Trans Fats: The Science and the Risks
This man-made fat was developed to protect us against butter. Turns out, it acts like butter inside our bodies.
What Do Trans Fats Do Inside the Body? continued...
"The science that shows that trans fats
increase LDL cholesterol levels is outstanding and very strong. All evidence is
pointing in the same direction," Lichtenstein tells WebMD.
In the Nurse's Health Study, women who
consumed the greatest amount of trans fats in their diet had a 50% higher risk
of heart attack compared to women who consumed the least.
Some researchers suspect that trans fats
also increase blood levels of two other artery-clogging compounds -- a
fat-protein particle called lipoprotein(a) and blood fats called
Equally worrisome, population studies
indicate that trans fats may raise the risk of diabetes. Researchers at the
Harvard School of Public Health in Boston suggest that replacing trans fats in
the diet with polyunsaturated fats (such as vegetable oils, salmon, etc.) can
reduce diabetes risk by as much as 40%.
How much trans fat is safe? No one really
knows. Kava says the prestigious Institute of Medicine reported that there
isn't enough research yet to recommend a safe amount of trans fats. "We
know that like saturated fats, trans fats can raise bad cholesterol, but there
is conflicting data about what it does to good cholesterol," she says.
"I wish the data were stronger."
The FDA, while requiring manufacturers to
put the amount of trans fats on nutrition labels, will not require a percent
daily value (DV) for trans fat because there is not enough information at this
time to establish a such a value, she says. Food labels do offer such
information about saturated fats.
How Do Trans Fats Compare to Saturated Fats?
"Trans fats raise (bad) LDL cholesterol
levels slightly less than do saturated fats," says Lichtenstein. "But
saturated fats also raise levels of high density lipoprotein (HDL) or
"good" cholesterol, and trans fatty acids don't." Trans fats may
actually lower HDL. Thus, some researchers say trans fats are worse.
Lichtenstein, however, figures the two fats probably cause equal harm in our
diets because we eat far more saturated fat than trans fats.
The FDA estimates that Americans adults eat
5.8 grams of trans fats per day -- that's about 2.6% of our daily calories. By
comparison, we eat four to five times more saturated fat per day. About 40% of
our trans fat intake comes from cakes, cookies, crackers, pies, and bread,
while 17% comes from margarine.
Who Should Be Concerned About Trans Fats?
Of course, everyone should try to limit
their consumption of trans fats and saturated fats. However, "individuals
who are told by their physicians that they have elevated LDL cholesterol should
be most concerned," Lichtenstein says. "They should minimize their
intake of both trans fats and saturated fats."
Kava adds: "The most important thing is
looking at the number of calories and then serving size. Then check out
saturated fat and trans fat on the label. It might help some people make