Fat is an essential part of a healthy diet, and plays an important role in many basic functions in the body. Both humans and animals rely on fat as a major source of energy.
It's also used to absorb vitamins and minerals, support the growth and development of cells, maintain brain and nerve function, and keep skin and tissue healthy.
But despite the fact that fat is vital to our health, there's still some confusion about different types of dietary fats. In our recent post on hyperlipidemia in pets, we looked at the concept of "good" fats vs. "bad" fats. We also explored the differences between saturated and unsaturated fats in a previous blog post.
In today's post we'll turn the spotlight on hydrogenated fats. Keep reading to find out what they are, and how they differ from other types of fats. We'll also explain why they are considered by many doctors to be the worst fats for our health.
In order to understand what hydrogenated fats are, it's important to look at fat composition. Fats are composed of carbon atom chains with hydrogen atoms attached to them. The terms saturated, monounsaturated, and polyunsaturated refer to the degree of hydrogen saturation of the fatty acid carbon chain.
When a chain of carbon atoms is fully connected with hydrogen atoms, it is considered a saturated fat, or "saturated" with hydrogen atoms. Unsaturated fats have missing hydrogen atoms. This means they have double bonds between carbon atoms in the fatty acid chain. The composition of unsaturated fats makes them less stable than saturated fats, and prone to spoilage and rancidity.
How Hydrogenated Fats Are Created
Unsaturated fats in foods spoil easily and present a problem for manufacturers. In response to this, food scientists attach hydrogen atoms to unsaturated fats in a process known as hydrogenation. This changes the double bonds to single bonds, and makes the food less vulnerable to rancidity.
Full vs. Partial Hydrogenation
The process of hydrogenation can produce fats that are fully or partially hydrogenated. Full hydrogenation means that all of the double bonds in an unsaturated fat are turned into single bonds. When this happens, fats become solid at room temperature. By comparison, partial hydrogenation means that only some of the double bonds are turned into single bonds. This makes fats semi-solid at room temperature.
Since fully hydrogenated fats are solid at room temperature, manufacturers blend them with liquid oils to soften them. Fully hydrogenated fats contain very little trans fats (more on this in a moment). This means that they are less damaging to our health than partially hydrogenated fats. However, they are man-made and may contribute to health problems in people and pets.
In the next section of this post, we'll take a look at why the trans fats in partially hydrogenated fats are especially harmful to health.
What Are Trans Fats?
Trans fats, or trans fatty acids, are a type of saturated fat that occurs naturally in certain foods. For example, meat and dairy products contain small amounts of trans fats. Natural trans fats found in animal products are not harmful. However, artificial trans fats formed through the process of partial hydrogenation are very damaging to health.
The natural shape of the unsaturated fatty acid at its double bonds is a curve or a kink. At this curve, the hydrogen atoms both stay on the same side. This is called the cis position of the hydrogen to its carbon atoms.
During the chemical and physical process of partial hydrogenation, the hydrogen atoms rearrange themselves. When this happens, they move from their natural position (cis) to a new position located across from each other. This position is called trans. With partial hydrogenation, most of the double bonds of the unsaturated fats remain. However, their hydrogen atoms change position to become trans – or across from each other.
Trans fats have been shown to increase blood cholesterol levels. In addition, they increase LDL ("bad cholesterol") and lower HDL ("good cholesterol"). Trans fats also contribute to atherogenesis, a process in which fatty deposits form in the arteries, gradually constricting them.
Trans fats cannot be processed by humans, as our bodies do not have the protein enzymes needed to break down these artificial fats. In fact, trans fats have been linked with numerous health problems including heart disease, diabetes, and cancer. This is why they are considered by many doctors to be the worst fats you can eat.
The Bottom Line
When it comes to making healthy choices for ourselves and our pets, it's important to avoid hydrogenated fats and trans fats. These types of fats are found in a wide range of products, including margarine, vegetable shortening, fried foods, and baked goods. For this reason, it's vital to read nutrition labels when shopping for food.
Want to find out why coconut oil is a healthy saturated fat that supports the health of pets and people? Check out our previous post, Coconut Oil – Is It Really Healthy?