Trans Fat Explained
Let’s take a few minutes to explain trans fats and what I think you should know about them. They are one of the 3 major types of dietary fat that you should understand, so I’m going to take a few minutes to explain what they are and how they can affect your health.
The first thing I want to talk about is structure, since that is important to understand how it’s different from saturated fatty acids and mono and polyunsaturated fatty acids. In this picture you are looking at a complete trans fatty acid on the bottom. Fatty acids contain a long tail which is composed of carbon and hydrogen atoms. At the head of any fatty acid is what’s called a carboxyl group. They are the same on all fatty acids so I won’t spend any more time talking about them, because they don’t define the distinction between the different fatty acids or types of fat.
What makes this a trans fatty acid is the carbon-carbon double bond where the red arrow is pointed. Each black line represents a bond between two atoms, so when you see two, it represents two double bonds between two atoms. The trans fatty acid is referring to a carbon-carbon double bond, which is the red arrow, and it specifically refers to the configuration of that double bond. It can “bend” two different ways, one is called trans where it bends across itself, or cis when it bends away from itself which is depicted in the top fatty acid. Cis generally occurs in nature and trans is generally more of a manufactured product. The significance of this double bond in the trans configuration is that it allows trans fats to stack very tightly, making it harder for your body to metabolize them.
One other thing I want to point out is that while trans fats are technically unsaturated, they are not the same as mono and polyunsaturated fat, and that has to do with the cis configuration of those fatty acids and is explained in the unsaturated post. The number of carbon atoms in the chain can vary also, which can also affect how your body metabolizes the fatty acid.
Some trans fatty acids occur naturally in foods, especially those of animal origin, although most trans fatty acid consumption is a result of the industrial hydrogenation of polyunsaturated fatty acids. (This should be a red flag, it’s a pretty good rule of thumb that if it doesn’t occur in nature it’s probably not as good for you as natural alternatives). Companies and food producers have a tendency to use trans fats because they have a long shelf life and are solid at room temperature.
Negative Health Effects
1. Multiple studies have shown adverse effects in diets high trans fat. Similarly, studies have found replacing trans fats with mono and polyunsaturated fat can reverse many of these these negative effects.
2. They tend to raise LDL cholesterol, the bad one, and lower HDL cholesterol, the good one.
3. Trans fatty acids also appear to interfere with desaturation and elongation of omega 3 fatty acids. In other words, they can diminish the effectiveness of omega 3 fatty acids.
4. Studies have linked trans fatty acid consumption with increased risk for coronary heart disease, myocardial infarction or heart attacks, and stroke.
5. Trans fat has also been associated with an increased risk of developing diabetes.
Common Dietary Sources
margarine, fried foods like french fries and donuts, baked goods including pastries, pie crusts, biscuits, pizza dough, cookies, crackers and shortenings. You can identify whether the food(s) you are eating have trans fat by looking at the food nutrition facts and also looking for partially hydrogenated oils in the ingredients.
Note, The American Heart Association recommends no more than 1% of your total calorie intake consist of trans fats.