Trans fat is found in most margarines (especially stick margarines) and vegetable shortening, and in foods made with those products. It also can be found in most commercially fried foods and in processed foods because it increases a food product’s shelf life and stabilize flavor and texture. The US Food and Drug Administration (FDA) estimates that 40 percent of the trans fat we consume comes from baked goods such as cakes, cookies, crackers, pies and breads; 21 percent is from animal products and 17 percent is from margarine. The other 22 percent is divided among fried potatoes, snacks, shortening, salad dressing, cereal and candy.
An AGA member, director of nutrition, departments of gastroenterology and hepatology, Dartmouth-Hitchcock Medical Center, Lebanon, N.H., reveals that the consumption of foods containing trans fat has significantly increased in the past several years. He notes, that at the end of the 2oth century, there was a decrease in heart disease and a decrease in meat and dairy consumption. At the same time, food manufacturers shifted production to foods made with margarine, shortening and trans fatty acids made from hydrogenated oils. People have cut back on meat and dairy but are eating more trans fatty acids in packaged foods and in fast foods, most of which is fried in hydrogenated fats. Consumption of these foods has skyrocketed.
How much is too much? The FDA estimates that the average daily intake of trans fat by Americans 20 years of age and older is 5.8 grams, or 2.6 percent of calories, which experts believe to be a reasonable intake. Instead of assigning a maximum number of trans fat grams that can be consumed, the panel concluded that trans fat combined with saturated fat should be less than 10 percent of daily calorie intake. It is the sum of the two that is important to minimize rather than focusing on one of the other.
In July 2003, the FDA mandated that manufacturers list trans fat on the nutrition facts panel of all foods by January 1, 2006. Some manufacturers are already doing so. The FDA predicts that three years after the labeling requirements change, "trans fat labelings would annually prevent from 600 to 1,200 heart attacks and save 250 to 500 lives.
Doctors believe this label change is a good thing for consumers. Not only will consumer be better informed, it makes manufacturers more accountable and gives them an incentive for making modification to their products because they know the trans fat in their products. That was the case when, in 1993, the FDA required labels to list saturated fat. Unfortunately, manufacturers reduced saturated fat in many products by replacing it with trans fat. Under the new FDA labeling requirements, manufacturers can label products containing less than 0.5 grams of trans fat per serving as having 0 grams of trans fat. So, a product may contain shortening or partially hydrogenated vegetable oil, but its label will say it has 0 gram of trans fat. This is not as inconsequential as it sounds. For example, a label may say a serving of potato chips has 0 gram of trans fat, when it actually has 0.4 grams. If a serving is a handful, and you eat a lot of handfuls, which can add up pretty quickly. If hydrogenated or partially hydrogenated oils and shortening are listed on a food, don’t eat it. We suggest you choose another product if the terms appear near the top of the ingredients list, since ingredients are listed in order of descending weight in the product. Beware of parentheticals in which ingredients for part of the product are listed, such as enriched flour in a cracker; this makes ingredients high in trans fat appear further down the list than they actually are.
The big picture. Butter has far less trans fat than margarine, but cautious consumers must have tunnel vision when it comes to trans fat. Don’t forget about saturated fat, fiber and nutrients – there is a lot of things to take into account. It’s true that butter contains 0.3 grams of trans fat compared to 2.8 grams in stick margarine and 0.6 in tub margarine. However, the combined saturated and trans fat in one tablespoon of butter is 7.5 grams, 4.5 for stick margarine, and only 1.8 for tub margarine. The tub margarine seems to be the healthiest of the three choices. It may actually be better to eat butter than margarine. Even with what we know now, butter on a baked potato once a month is better than a tub of margarine once a month. You have to look at the whole day and your general pattern of eating. For example, if a person uses whole-milk dairy products but doesn’t eat meat or processed foods, trans fat is "probably not going to be a problem."
When watching out for trans fat, use common sense. Obviously whole-grain bread with a small amount of hydrogenated oil is better than white bread and is certainly better than a doughnut.