Unknowingly, part of your weekly diet most likely contains trans fats. What are trans fats, you ask?
Trans fatty acids or trans fats are formed when manufacturers turn liquid oils, usually palm oil, into solid fats. Manufacturers create trans fats using a process called hydrogenation in which hydrogen atoms are added to vegetable oils, converting them into solid fats. This process increases the shelf life and flavour stability of foods.
While trans fats do exist naturally in some foods, it is the industrially produced trans fats found in many processed foods that are the largest cause for concern. Like saturated or animal fats, trans fats contribute to clogged arteries, increasing the risk of both heart disease and stroke. They also increase levels of “bad” (LDL) cholesterol, and some studies have indicated that trans fats may also increase the risk of diabetes. Effectively, for consumers, consuming trans fats is like eating candle wax: they can’t be broken down in the digestive system so accumulate and clog up arteries.
Many countries around the world have a total ban or a limit on the amount of trans fats consumed or at least minimum labelling requirements enabling consumers to make more informed decisions. Unfortunately none of this applies in Australia. In Austria and Iceland there is a total ban on trans fats, and Sweden is in the process of a total ban. In 2003, Denmark became the first country in the world to introduce laws strictly regulating the sale of many foods containing trans fats by limiting the amount of trans fats in foods to a maximum of 2%. This legislation has made Denmark the only country where it is likely that people will eat “far less” than 1 g of non-naturally occurring trans fats per day. Over the past 20 years, trans fat consumption in Denmark has decreased from an average daily intake of 6g per person to only 1g per person, which is linked to a 50% decrease in deaths from heart disease over that period. In 2006, New York City was the first city in the United Sates to ban trans fats in restaurant food. Many countries and cities around the world have similar policies.
Oleic acid is a fatty acid that occurs naturally in various animal and vegetable fats and oils. When trans fats are industrially produced, the arrangement of the molecules in the fatty acids are altered, causing changes to occur to the chemical and physical properties of the fat. For example, the trans fatty acid, elaidic acid, and naturally occurring oleic acid have the same chemical formula but they have different chemical and physical properties:
Oleic acid (natural fatty acid):
- Has a melting point of 13.4˚C
- Is liquid at room temperature, because the molecules are loosely packed together
Elaidic acid (man-made fatty acid)
- Has a much higher melting point of 45˚C, much too high to melt in the mouth
- Is solid at room temperature, as the molecules are much more tightly packed
This also explains why trans fats have been increasingly used in the processed food industry: they make the food last longer and decrease refrigeration requirements.
Trans fats can be found in a long list of foods including vegetable shortening, margarine, crackers and biscuits, cereals, lollies, baked cakes, cookies, muesli bars, chips, snack foods, salad dressings, fats, fried foods, compound chocolate and many other processed foods. Naturally occurring trans fatty acids are found in small quantities in some foods including beef, pork, lamb, milk other dairy products, but the vast amount of trans fats consumed are from industrially-made sources.
Today trans fats are found in approximately 40% of the products on our supermarket shelves. Almost half of trans fat intake comes from pre-made cakes, biscuits, bread and other pastry products, while over 15% comes from margarine alone. The American Heart Association recommends that no more than 1% of a persons’ total daily calories be from trans fats.
Extract from NSW Food Authority – Trans Fatty Acids Survey May 2008
Products with greater than 2% Trans Fatty Acids
Trans fatty acid levels above 2% were found in 36 (41.9%) food products. None of these products contain ruminant fats and it would be expected that the trans fatty acids originated from hydrogenated fats (that is, industrially-made trans fats). Products from the following food categories had trans fatty acids concentrations greater than 2%:
• Potato crisps
• Shelf stable cakes
• Potato chips
• Chicken nuggets
• Processed fish
A donut sample had the highest concentration of trans fatty acids at an average of 28.6% ± 5.4%. Other products that had very high concentrations of TFA included another donut sample (average of 8.9%) and samples of shelf stable cakes with an average of 9.6% (range from 2.9 to 23.5%).
In the past, the Australian Federal Government has announced that it wishes to pursue policies to reduce trans fats and saturated fats in fast foods, with a September 2007 timetable, however this was never enacted into law. The federal government has also defined trans fats very narrowly, as being only those that contain a trans bond, disregarding a broader definition which has been recognised by the United States, EU and other nations when passing laws against trans fats. This narrow definition will lead to some trans fats possibly not being classified correctly or being included in calculations of trans fat levels in foods.
One of the main uses of trans fats is as a replacement for cocoa butter in the production of compound chocolate. Manufacturers of compound chocolate use hydrogenated and fractioned vegetable oils such as soyabean oil, rapeseed oil, coconut oil and palm oil, which contain high levels of trans fatty acids. Alarmingly, some compound chocolates have been found to have trans fat levels of up to 50%.
There is also the other side of the coin with Australia Zoos attempting to stop the eradication of rain forests which are being cut down and replaced with palm oil plantations in many parts of the world. They are currently running a campaign, “Don’t Palm Us Off” to raise awareness for the unsustainable palm oil production that is destroying orang-utan and the poor labelling of palm oil in supermarket products.
You now have the information on hand to make an educated choice about not only the ingredients you use but also the processed products you purchase.