Be A Trans-Fat Detective

Get to the bottom of how much of the hidden, harmful fats lurk in your food

By Elaine Magee, MPH, RD
WebMD Weight Loss Clinic - Expert Column

When you think of the "bad fats" -- the ones that can hurt your health -- you probably think of the saturated variety. They are the ones that can raise your levels of bad cholesterol, or LDL, as well as your risks of developing serious conditions like heart disease.

Well, you should know that saturated fats have some company in this department: the trans fats.

The Bigger Bad Boy

Health-wise, trans fats strike with a double whammy. They too can raise your levels of bad cholesterol, but they also can decrease your HDL, or "good" cholesterol. Together, these two effects are primary risks of developing heart disease, and they are a reason why many experts consider trans fats a bigger bad boy than saturated fat.

What are you supposed to do? For starters, lower the amounts of saturated and trans fats in your daily diet. You can do it by choosing reduced-fat foods, like lower-fat dairy and leaner cuts of beef. (They contain less total fat, less saturated fat, and less trans fats.) Reduced-fat crackers and microwave popping corn will contain less total fat, less saturated fat, and less trans fat. You get the picture.

And, it may not be a popular notion, but making your own meals -- yes, homemade ones -- really help you control how much fat you eat. You get to choose the type and amount of fat in each recipe you prepare. If you make pie crust, biscuits, or waffles, use canola oil instead of shortening and use less cooking fat, in general, whenever possible. It's those smart substitutions that help a lot.

Where Trans Fats Lurk

I keep mentioning all these terms like unsaturated, saturated, and trans fats. When you think about types of fats, remember that a lot has to do with the amount of hydrogen in each type of fat molecule.

When the molecules are all full of hydrogen -- or are saturated with it, the fat tends to be solid at room temperature. The monounsaturated fats have one double bond in their carbon chain and polyunsaturated fats have more than one double bond, and both are better for your health than saturated fats and trans fats.

But trans fats make things a bit more complicated. They get their name from their distinct chemical structure. They occur naturally in small amounts in meat and dairy products. But they can be found in higher quantities in partially hydrogenated vegetable oils which are primarily used in shortening, some margarines and processed foods .

Remember about that hydrogen. When food manufacturers need a more stable, solid form of oil to make their products, they'll bubble hydrogen gas through vegetable oil. The process actually changes the chemical structure of the fat, turning some of it into trans fats. The oil doesn't take up all the hydrogen to become fully saturated, yet it does become a harmful type of fat.

Trans fats are lurking in all commercially made food products containing partially hydrogenated oils or shortening. They are also hiding in frying fats used by many fast food joints. (A 1998 Dutch study estimated that in the frying fat fast food chains use, a third of it is made up of trans fats.)

These common foods most likely contain trans fats:

  • Most margarines and shortenings;
  • Frying fats in processed foods;
  • Deep-fried fast food, like french fries;
  • And any of food that list "partially hydrogenated oils" in the ingredients, such as: crackers, cake mixes, snack cakes, snack foods, chips, doughnuts, pie crusts, biscuits, breakfast cereals, frozen waffles, microwave popcorn, packaged cookies, and other baked and fried items.

The Daily Dose of Trans Fats

How much trans fats do Americans eat on a daily basis? Good question. It's almost impossible to answer accurately because manufacturers are not yet required to list amounts of trans fats on food labels. And when a product does use the harmful fat, there's no standard amount of how much is in there.

Use The Clues

Until labels give us trans fat information, be sure to check the ingredient list for the words "partially hydrogenated oil" or "shortening." If they are in the first three ingredients for a particular food product, and the food product contains quite a bit of total fat, chances are there is a fair amount of trans fats in that food.

Pay special attention to margarines that list the grams of monounsaturated fat and polyunsaturated fat along with the total grams of fat and grams of saturated fat. With this info, you can actually figure out the grams of trans fatty acids by doing a little math:

  • Step 1 -- Add up the grams of saturated fat, monounsaturated fat, and polyunsaturated fat.
  • Step 2 -- If the number from step 1 is less than the total amount of fat on the label, you can assume the missing grams are trans fats.

"It may not be a popular notion, but making your own meals -- yes, homemade ones -- really help you control how much fat you eat."

More Reasons to Avoid Trans Fats

Trans fats may increase the risk of type 2 diabetes in women. In a 2001 study, researchers found that when women replaced 2% of the trans fats they ate with polyunsaturated fat, they dropped their risk of diabetes by 40%.

But for women, the risks don't end there. Trans fats may increase their risk of colon cancer, too. Researchers suspect that trans fatty acids are carcinogenic, but they need more proof to be sure. They do know from a recent study that high levels of dietary trans fats doubled the risk of colon cancer in menopausal women not on hormone replacement therapy.

Trans fats also have been implicated in developing breast cancer. A Dutch study suggests an association between the amount of trans fat stored in the body and the risks of the disease in women after menopause.

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