Trans fatty acids are a term used for a specific type of hard fat. However, these trans fats or trans fatty acids are different from natural hard fats, such as those found in coconuts, in that they are formed when soft fats, so-called unsaturated fats, are converted in the food industry (the fat is hardened).
Trans fatty acids in food production
But if a large proportion of trans fat is in our diet due to the food industry, is it not easy to change this and reduce the consumption of trans fat? It's not that simple. Before the use of trans fats in the food industry, manufacturers used hard fats in their production, but the consumption of hard fats has a negative effect on human health. In their search for "healthier" options, manufacturers began to look at softer fats, but in many respects it is not suitable for food production as it craves sooner than hard fats and therefore shortens the shelf life of products made with soft fats. In an effort to improve the properties of the soft and "healthy" fat, manufacturers began to change its structure. The soft fat, usually vegetable fat, is partially hardened, ie made into a harder fat, and with this change it acquires certain properties which, among other things, manifest themselves in a longer shelf life. Financially, this change was therefore for the better for the companies, as a longer shelf life is a check that less food is thrown away.
Harmful of trans fatty acids
The Public Health Institute's general recommendations are to reduce the consumption of hard fats, and it does not matter whether they are trans fatty acids or saturated fats. Rather, you should choose fats that are soft, ie in liquid or soft form at room temperature. Consumption of soft fat that has been partially hardened, ie. trans fat, has increased sharply in recent decades. Consumption of foods containing trans fatty acids increases the risk of cardiovascular disease. The effect of consuming trans fatty acids can be seen in the fact that LDL cholesterol rises (bad cholesterol) and HDL cholesterol drops (good cholesterol). Consumption of foods containing trans fatty acids is therefore undesirable and in fact the less we consume trans fatty acids the better off we are with regard to the above risk factors and diseases. Food manufacturers, as well as others, are gradually realizing this danger, and the ban on the use of trans-fatty acids in New York City restaurants is the most obvious example of a change in thinking, although the merits of such consumption management can be disputed.
Consumption of trans fatty acids in Iceland
Icelanders generally consume too much fat and hard fat is too large a part of the country's total fat consumption. It is therefore not surprising that the consumption of trans fatty acids is disproportionately high among Icelandic consumers. According to the results of a survey conducted in 2002 on the national diet, the consumption of trans fatty acids averaged 3.5 g per day, but there were some groups, for example men aged 20-39, who consumed much more than 3.5 g per day. Consumption had then decreased by almost a third since 1990, mainly due to declining consumption of margarine and also because the composition of margarine had changed during this time. Despite the fact that Icelanders' consumption of trans fatty acids is on the right track, we still have a long way to go before we reach the upper limit set by the World Health Organization (WHO) as a limit for individual trans fatty acid consumption (2 g per day). The Public Health Institute is currently working on a new consumption study that will shed light on the situation among Icelanders as it is today. It should be noted that Denmark was the first to set rules regarding the maximum trans fatty acids in certain foods. In Denmark, edible oils, additives and margarine may not contain more than 2 g of trans fatty acids per 100 g of fat in the product. It has been decided to set similar rules in this country.
How can we avoid choosing foods that contain trans fatty acids?
Trans fatty acids can be found in many types of foods. Trans fats are likely to be found in margarine, frying fats, microwave popcorn, potato chips and other snacks, sweets, biscuits, cakes, wine breads, french fries and other deep-fried fast food as well as in other foods that have been overcooked.
Labeling of the amount of trans fatty acids on food packaging is significantly deficient. This is especially true for foods other than those from the United States, where strict rules on the labeling of trans fatty acids have been established. Consumers can, however, monitor the presence of trans fatty acids in foods by looking at the description of ingredients on the packaging. If the packaging says "hardened fat / vegetable fat", "partially hardened vegetable oil", "partially hydrogenated (vegetable) oil" or "partially hardened fat / oil", it is very likely that some trans fat can be found there. However, it is now possible to buy ingredients that contain saturated fats with a lot of saturated fatty acids but no trans fatty acids.
For further information, please contact Ólafur Reykdal, olafur.reykdal@matis.is, and Steinar B. Aðalbjörnsson, steinar.b.adalbjornsson@matis.is.