MYTH: Saturated fats are worse than trans fats.
FACT: Both trans fats and saturated fats increase low-density lipoprotein (LDL) levels. But because trans fats also may decrease high-density lipoprotein, or "good cholesterol," levels, they're considered somewhat worse than saturated fats. Encourage patients to reduce both types of fats in their diet. The American Heart Association (AHA) recommends limiting saturated fats to less than 7% of total daily calories and trans fats to less than 1% of total daily calories.
MYTH: Trans fats can be completely eliminated from the diet.
FACT: Because small amounts of trans fats occur naturally in some meats and dairy products, you can't eliminate them from the diet. But you can reduce the amount of trans fats you consume. Avoiding foods that contain or are prepared with partially hydrogenated vegetable oils is the easiest way to minimize your intake of trans fats.
MYTH: Trans fats can be formed at home by cooking an oil to its smoking point.
FACT: Trans fats can't be produced during home cooking, even if the oil temperature is high enough to make oil smoke. This type of fat is produced when hydrogen is added to turn liquid vegetable oils into solid fats. However, letting oil reach the smoking point isn't good because it breaks down fatty acids, forming harmful oxidation products. Overcooked oil also makes fried foods taste bad.
MYTH: Because trans fats are created by hydrogenation, fully hydrogenated oils contain more trans fat than partially hydrogenated oils.
FACT: When liquid vegetable oil is fully hydrogenated, the amount of saturated fat increases, and almost no trans fats remain. Partially hydrogenated oils, however, do contain trans fats and are considered more harmful than fully hydrogenated oils.
MYTH: Naturally occurring trans fats are as harmful as other trans fats.
FACT: Some of the trans fats that occur naturally in beef, lamb, and full-fat dairy products are just as harmful as man-made trans fats. Because beef, lamb, and full-fat dairy products are high in saturated fats, the AHA recommends minimizing their consumption.
MYTH: Stearic acid, a type of saturated fat, increases LDL cholesterol levels.
FACT: Although it's a saturated fat, stearic acid appears to have little effect on cholesterol levels. Stable in storage and during frying, stearic acid is used in margarine, shortening, and spreads and as a cream base for baked goods.
MYTH: Interesterified fats, which have been chemically altered to change their texture or nutritional value, have been proven to be as dangerous as trans fats.
FACT: The health effects of interesterified fats aren't well understood at present, but they appear to have the same negative effect on lipoproteins and glucose as trans fats. However, more studies are needed, according to the AHA.
Source: American Heart Association. Consumer FAQ: "Bad" Fats (Saturated and Trans Fats). February 2008. http://www.americanheart.org.