Trans fatty acids (TFAs), occur both naturally in foods and can be formed or added to foods during manufacture. Naturally occurring TFAs are found in some animal products including butter, cheese and meat. Manufactured TFAs (also known as artificial TFAs) are formed when liquid vegetable oils are partially hydrogenated or 'hardened' during processing to create spreads such as margarine, cooking fats for deep-frying and shortening for baking. Some TFAs are also formed during high temperature cooking.
Are trans fatty acids harmful?
There is strong evidence that TFAs increase the amount of 'bad' low-density lipoprotein (LDL) cholesterol in our blood, a major risk factor for coronary heart disease. Also, TFAs may decrease the levels of 'good' high-density lipoprotein (HDL) cholesterol in blood.
The World Health Organization (WHO) recommends that no more than 1 per cent of our daily energy intake (kilojoules) should come from TFAs.
How much trans fatty acids do we eat?
Monitoring of TFAs in the Australian and New Zealand food supply has found that Australians obtain on average 0.5 per cent of their daily energy intake from TFAs and New Zealanders on average 0.6 per cent. This is well below the WHO recommendation of no more than 1 per cent. It is also below the levels in many other countries. However, the monitoring study also found that intakes of saturated fatty acids are higher than recommended for the Australian and New Zealand populations (see below).
Are trans fatty acids identified on food labels?
Manufacturers are not required to declare TFAs on the label, although they can provide this information voluntarily. However, TFAs must be declared on a label if the manufacturer makes a nutrition content claim about cholesterol or saturated, trans, polyunsaturated, monounsaturated, omega-3, omega-6 or omega-9 fatty acids.
In January 2015 Ministers considered FSANZ's technical advice in response to a labelling review recommendation on TFAs. You can read more about that advice here.
What is happening in other countries about trans fatty acids?
In June 2015 the US Food and Drug Administration (US FDA) announced it had finalised its determination that partially hydrogenated oils (the primary source of manufactured TFAs) are no longer “generally recognised as safe”. The FDA has set a compliance period of three years. This will allow companies to either reformulate products without PHOs and/or petition the FDA to permit specific uses of PHOs. Following the compliance period, no PHOs can be added to human food unless they are otherwise approved by the FDA.
In Denmark, a law was implemented in 2003 that limited the amount of manufactured TFAs in foods to less than 2 per cent of the total fat content. The Danes consider a food to be free of TFAs if the TFA content in the finished food is less than 1 g per 100 g of total fat.
What can I do to reduce harmful fat in my diet?
While we are consuming levels of TFAs well below the WHO recommendation, we are still exceeding the recommendations in the Australian Dietary Guidelines and the New Zealand Food and Nutrition Guidelines that saturated and trans fatty acids combined contribute no more than 10 per cent of our daily energy intake. The main contribution to this is our high intake of saturated fatty acids.
According to the 2011/12 Australian Health Survey, the mean contribution of saturated and trans fatty acids to daily energy intake was 12% and 12.2% for males and females aged 19 years and above, respectively.
The most recent national nutrition survey for New Zealand adults, the 2008-09 Adult Nutrition Survey, also found high intakes of saturated fatty acids. The mean contribution of saturated fatty acids to daily energy intake was 13.1% for both males and females aged 15 years and above.
You can reduce your fat intake by following healthy eating guidelines: