Trans Fat Becomes a New Fat to Avoid
~ July 2003 No.170 ~
The war on fat is heating up. There is good fat, bad fat and now it seems there is very bad fat. Consumers have gotten the message that they have to cut back on the total amount of fat they have in their diets. Right now more than 35% of total calories come from fat in the North American diet. Many health groups have recommended that this drop. Suggestions as low as fat equal to 10% of the diet calories has been made.
Polyunsaturated fats - the kinds that are found in vegetable oils and mono-unsaturated fats - the fat found in olive oil - are considered good fats. Some of the polyunsaturated fats are “essential”. Our bodies are able to synthesize some fats , but not essential fats, and therefore, we must get them through the diet.
Recently much attention has been played to trans fatty acids or trans fats. Trans fats are found in many processed foods although they can be found in small quantities in such foods as milk and meat. Spreading vegetable oil on bread would be one way of avoiding trans fats, but most of us like margarine. Trans fats are produced during the conversion of liquid oils to solid fats. Soft spreadable margarines contain little or no trans fat, but hard margarine and cooking fat is high in trans fat. During the hydrogenation process, some unsaturated fatty acids are produced that have a trans configuration geometry. Most fatty acids have a cis configuration geometry. This small change in geometry means that the body cannot metabolize trans fats as it does with other fats that are consumed.
Trans fat is bad because it Lowers the “good” HDL cholesterol in a dose response manner (the higher the trans level in the diet, the lower the HDL cholesterol in the serum). In addition it also raises the LDL cholesterol in a dose response manner. Because of this double effect, cutting trans fat consumption is a priority and health officials are reluctant to recommend an upper limit to acceptable trans fat consumption.
Health regulatory officials in the United States have recently declared that the amount of trans fat in a food will now have to be indicated on the food label. This added bit of information will allow shoppers to clearly see how much trans fat they are getting. This new regulations has already prompted several food manufacturers to declare that they will be soon eliminating trans fat from their products. Cakes , cookies, pies and bread are the major sources of trans fats in the American diet.
|Food||grams trans fat /serving|
|Chocolate chip cookies:||1.2-2.7|
|French fries (fast food):||0.7-3.6|
Trans Fat: The Facts CDC pdf fact sheet