Trans Fat


How Trans Fats Trick Your Genes
You may have heard that trans-fatty acids are as bad as, if not worse than, saturated fat, posing a threat to heart health that has prompted the Food and Drug Administration to require disclosure of the dangerous lipid on products' ingredient lists and Nutrition Facts panels, a move that has made many a food manufacturer scrambling to reconstitute their recipes.
The health threat is real -- and those of you who have diligently gone through your pantry to eliminate products containing TFAs listed by their various sobriquets ("partially hydrogenated oils," "hydrogenated vegetable oils," "shortening," etc.) have done your bodies a good deed.

Why They're Bad
According to the American Heart Association, not only do TFAs raise levels of LDL ("bad") cholesterol, they also lower HDL ("good") cholesterol. Their effects are so pernicious that replacing just 2% of calories from TFAs with calories from unsaturated fats was associated with an astonishing 53% lower risk of coronary heart disease, according to Harvard's ongoing Nurses' Health Study.
The elevation of cholesterol -- in addition to evidence showing TFAs might increase insulin resistance (and thus raise the risk of developing type 2 diabetes) -- has led many medical experts to suggest that TFAs may have even stronger adverse effects than those of saturated fats. But what's remained somewhat murky till now is an understanding of the precise mechanism by which TFAs send blood levels of cholesterol and triglycerides soaring.

New: How TFAs Work
Scientists at Harvard's Dana-Farber Cancer Institute have identified a molecular mechanism in the liver that finally explains how trans fats play their genetic tricks. According to landmark research published in the Jan. 28 issue of Cell, trans fat consumption triggers a biochemical switch in the liver that "turns on" the genes that push cholesterol production into overdrive. Put another way: When TFAs arrive at the liver, they prompt interaction between certain proteins, which activate the genes that direct the liver to manufacture more cholesterol, which it does in the form of VLDL cholesterol -- the very worst kind.
Says Harvard researcher Bruce Spiegelman: "What we have found is a missing link, a mechanism by which saturated fats and trans fats can do their dirty work." Unsaturated fats do not activate the same gene activity to the same degree, which is why they do not raise cholesterol as do saturated and trans-fats.
About one in five Americans has high blood cholesterol (>240 mg/dL), according to the American Heart Association, putting them at twice the risk of heart attack as people whose cholesterol level is under 200. Reducing your cholesterol by a mere 10% at age 40 can lower your risk of a heart attack by 50%, by 40% at age 50, by 30% at age 60, and by 20% at age 70.
Since saturated fat and TFAs are the main dietary cause of high blood cholesterol, try to limit consumption or substitute polyunsaturated and monounsaturated fats wherever possible. Saturated fats derive mainly from animal sources, such as meat, cheese and other whole milk dairy products.
Trans fats are primarily produced through hydrogenation -- a process that turns liquid vegetable oils into solids, such as the shortening and margarine often used in baked goods and snack foods. Fried food and fast food, in general, tend to be high in TFAs. Below, we provide a list of some seemingly "healthy" foods where trans-fats can secretly lurk (though more and more manufacturers are coming up with alternate formulations). So always check the labels -- and chuck the TFAs.
Microwave popcorn
Granola cereal & bars
Non-dairy creamer
Dried soup mix