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.
Where Did Trans Fats Come From?
Trans fats were developed during the
backlash against saturated fat -- the artery-clogging animal fats found in
butter, cream, and meats. Then food manufacturers realized that trans fats
lasted longer than butter without going rancid. The result: Today trans fats
are found in 40% of the products on your supermarket shelves.
"We used to use animal fats, and people
said, 'saturated fats are bad,' so we switched to trans fats," says Ruth
Kava, PhD, RD, director of nutrition at the New York City-based American
Council on Science and Health. "This kind of gives us an unfortunate focus
on ingredients rather than the whole diet when the problem isn't this fat or
that fat, it's too many calories."
"Anything was good if it decreased
saturated fat consumption in the 1950s through the 1980s," agrees Alice H.
Lichtenstein, Dsc, professor of nutrition at Tufts University in Boston.
"But then studies began to question trans fats," too. Finally, in the
1990s, the evidence became clear: When vegetable oil is turned into a solid,
like butter, it acts like butter inside the body.
Next, learn about the risks.
What Do Trans Fats Do Inside the Body?
Like saturated or animal fats, trans fats
contribute to clogged arteries. Clogged arteries are a sign of heart disease;
they increase your risk of both heart attack and stroke. Here's how it works:
Trans fats raise low-density lipoprotein (LDL) or "bad" cholesterol
levels. This contributes to the buildup of fatty plaque in arteries.
"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%.