You may be wondering, “what are trans fats?” Of all the fats to avoid, this one tops the list. We hear everywhere about the dangers of this unhealthy ingredient in our diet. They are vegetable oils that are made solid through hydrogenation, a process that turns what may have once been healthy liquid oils into unhealthy solids.
Unsaturated fats such as vegetable oils (sunflower, corn, soy and especially cottonseed) are heated to high temperatures, with an added catalyst such as nickel, palladium, platinum or rhodium. Hydrogen is then bubbled, under pressure, through the oil, which is then filtered to remove the metal. This process of hydrogenation creates a trans-fat filled solid.
Partially hydrogenated oils are widely used in processed foods such as margarine, baked goods and snack foods in order to extend shelf life, as well as being used for frying. The food industry loves it because it is a stable fat, doesn't go rancid as quickly as unhydrogenated oil, can be used for high-temperature frying, extends shelf life, and increases "mouth feel" to foods that would otherwise taste like cardboard.
Harvard researchers have estimated that trans fats may be responsible for upwards of 30,000 U.S. deaths each year from coronary heart disease. They lower “good” HDL cholesterol, raise high “bad” LDL cholesterol, increase blockages in the arteries, increase blood insulin levels, encourage insulin resistance, lower immune response and cause changes to the structure of our cells.
The results of a study published in the April 2006 New England Journal of Medicine found that:
On a per-calorie basis, trans fats appear to increase the risk of coronary heart disease more than any other macronutrient, conferring a substantially increased risk at low levels of consumption (1 to 3 percent of total energy intake). In a meta-analysis of four prospective cohort studies involving nearly 140,000 subjects, including updated analyses from the two largest studies, a 2 percent increase in energy intake from trans fatty acids was associated with a 23 percent increase in the incidence of coronary heart disease....
To keep your consumption to a minimum, try to avoid processed foods, especially baked and fried foods, and examine the label of your salad dressing bottle to be sure it includes no partially hydrogenated oil.
If you thought trans fat was bad, interesterified fats are even worse. Manufacturers will often use this type of fat so they can claim their products contain “no trans fats”, however, this fat is even more harmful, containing fully hydrogenated oil.
Interesterification (say that three times fast!) rearranges the fat molecules so the fat remains solid at room temperature while also lowering its melting point. It's true that this process gets rid of the trans fats that were created during partial hydrogenation, but its health effects are even more damaging!
Interesterified fats were found to depress the level of HDL (good cholesterol) far more than trans fat, while raising blood glucose levels and depressing levels of insulin, which suggests that interesterified fats could lead to diabetes. Studies found that this type of fat interferes with the ability of your pancreas to produce insulin. After only four weeks of consuming interesterified fats, the blood glucose levels of a study's volunteers rose 20 percent, while insulin levels dropped 20 percent.
Hydrogenated or partially hydrogenated oil, such as that found in margarine, should be avoided at all costs.
Unfortunately, you are not likely to find the term "interesterified fat" on many food labels. The FDA has ruled that, instead of using the word "interesterified," manufacturers can use the terms "stearic rich" or "high stearate" instead. Also, fully hydrogenated vegetable oil, palm oil or palm kernel oil may be interesterified. Instead, buy products that use one of the healthy cooking oils, such as olive oil.
Some peanut butters now are made with interesterified fats, so be sure to read the label when you buy it to be sure it contains only peanuts and salt and no hydrogenated oil. Pretty much any food label that says it contains vegetable oil is almost certain to have either trans or interesterified fats.
The best way to avoid trans fats is to cook for yourself as often as possible, avoiding processed food. If you use one of the natural saturated fats such as butter or lard, or a healthy unsaturated fat like olive oil, it will be far better for your health.
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