Food labels should list trans fats as well as cholesterol and saturated fat to help reduce coronary heart disease, say researchers from the University of Oxford in this week's BMJ.

Trans fats (also known as trans fatty acids) are solid fats found in margarines, biscuits, cakes, and fast food. Scientists think that our bodies deal with these fats in the same way as saturated fats.

Both saturated fats and trans fats increase the amount of low density lipoprotein (LDL) or 'bad cholesterol' in the blood and reduce the amount of high density lipoprotein (HDL) or 'good cholesterol.' People with high levels of LDL cholesterol tend to have a higher risk of getting heart disease, while people with high levels of HDL cholesterol tend to have a lower risk.

A recent analysis of all the evidence recommended that people should reduce or stop their dietary intake of trans fatty acids to minimise the related risk of coronary heart disease.

This analysis found a 2% increase in the energy intake from trans fatty acids was associated with a 23% increase in the occurrence of coronary heart disease. In fact, the authors noted that the harmful effects of trans fatty acids were seen even when intake was really low, only 3% of total daily energy intake (20-60 calories), about 2-7 g for a person consuming 2000 calories per day.

Legislation introduced in Denmark in 2004 mandated that all oils and fats used in locally made or imported foods must contain less than 2% industrially produced trans fatty acids. This virtually eliminated trans fatty acids and had no effect on quality, cost, or availability of foods.

And in January 2006 the US Food and Drug Administration mandated that all food manufacturers provide the content of trans fatty acids and cholesterol in addition to saturated fat on nutrition labels for all manufactured foods, write the authors.

The UK Food Standards Agency is currently pressing for revision of the European directive that governs the content and format of nutrition labels on foods marketed in the United Kingdom and other European countries, so that these fats are labelled.

They believe that mandatory addition of the content of saturated fat and trans fatty acids to nutrition labels would enable consumers to make healthier food choices that could lower LDL concentrations and reduce the risk of coronary heart disease and other vascular events.