Why are we so worried about trans fats - and are the other options any better for us? Fiona Tyrrellreports
MORE REVILED than E numbers and giving tobacco a run for its money in the villain stakes, artery-clogging trans fats have earned a reputation as the next great public health menace.
New research, however, indicates that the level of trans fats in pre-packaged foods on the Irish market is much lower than anticipated.
Conversely, the study reveals high levels of saturated fats, suggesting that while the spotlight of public debate has focused on trans fats, high levels of saturated fats have been ignored.
Responding to growing public concern about trans fats, the Food Safety Authority of Ireland (FSAI) conducted a fat-profile survey of 100 common pre-packaged foods on Irish supermarket shelves. The range of products surveyed was wide, including sausages, breaded fish, biscuits, mince pies, dried pasta meals, frozen pizzas, curry sauce and dried soups.
The results make for some interesting reading and have taken many in the industry by surprise.
Overall, the survey found that levels of trans fats are low, with 57 per cent of products surveyed having no trans fats and 23 per cent containing low levels (less than 2 per cent of total fat being trans fats).
Levels of saturated fats, however, were a different story. Some 34 per cent of all the products reviewed contained more than half of their fat in the form of saturated fats. This, according to the FSAI, is of "public health concern".
Some products sampled, such as cereal and milk bars, had saturated fat concentrations exceeding 84 per cent of their total fat content. Based on an average portion size of 20g, this represents about 6 per cent of the guideline daily amount for an adult male and 8 per cent for a female.
Other serious offenders in the saturated fat stakes were a tortilla product, a wafer biscuit and a cheese and bread stick snack.
The low trans fats findings, according to the FSAI, confirm that the actions of the food industry have reduced the amounts of trans fats in foods. The high saturated fats results, however, have prompted the FSAI to warn the food industry against replacing trans fats with saturated fats.
While not the focus of the FSAI study, the fat-profile findings raises questions about the food processing industry. In the rush to get rid of nasty trans fats, have saturated fats been reintroduced to convenience foods?
There is no firm evidence that the food sector is replacing trans fats with saturated fats, but Dr Wayne Anderson from the FSAI expresses concern at the fact that many products surveyed had low trans fat content but high saturated fat levels.
The recent focus on previously unknown trans fats, according to Anderson, is a classic example of how we tend to focus more on new unfamiliar risks (trans fats), ignoring potentially greater but more familiar risks (saturated fats).
In a way, saturated fats have become the "white elephant in the room", he says.
On a gram-for-gram basis, trans fats are worse for heart health than saturated fats - however, saturated fats are more likely to contribute to heart disease because our intake of this type of fat is substantially higher, he explains.
Trans fats originally made their way into our diet as a "healthy" alternative to saturated fats in the 1960s. Industrial trans fats are made when liquid vegetable oils are mixed with hydrogen and heated to a high temperature. The result is a solid fat that looks and, more importantly, tastes, like a saturated fat.
Trans fats are cheap to make and significantly extend the shelf life of a food product, making them a big hit with the food-processing sector.
Since then they have worked their way into the ingredient list of many supermarket shelf food stuffs - cakes, biscuits, margarine, ready meals and dried food. Industrial trans fats can also be found in the cooking oil used in fast food restaurants.
Then, in around 1990, the shine went off trans fats - a number of studies indicated that trans fats contributed to heart disease. Like saturated fats, they raise bad (LDL) cholesterol, but, unlike saturated fats, trans fats also reduce the level of good (HDL) cholesterol.
Once a largely ignored ingredient on pre-packaged foods, trans fat fast became the bête noire of the food industry.
Retailers removed it from their ingredient list and fast-food chains tripped over themselves to get on the anti-trans fat bandwagon.
KFC, McDonald's, Marks Spencer and Kellogg's are among food producers that have reduced or removed trans fats from their products.
In June 2003 Denmark became the first European country to introduce a ban on products which contained more than 2 per cent of their total fat content in the form of trans fats.
Two years later the EU commission urged Denmark to remove the ban, on the grounds that it was causing a barrier to trade.
The commission later dropped its infringement proceedings against Denmark.
In 2005, Canada became the first country to regulate the mandatory labelling of trans fats on pre-packaged foods and the United States introduced a mandatory declaration of trans fats in foods containing more than 0.5g of trans fat per serving.
A number of new technologies have been developed which have the ability to minimise or remove industrial trans fats from foods.
The FSAI has called on the food industry to adopt such creative solutions to reformulate food without trans fats.
The bid to reduce trans fats "should not include the replacement of trans fats with saturated fats, even in the short term, because this is not a sustainable solution for the improvement of dietary health", the FSAI warns.
Responding to the survey, Maureen Mulvihill of the Irish Heart Foundation says it is positive to see that over half of the foods surveyed had no trans fats. The number of products, however, with high saturated fats was a "cause for concern", she says.
We should be aiming for as little trans fats in our food as possible, according to Mulvihill.
Many foods processors have removed trans fats from margarine and dairy spreads, she says. One of the main sources of trans fats is now likely to be the fast food sector, which has much work to do, she adds.
While low levels of trans fat are defined as products which have less than 2 per cent of fats in the form of trans fats, these should be regarded as maximum levels, she says.
Information about food goodness is always evolving, but what does not change are the simple facts about eating a healthy diet based on the food pyramid, she says.
Trans fats are also a natural component of animal fats and are present in meat, milk and diary products.
Although recent studies have suggested that these natural trans fats are not as bad for heart health as other trans fats, the "jury is still out", according to Anderson.
Unlike the foods where industrial trans fats are found, these foods make an important nutritional contribution to diet that outweighs their moderate trans fat content.