Trans fats have garnered a lot of attention over the years, and for good reason. Are trans fats bad for you? Is there a difference between trans fats found naturally in foods and those created artificially? Are foods that say “0 grams trans fat” on the label actually devoid of any trans fats? What even is a trans fat?
It’s American Heart Month, and the perfect time to dive into nutrition and heart health. Last week I covered all things dietary cholesterol, and today we’re launching into trans fats. Again, just a reminder that there isn’t one magical thing to do to prevent heart disease. There are, however, many things that can help and the more you do the better!
What is trans fat?
To answer this we need to talk briefly about the difference between saturated and unsaturated fat. That’s right friends, we’re doing a chemistry review. Basically, saturated fat is fully “saturated” with hydrogen. It only has single bonds in the chemical structure, and is generally solid at room temperature. Unsaturated fats, however, contain at least one double bond and therefore are not fully “saturated” with hydrogen. This makes them liquid at room temperature. So an example of a saturated fat would be butter, and an unsaturated fat would be oil.
Trans fats occur both naturally (like in dairy products) and are artificially created and added to foods. To make a trans fat, hydrogen is added to an oil to make it more “saturated” and thus solid at room temperature (think margarine). Saturated fats and trans fats aren’t the same, however, but in simple terms you can kind of think of the process of making a trans fat like turning an unsaturated fat into a saturated one. Just remember that trans fats are different than saturated fats.
Are trans fats harmful?
If you haven’t read through the section “What’s ‘good’ and ‘bad’ cholesterol” in the dietary cholesterol post, now would be a good time to do that because we’re going to be talking a bit more about blood cholesterol. Another quick thing to note is that natural trans fats are not the same as artificial trans fats. Let’s start with artificial trans fats. We have good evidence that artificial trans fats raise LDL (“bad” cholesterol) and triglyceride concentrations (also not a good thing) while lowering HDL (“good” cholesterol). None of this is positive. Due to trans fats’ negative effects on blood cholesterol levels it is associated with greater risk for heart disease and cardiovascular events (like a heart attack or stroke). This is why, over the past several years, many food companies have been trying to reduce or eliminate trans fats in their products.
Okay, but what about natural trans fats? Does this mean dairy is dangerous?
Not so fast! While there is good research to suggest limiting or eliminating artificial trans fats in your diet, we don’t have as strong of evidence that natural trans fats are bad. In fact, there is some research that shows an inverse relationship between natural trans fats and cardiovascular disease. Meaning, people who ate more dairy were at a reduced risk for cardiovascular disease. There’s a lot of ongoing research to really pick apart natural trans fats, so hopefully we’ll know more soon! For now, there’s no need to fear trans fats in dairy. I wouldn’t go crazy on dairy though in the hopes that it’ll prevent heart disease. Like with most things, a moderate approach to dairy is probably best. If you like it, enjoy it with confidence. If you don’t, we also don’t really have strong enough evidence to suggest that you should start consuming more to prevent cardiovascular disease.
So how do I know if what I’m eating contains artificial trans fats?
Great question! The good news about artificial trans fats is that since they’re added to foods, they need to be listed on the nutrition facts panel. You can find the trans fat content of a food under the “total fat”. This number should be as low as possible, ideally 0. Note that this doesn’t necessarily mean that a product has no trans fat though. If a food product contains less than 0.5 gram of trans fat per serving they can round this number down to zero. This makes sense if you only eat one serving, or if you don’t eat many foods that contain trans fats. The downside to this though is that if you eat multiple servings of a food, or consume multiple different products that contain trans fats, you may be eating more trans fat than you’re aware of. To know if a food product actually contains trans fats, you need to look at the ingredient list. You won’t find the words “trans fat” listed here, but you may find “partially hydrogenated *insert oil here*”. That’s artificial trans fat. If you have high cholesterol, it is especially important to limit trans fat consumption. Check ingredient lists for “partially hydrogenated” oils to be sure that you aren’t eating a lot of trans fat. None of us actually need artificial trans fats, so if possible, it’s best to avoid them entirely. (This is probably one of the only times you’ll hear me say that about a food or ingredient.) If you have concerns about artificial trans fats, and whether or not they’re in the foods you regularly eat consult a Registered Dietitian Nutritionist for help!
TL;DR
There are two types of trans fat: artificial and natural.
Artificial trans fats increase “bad” cholesterol and decrease “good” cholesterol.
Natural trans fats do not appear to have the same negative effects as artificial trans fats.
A food may contain trans fats even if the label says “0 grams”. Look for “partially hydrogenated oil” in the ingredient label (this is trans fat).
You should limit your trans fat consumption as much as possible, or ideally eliminate it.