaturated fatty acids,
manufacturers began to
"hydrogenate" them, a process that
makes them more stable. The result was a
more solid and longer lasting form of
vegetable oil, called "partially
hydrogenated" oil.
Unfortunately,
when unsaturated vegetable fats are
subjected to the process of hydrogenation, a
new type of fatty acid is formed. This new
type of fatty acid is called trans fatty
acid. So when manufacturers began
substituting partially hydrogenated
vegetable oils for saturated fats in
processed foods, they began adding - for the
first time - relatively large amounts of
trans fatty acids to the typical diet.
So what's
the problem with trans fatty acids?
Trans
fatty acids turn out to increase total
cholesterol levels and LDL cholesterol
levels, and to reduce HDL cholesterol
levels. In other words, trans fatty acids
are detrimental to cardiac health.
Which is
worse - saturated fatty acids or trans
unsaturated fatty acids?
Both
saturated fats and trans fatty acids are bad
for you. Saturated fats are almost always
found in foods that also contain
cholesterol, so saturated fats offer a
"one-two" punch to heart health.
On the other hand, trans fatty acids not
only increase LDL cholesterol, they also
decrease HDL cholesterol. So while nobody
can say yet definitively which is worse, it
does appear that both are bad.
Which
foods contain trans fatty acids?
Fortunately,
it is relatively easy to identify foods that
contain relatively large amounts of trans
fatty acids: margarines (the more solid the
margarine, the more the trans fatty acids;
stick margarines contain the most, tub
margarines contain less, and semi-liquid
margarines contain the least;) high-fat
baked goods (especially doughnuts, cookies
and cakes;) and any product for which the
label says "partially hydrogenated
vegetable oils" (which, it sadly
appears, includes virtually all processed
foods.) DrRich is particularly distressed to
point out that trans fatty acids absolutely
lace his two favorite food groups: french
fries and potato chips. (This tragic warning
also includes corn chips and many crackers.)
Five small
chicken nuggets from a fast food chicken
outlet contained nearly 4 grams of trans
fat.
• Two
vegetable spring rolls from a Chinese
takeout contained about 1.7 grams of trans
fat.
• Even in
pizza, which many might consider one of the
healthier fast foods, you'd most likely
ingest about 1 gram of trans fat in two
slices -- most of it from vegetable
shortening used to process the crust.
|
