The Truth About Trans Fats

Fat is an important macronutrient, that when eaten in moderation is important for proper growth, development and maintenance of good heath (this of course refers to our good sources of fats such as oily fish, nuts, seeds, avocados etc). There are unfortunately the bad fats out there that do more harm than good. One in particular in the limelight at the moment is trans-fatty acids (TFAs). You may have heard of these fats in the media more so this year, which is due to the recent hype in America.

So what are these fats?

They come from two sources.

Hydrogenation - This is a process where they make liquid polyunsaturated fatty acids (‘good’ fats) into semi solid fats by adding hydrogen to the vegetable oil. This process changes the chemical shape of the fatty acids, resulting in a form which is more difficult to remove from the body.

The reason for using this method is that it improves the shelf life of the oil. It also allows conversion of the liquid oils into the solid fats needed to get the right consistency in foods such as cakes and pastries. Because this fat is so cheap you tend to find it is used in many fast food places and hence will be in many of your fried chips, hamburgers, pizzas etc. Other manufactured foods you will find TFAs in include pies, pastries, biscuits, buns, and margarines.

Naturally - TFAs are also created by mico-organisms in the fore stomach of cows and sheep so you will find TFAs in beef, lamb, and dairy products. At the moment there actually is no clear evidence that manufactured TFAs are more harmful than naturally occurring ones.

So you might be thinking what is all the fuss??

TFAs have been shown to raise total cholesterol levels as well as the blood levels of Low Density Lipoprotein, the bad component of cholesterol. In addition to this, TFAs also lower your good High Density Lipoprotein cholesterol. This in turn leads to your blood vessels clogging up with cholesterol and increasing your risk of Cardiovascular Disease.

Cardiovascular disease (CVD) is Australia's greatest health problem. It kills more people than any other disease (accounting for 47,637 deaths in 2004) and affected 3.5 million Australians in 2004-05. It contributes to significant illness, disability, poor quality of life and premature death, and is the most expensive disease group in Australia in terms of health expenditure.

Other claims about TFAs that still need further research as they do not have enough evidence supporting them include;

• Interference with immune function
• Inhibit the body's use of omega 3
• Associated with increased asthma
• Contributes to weight gain when the same caloric intake is consumed
• Interferes with enzymes the body uses to protect itself against cancer
• Interferes with enzymes needed to produce sex hormones

So how much is ok?

The World Health Organizations target is that TFAs make up <1% of our total energy intake, which equates to 2-3g/day. You would be glad to know that Australia’s average intake is 0.6%. This compares to 2.6% total energy intake in the USA. So you can see why there is so much hype at the moment from America!

As long as you are only having TFA foods occasionally and replacing them with good sources of fat in your diet you’ll be doing your body a huge favour.

Some interesting facts;

• Denmark banned TFAs in 2003, making it illegal for any food to contain more than 2% of TFAs.
• In USA TFA levels must now be declared on food labels. The UK is pushing for similar requirements.
• Australian manufacturers aren’t required to include TFAs on the label unless they make a claim about cholesterol or unsaturated fats.

Note: some imported foods say ‘partially hydrogenated’ vegetable oils. This gives you at least some indication that the product contains trans- fat, though you still won’t know how much.

The cheapest and easiest way to remove TFAs from manufactured products is to use other vegetable oils such as palm oil. This can then raise the saturated fat intake of Australians even more. What’s worse is that some companies are already doing this because they are scared of the recent hype.

There are new oil products available which reduce TFAs and saturated fats and which some companies are already using. The only problem is that there is a supply issue as it will take time to grow these crops and meet the high demand.

The Thermomix is a great appliance as it allows you to avoid TFAs by making your own healthy meals at home and knowing exactly what is going into them. In the time it takes one to drive down to the shops and buy take away you could have made a gourmet meal in your Thermomix without even breaking a sweat!