Definition of trans fat
Trans fat is a specific type of fat formed when liquid fats are made into solid fats by the addition of hydrogen atoms, in a process strangely enough known as hydrogenation. That being said, small amounts of trans fats are found naturally in certain animal based foods. Trans fat was originally added to foods to increase the shelf life. Trans fat does not stand for “Transformed fat” (except maybe in the mind of someone trying to market this), but comes from the fact that the hydrogen atoms in the double bond are actually across from each other (see below). This comes from the Latin meaning of trans, which is across.
 The FDA has estimated that the average American consumes 5.8 grams of trans fat per day!
What are the health effects of trans fat?
An Institute of Medicine/National Acadamies of Science report recently recommended that “trans fatty acid consumption be as low as possible while consuming a nutritionally adequate diet.” Trans fat gives a double dose of bad news, as it increases so-called bad cholesterol, which is actually Low Density Lipoprotein (LDL) and decreases so-called good cholesterol, which is actually high density lipoprotein (HDL). Most experts agree that it is the ratio of LDL to HDL which determines your risk factor for heart disease, so it is good for anyone interested in a healthful diet to reduce the intake of trans fat. Other types of fat have not been shown to decrease HDL, but saturated fats have been shown to increase LDL. It is advisable to decrease the daily intake of saturated fat AND trans fat and not give up by increasing the other.
One thing to remember is that there is no daily recomended value for trans fat. It potentially is required in small amounts in our diet, but certainly not at 5.8 grams per day!
Truth in Advertising?
In the current FDA rule trans fat does not have to be listed if the total fat in a food is less that 0.5 grams per serving and no claims are made about the fat, fatty acids or cholesterol content. The result of this rule is that you could consume up to 0.49 grams per serving and think you are being good to yourself. I picked up some chips at the supermarket, and they actually had a label on the front advertising “0 grams trans fat” and I bought them only to get home and realize that partially hydrogenated soybean oil was on the ingredients list! What to do? Read the ingredients and look for the word “shortening” or the words “hydrogenated” or “partially-hydrogenated.”
If below the threshold of 0.5 grams, a footnote will be on the label stating that the food is not a significant source of trans fat. If the daily value and the extent of health risk due to trans fat consumption is not defined then how can it be defined as “not a significant source”? What is the context for that statement?
Steps to minimize the amount of trans fat in your diet
Here are some simple steps you can take to minimize the amount of trans-fat in your diet:
- Read the label and compare foods – This is not always as easy as you think as the current rules may allow a manufacturer to label as 0g transfat on the label, when there are actually up to 0.49g per serving (see below).
- Switch to monounsaturated fat and polyunsaturated fat. These fats are found in oils (olive, canola, and others) and nuts. These fats not only do not raise LDL, but have health benifits when consumed in moderation. A related suggestion is to switch to vegtabale oils. I use olive oil when cooking and usually corn or sunflower oil for everything else.
- Many processed and ready to prepare foods contain trans fat, such as microwave popcorn. If you use corn oil and a large pan on the stove, it tastes better anyway…
Links for more information:
Trans Fatty Acids in Nutrition Labeling, Nutrient Content Claims, and Health Claims – FDA final rule
Ban Trans Fats – The Campaign to Ban Partially Hydrogenated Oils
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