What Are Polyunsaturated Fats, and Are They Healthy?
- Nov 10, 2016
- 3 min read
Fats are typically grouped together has a nutrient to be avoided, and often get a bad rep. But, not all fats are created equal. Yes there are those select few that should be limited or avoided, but there are also a select few that benefit your body in more ways than one. There is much to learn about each of these fats, and therefore today we will focus on just one... Polyunsaturated fats.
What are polyunsaturated fats?
On a molecular level, fats are made up of chemical chains containing carbon, hydrogen, and oxygen. The way the chemical chains are arranged determines how saturated or unsaturated they are, as well as what type of fat they are known as. Polyunsaturated fatty acids are characterized by a chemical chain missing two or more hydrogen pairs, and they also contain at least two double bonds. As illustrated in the photo to the left, there is a noticeable difference between the chemical structure of a saturated fatty acid and a polyunsaturated fatty acid. The saturated fatty acid is a straight structure, while the polyunsaturated fatty acid is bent at multiple places. In addition, saturated fatty acids contain more hydrogen pairs as well as less double bonds which are illustrated by the equal sign. So what does this mean? The difference in chemical structure accounts for their difference in health benefits as well as the way they are seen by the human eye. Saturated fatty acids are typically solid at room temperature such as bacon fat, butter, etc., while unsaturated fatty acids are liquid at room temperature like olive oil and canola oil.
What are the sources of polyunsaturated fats?
Unsaturated fats are liquid at room temperature, and therefore mostly all foods containing polyunsaturated fats contain oil. Sources of polyunsaturated fats include soybean oil, corn oil, safflower oil, sesame oil, sunflower oil, nuts and seeds such as walnuts, sunflower seeds, and flaxseeds. Additional sources of polyunsaturated fats include tofu and fatty fish easily remembered by SMASH (salmon, mackerel, anchovies, sardines, and herring).
Why are polyunsaturated fats known to be heart healthy?
You may have heard of omega-3 and omega-6 fatty acids. These fatty acids are actually a type of polyunsaturated fat and are considered to be essential. This means that our bodies do not have the ability to make these fats and must be consumed through the diet. Through the typical American diet, omega-6 fatty acids are never worrisome and often consumed in large amounts. Omega-3 fatty acids on the other had tend to be lacking in the American diet which has been shown to be correlated with heart disease.
Studies have shown that polyunsaturated fats including omega-3 and omega-6 fatty acids lower total cholesterol, and also lower LDL (low-density lipoprotein) cholesterol (bad cholesterol). In addition, polyunsaturated fats are important in brain function, and help to prevent blood clotting.
But what is the connection between polyunsaturated fats and heart disease? Well, an inflammatory response is needed in order to form plaque within the artery walls. Polyunsaturated fats are capable of producing eicosanoids which are derived from omega-3 and omega-6 fatty acids. Eicosanoids have anti-inflammatory effects which reduces the risk of heart disease by minimizing the risk of plaque formation in the arteries.
References:
1. Duff Larson R. Complete food & nutrition guide. 4th ed. Hoboken, NJ: John Wiley & Sons, Inc.; 2012.
2. Barnes-Svarney P, Svarney T. The handy nutrition answer book. 1st ed. Canton, MI: Visible Ink Press; 2015.
3. American Heart Association. Polyunsaturated fats. American Heart Associated Website. http://www.heart.org/HEARTORG/HealthyLiving/HealthyEating/Nutrition/Polyunsaturated-Fats_UCM_301461_Article.jsp#.WCS_uDKZPVo. Updated September 16, 2016. Accessed November 10, 2016.
4. Gropper S, Smith J. Advanced nutrition and human metabolism. 6th ed. United States: Wadsworth Engage Learning; 2013.
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