To fully understand what trans fat is, or what are trans fats in your food, you need to know some basic chemistry.
But don’t worry if you don’t – because it is not vital for the average consumer to understand chemistry and the chemical structures of fat molecules.
It is far more important to just know that:
- trans fats are extremely harmful to
health, causing a long list of health problems including heart disease,
obesity, diabetes, various types of cancer, and so on
- even very tiny amounts are harmful so you should avoid them as much as possible
- trans fats are found in products such as margarine, vegetable shortening and partially hydrogenated vegetable oils
- trans fats are used for making a very wide range of food
products including bread, biscuits, cookies, pastries, cakes, chocolate,
peanut butter, non-dairy creamer, ice-cream, etc.
- trans fats are also often used for deep frying, Thus, they are commonly found in french fries, fried chicken and other fried foods – in fast food restaurants and even high-end restaurants.
Chemistry made simple
If you really wish to understand what is trans fat / what are trans fats… let me make it simple for you.
Trans fats are fat molecules whose atoms are arranged differently from regular fat molecules.
Fat molecules are basically made up of hydrogen and carbon atoms in a chain. Some chains are short and they are called short-chain fatty acids, or short-chain triglycerides (this is the chemical word for “fats”). Likewise, there are medium-chain fatty acids / medium-chain triglycerides as well as long-chain fatty acids / long chain triglycerides.
In regular vegetable oils the chains are bent – and so the hydrogen atoms are on either side of the chain. Because of the bent, the fat molecules cannot be packed closely together, so the fat is liquid.
In trans fats, the chain is somewhat straightened, with a slight kink. Because of this, the fat molecules can be more closely packed together and the fat becomes harder – the way margarine is harder than vegetable oil, even though margarine is made from liquid vegetable oil.
Natural vs artificial trans fats
Many writers, when they write about what is trans fat / what are trans fats, describe them as artificial fats. In some of my articles, I, too, use the terms interchangeably.
Strictly speaking, this is not correct because there are also natural trans fats that occur in products such as milk, cheese, meat and certain vegetables and fruits. Not all trans fats are artificial.
However, natural trans fats occur in very small amounts and they are not known to cause any health problems. In fact, some of these natural trans fats might be called good trans fats, because they have beneficial properties such as anti-cancer effects.
So for all practical purposes, when we discuss what is trans fat, it is the artificial trans fat that we are talking about – and should be concerned about.
What is hydrogenation?
Related to the question of what is trans fat, is the question, what is hydrogenation.
This is the process of adding more hydrogen atoms to the fat molecules. The purpose of hydrogenation is to turn liquid oil into a solid, like wax, or a semi-solid, like grease.
But again, there is no real need to understand this in terms of chemistry.
What’s important to know is:
- hydrogenation is a very unnatural process that uses very
high heat – about 500ºF or 260ºC – as well as high pressure. At such
high temperature and pressure, oil molecules become damaged and very
harmful to health
- hydrogenation also requires the use of catalysts
(substances that promote chemical reactions) such as nickel, and these
catalysts are toxic to humans. They are removed after hydrogenation, but
traces inevitably get left behind
- trans fats are mainly produced during the process of hydrogenation.
However, we should note that trans fats are not ONLY formed during hydrogenation. Other processes, such as when commercially produced vegetable oils are deodorised – again using high heat and high pressure – can also cause the formation of trans fats.
Thus, ordinary vegetable cooking oils might also contain small amounts of trans fats. The amounts are usually small, so not many people are concerned. However, whether or not these oils contain trans fats, they are also very harmful to health because of the unnatural, high-heat, high pressure treatment that they undergo.
What is partially vs fully hydrogenated fat?
Ironically, trans fats are present only mid-way during the hydrogenation process.
If the process is carried out till the end, meaning if the oil is FULLY HYDROGENATED, trans fats are no longer present.
The explanation for this is a bit more complicated…
Earlier, when we examine what is trans fat, we learn that regular fats have molecules that are bent, whereas trans fats have molecules that are somewhat straightened, with a slight kink.
When the fat is fully hydrogenated, however, the bond – the place where the molecule is either bent or kinked – is broken up. There is no longer a situation where the fat molecule is straight but kinked – what is trans fat.
Instead, the molecule chains become straight lines. As a result, they are very closely packed. The fat hardens and is said to be saturated.
Thus, trans fats are found only in PARTIALLY HYDROGENATED oils.
However, if you see only the word “hydrogenated” on food labels, this is just a short-form for partially hydrogenated. It still means that there are trans fats.
Fully hydrogenated oils are very hard and they cannot be eaten. Just because they no longer contain trans fats does not mean that they are healthy – again because of the very unnatural process that they have gone through.
So be careful about this. Some manufacturers of vegetable shortening now use fully hydrogenated oils – which are hard and inedible – mixed with liquid oil.
This way, they are able to offer a semi-solid, greasy substance that does not contain trans fats. And unfortunately, many people are mistaken in believing that such products are healthy. They are not!
What is trans fat? A summary
To summarise, it is not vital for consumers to fully understand what is trans fat in terms of their chemistry.
However, it is useful to understand and to know, not just what is trans fat, but related issues such as:
- what is hydrogenation
- what is the difference between partial and full hydrogenation
- how are trans fats formed
- where are trans fats found
- and so on.
In other words, we need to know what foods are safe to eat and what foods we should avoid. That, ultimately, is more important than a chemical understanding of trans fats in the molecular sense, most important is how to avoid them in your food!