Many decades ago, people began to think up various new and innovative ways to preserve food, so that it didn’t go off and to extend its shelf life. One such method included preserving food with oil, so that it could remain fresher for longer, withstand heat and reduce any bad smells that may arise from the food going bad. This method also reduced costs involved with storage. The transformation of the oil also meant that it improved the flavour of the oil, at the same time as making the food softer and more palatable. The technique was therefore utilized when making numerous types of food, such as fast foods, which require oil for deep frying ingredients like chicken, potatoes and donuts. Alternative uses for the oil were in the production of bread, baked goods, dried snacks and artificial creams, for example.
Generally speaking, natural plant oils are made up of unsaturated fatty acids. Because of this, the oxygen present in the air is able to enter the substance and react with the oil, leading it to expire and give off a bad smell. Thus, the transformation of the oil is carried out by adding hydrogen into the unsaturated fat, until the fat begins to take on the quality of saturated fat. It is this semi-rigid, semi-liquid quality which makes the oil suitable for use in making various types of food. The result of this synthetic additive process is what we call “trans fat” or “partially hydrogenated oil”. Additionally, when looking on food labels for this ingredient, it will tend to be referred to as ‘hydrogenated oil’.
That being said, trans fats do sometimes occur naturally, but such examples are rare. They include vaccenic acid and conjugated linoleic acid. Trans fats are also naturally occurring in red meat and in dairy products farmed from bovine animals. However, research into naturally occurring trans fats is yet to find that such fat is as bad for the body as synthetically produced trans fats.
Numerous studies have concluded that consumption of synthetically produced trans fats is dangerous, as it can lead to coronary artery disease. It does this by supporting the work carried out by cholesterol acetyltranferase, an important enzyme in the metabolism process of cholesterol which increases the amount of LDL (bad fat) while at the same time decreasing the amount of HDL (good fat) in the body. This process also leads to an increase of triglyceride in the bloodstream and increases inflammation throughout the body.
Currently, guidelines have been released by the United States Food and Drug Administration (FDA), which restrict the use of oils that have undergone the hydrogenation process, as they cannot be guaranteed to be safe. Additionally, other countries have begun to place legal limitations on the amount of trans fats being consumed by reducing their use in food production. Instead saturated fats are being used, including pork fat, palm oil and fully hydrogenated oil.
The reasons behind many manufacturers’ turning to trans fats were in the first place the ability to extend a product’s shelf life and to withstand heat without a reduction in quality. Furthermore, the products taste similar to those made from oil taken from red meat, but most importantly, manufacturers prefer trans fats because of the low cost. It is seen as a low-investment, high-return product, therefore many manufacturers have turned to trans fats in the manufacturing process of their food products.
Even small amounts of trans fats can increase the levels of LDL (bad fat) while reducing HDL (good fat) levels. This process causes a constriction and inflammation within blood vessels, which can lead to coronary artery disease. Moreover, trans fats plays a key role in increasing the risk of people developing diabetes.
Ideally, the total amount of both trans fats and saturated fat consumed on a daily basis should not exceed 20 grams. In people who are at a greater risk of cardiovascular disease, the recommended daily limit should be reduced further to less than 15 grams.
M.D.,Faculty of Medicine, Chulalongkorn University. Faculty of Medicine Chulalongkorn University , 2002