Partially Hydrogenated Oils

What’s the deal with Partially Hydrogenated Oils? 

We hear a lot about trans fats and hydrogenated oils in the media, but what exactly are they?

Hydrogenation

To understand what hydrogenation is, we must first start at the basics: fat and oil. Oil and Fat are both composed of fatty acids as some of us might remember from high school biology. While they share this structural similarity, the difference that we are looking for between fat and oil is that fat is solid at room temp, while oil is liquid.

There are two types of fatty acids: saturated and unsaturated. The difference between the two is in the amount of hydrogen they contain. The more hydrogen they contain, the more solid the substance becomes. Saturated fatty acids contain more hydrogen and are, therefore, more solid than unsaturated fatty acids. We can remember this because both Saturated and Solid start with the letter “S”. 

Each oil is made up of a combination of saturated (solid) and unsaturated (nonsolid) fatty acids.  The higher the saturated fatty acid content, the more solid it is at room temperature, such as palm oil. Conversely, the lower the saturated fatty acid content, the less solid it is at room temperature, such as soybean oil. 

So why do we care? 

Because food manufacturers prefer oils that are more solid at room temperature because it gives their products a longer shelf life.  And unfortunately, cheap oils, like soybean oil, are not solid at room temperature due to the lower amount of hydrogen atoms (less saturated fatty acids).

To combat this problem, someone somewhere invented “hydrogenation.”  This is a process where they bombard cheap oils with hydrogen atoms in order to change its molecular structure.  By doing this, they create an inexpensive oil that is solid enough at room temperature, but still remains soft. This level of hydrogenation is called “partially hydrogenated.” This changes the chemical structure of the unsaturated fatty acid into a trans-fatty acid. 

So, to sum it up, a trans-fatty acid is an unsaturated oil that is hydrogenated to create a more solid substance to increase shelf-life and keep costs down. If they continue to infuse the molecule with hydrogen, they turn the unsaturated fatty acid into a saturated fatty acid.

Health Consequences

It turns out that the trans-fatty acids (partially hydrogenated oils) created by shoving just enough hydrogen into an unsaturated fatty acid is quite unhealthy, much more so than a saturated fatty acid. It has been shown to contribute to cardiovascular disease, raise bad cholesterol, lower good cholesterol, and increase inflammation in the body. As a result, in 2015 the FDA banned the use of these partially hydrogenated oils in food.  

We can applaud the FDA for banning this unsafe and unhealthy practice. We can also use this as a reminder that not all is bad with the FDA, and we should celebrate these public health wins.

Sites/More Info:  

Direct Final Rule to Revoke Use of Partially Hydrogenated Oils in Foods | FDA

Trans fat is double trouble for heart health - Mayo Clinic