Just as we had all gotten used to being on the lookout for saturated fat (bad fat) in our favorite foods, yet another type of artery-clogging and heart-stopping fat is capturing the attention of doctors, dietitians and researchers: trans-fatty acids, or trans-fats.
A study recently published in The New England Journal of Medicine suggests that trans-fats may pose cardiac risks as bad as those of saturated fat. In the Journal of the American Heart Association, another study goes so far as to report that French fries cooked in saturated fat may be healthier for your heart than those most people eat today, which typically are cooked in hydrogenated vegetable oils. The same study reported that trans-fats may actually be worse for your heart than saturated fats, mostly because trans-fats seem to raise low-density lipoprotein (LDL or "bad cholesterol") and lower high density lipoprotein (HDL or "good cholesterol").
As if that wasn't enough, here's the really bad news: trans-fats can be found in most popular snack foods such as commercially baked cookies, cakes and crackers, French fries, chocolate bars, chips and microwave popcorn -- just to mention a few items. And they are also present in most types of tub and stick margarine and shortening made from vegetable oil.
But wait a minute -- aren't vegetable oils and vegetable oil-based spreads supposed to be good for you compared to butter? Well, not if you get a dose of hydrogenated oil with them.
"The food manufacturers love hydrogenated oils because they make their products all stable," says Patty Seebeck, a dietitian and nutrition services coordinator at the Heart Institute of Spokane. "But what may be good for them sometimes makes our arteries take a beating."
Hydrogenated oils are man-made, and from a manufacturer's standpoint they are a pretty clever invention. In the search for a substitute for butter -- which is solid at room temperature but has too high a saturated fat content for many consumers' diets -- food manufacturers came up with hydrogenated oils as a substitute fat that remains solid at room temperature (as opposed to oil), but without the dreaded saturated fat content.
"With the hydrogenated oils, what they have done is they have taken a healthy fat [vegetable oil] and changed it so it's more stable and holds up better to shelf life," says Seebeck. During the hydrogenation process, hydrogen atoms are added to the fatty acids, and that's what makes the oils solidify at room temperature. Some nutritionists also worry that oils such as palm and cottonseed oil never were meant to be part of a human diet, until they were first hydrogenated and turned into semi-solid fat products in the early-1940s. But it's the trans-fats that are causing the most worry right now.
"What's the problem with trans-fats is that when you eat them, they act as saturated fat because they have same characteristics -- they increase the risk of heart disease," says Seebeck.
In Europe, trans-fats have been under investigation through the joint European TRANSFAIR project, coordinated by the Netherlands Organization for Applied Scientific Research, since 1996. That study followed the consumption, use and cardiac consequences of trans-fats in 15 different countries and documented a clear link between trans-fats and heart disease. As Europeans are growing steadily more fond of fast food, that has lead to some countries calling for a severe reduction of trans-fats in the food source. In Denmark, the FDA's Danish equivalent just last week proposed to eliminate trans-fats from commercial foods by the year 2005.
Just a couple of years ago, butter was deemed the sure route to a heart attack in nutrition circles, but with this latest research into the trans-fatty acids contained in vegetable-based spreads such as margarine, butter is starting to look good again.
The thing is that a regular stick of margarine has about 2.4 grams of trans-fats (and 2.3 grams of saturated fat), while butter has only 0.3 grams of trans-fats (but 7.2 grams of saturated fat). But Seebeck cautions that a wish to avoid trans-fats is not a green light to indulge in butter instead.
"See? This is what I like about nutrition, it's not an exact science," she laughs. "You have to look at the big picture of what people eat. When I look at a heart patient, I ask how much butter they consume, and if it's only a teaspoon on the toast every morning, then I leave that alone -- but if they pile it on everything, then I suggest an alternative."
And of the alternatives, Seebeck says the closer you get to a type of fat that's liquid at room temperature, the better.
"Obviously olive oil isn't going to work for everything, but squeezeable margarine is better than the soft tub margarine and so on," she says. "In Europe, they have figured out how to make margarine without the trans-fats, it's of course more expensive." Some types of trans-fat free margarine are already available in the U.S.
"I always tell my clients they should be careful with margarine. Get one that lists a liquid vegetable oil or water as first ingredient," says Seebeck. "Some of them come right out and say partially hydrogenated oil as the first ingredient -- if that's the case, don't eat it."
As a matter of fact, she adds, don't eat anything that has a hydrogenated oil as one of the first three ingredients, since ingredients on the labels are organized in descending order. She also advises people to stay away from commercially baked products, crackers , cookies, box cakes, chocolate bars and TV dinners.
As for the higher prices of fresh and less processed foods, she's got this to say: "You have to look at the long-term perspective. When my clients complain it's expensive to live healthy, I always say, 'Well, triple-bypass surgery is expensive, too.' "