It’s official, trans fat in food is dangerous. If you were unaware of the risks of this shadowy food ingredient — trans what? — you should know about it now, since the National Institute for Health and Clinical Excellence (NICE), the body that advises the Government on how to improve the nation’s health, wants it to be banned.
Only a couple of decades after it was introduced into our food supply, this novel fat is now widely acknowledged to have increased our likelihood of developing heart disease, stroke, certain cancers and diabetes. And that’s just for starters; the full roll call of trans fat-related damage is yet to emerge.
NICE’s call may be a sign that Britain is belatedly waking up from a long slumber. Although this dangerous fat is a common component in many foods — from crackers and non-dairy ice cream through to fried chicken and croissants — it doesn’t have to be on the list of ingredients.
The absence of any attempt to protect the British public from the dangers of trans fat contrasts dramatically with the United States where, since 2006, any food containing more than 0.5 per cent has to be clearly labelled.
Public awareness of the risks is so high that cities such as New York and Philadelphia have outlawed it in restaurant food, while California has introduced a state-wide ban. “Trans fat-free zones” have sprung up all over the country as consumers stampede away from foods that contain it.
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Prominent food manufacturers have removed it from their products too.
Kraft, for instance, reformulated its popular Oreo biscuits to eliminate it. Other countries, such as Canada, Denmark and Switzerland, have introduced legislation to restrict it.
What is this substance? Man-made trans fat — which is diffferent from the harmless natural sort — first appeared in our food in the 1980s when public health orthodoxy, as it still does now, encouraged us to reduce our consumption of foods containing saturated fat, such as butter and fatty meat. Polyunsaturated fat, derived from plant sources, was recommended as a healthier alternative.
But this presented the food industry with a problem. Unlike saturated fat, which remains hard at room temperature without any processing, polyunsaturates must be hardened to stop them liquefying and going rancid. So the structure of the liquid oils is chemically altered by a bombardment of hydrogen, resulting in partially hydrogenated vegetable oil, a stable, saturate-free fat. This has allowed manufacturers to reinvent margarine — previously seen as the poor man’s answer to butter —as a health food.
The process also extended the shelf life of food; an extra benefit for the food industry. Only later did it emerge that this chemical process also resulted in the formation of trans fat, an artery-clogging fat that our bodies are not designed to digest; one that is more deadly than any natural saturated fat.
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The dangers were becoming apparent by the early 1990s, so margarine and spread manufacturers reformulated their products, ditching partially hydrogenated fat for interesterified fat. This is made by taking the “fractions” of the liquid oils, which are most solid at room temperature, and hardening them by rearranging the fat molecules under high temperature and pressure, using enzymes or acids as catalysts.
Because it does not form trans fats, sections of the food industry now present this second-generation hardened polyunsaturated fat as a healthy alternative to partially hydrogenated fat. Time will tell whether interesterified fat merits this profile but, given the food industry’s track record with high-tech fats, there are grounds for caution.
Meanwhile, although partially hydrogenated fat has more or less disappeared from the products in which it is most visible, such as spreads, it is still common in processed foods. That’s why many of the foods we eat daily still come with an unannounced side order of trans fat.
Paradoxically, as the scientific case implicating synthetic trans fats has hardened, so the case against naturally occurring saturated fat has begun to melt with a series of studies challenging the health establishment’s dogma that eating saturated fats in foods such as red meat, whole milk, cocoa butter and some nuts is bad for you. Most recently, a systematic review of scientific studies looking at links between dietary factors and heart disease, carried out by Canadian researchers, reported that the evidence does not support the putative link between saturated-fat consumption and heart disease.
For traditionalists who have always had a hunch that chemically altered fats would turn out to be bad news, the heightened focus on trans fats may reinforce the belief that it is better to stick with time-honoured foods with naturally occurring saturates than to embrace the latest techno-fat.
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What should you do? If you are worried about trans fat, you will need to become your own food detective and avoid foods that contain them. In stark contrast to the food authorities in the United States, the UK Food Standards Agency — which is responsible for ensuring the safety of the nation’s food supply — takes the view that legislation restricting trans fats would be “unlikely to deliver any significant health benefit” because UK trans fat intakes are “approximately half that of recommended levels”. Those who look to the Government to protect them from the damage caused by trans fat may have a long wait.
Spot the difference: a guide to fat
Trans fat
What is it?This is a potentially deadly fat formed when liquid oils are chemically hardened with hydrogen. It is widespread in many processed foods, such as popcorn and ice cream through to chips and cakes. One key category of food likely to contain trans fats is baked goods, such as biscuits and pastries. Unless they say “all butter”, or state that they are wholly made with an alternative fat (such as olive oil), then they could contain trans fat. The oil in which takeaway and restaurant food is fried is another likely source. Vegan alternatives to dairy products such as cream and cheese are also suspect.
Trans fat doesn’t have to be labelled. To avoid it, don’t buy any food that lists these ingredients “vegetable fat”, “shortening”, “margarine” or “partially hydrogenated vegetable oil/fat”.
Partially hydrogenated vegetable oil/fat
What is it? This has been chemically hardened using hydrogen. This process creates trans fat, which is to be avoided.
Interesterified fat
What is it? Fat which has been chemically hardened using enzymes or acids. Most margarines and spreads sold for baking and eating are now made in this way.
Interesterification does not form trans fat but the jury is still out on whether interesterified fat will prove any healthier in the long term than its dangerous hydrogenated predecessor.
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Saturated fat
What it is? Found naturally in animal foods such as milk, butter and meat and in some plant foods such as nuts and cocoa butter. For decades public health guidance has told us to shun it, but increasingly the evidence for the “saturated fat is bad for you” mantra is looking decidedly shaky. It is now widely agreed that saturated fat is less harmful than trans fat.
Polyunsaturated fat
What is it? A healthy fat that occurs naturally in many foods. The richest sources are seeds, nuts and oily fish.
Polyunsaturated fat falls into two main types: omega-3s and omega-6s. It is thought that the ideal balance of these fats for good health is three times more omega-3 than omega-6.
Monounsaturated fat
What is it? A healthy fat that is found naturally in a number of plant and animal foods. Good sources include avocado, olive oil, almonds, eggs and lamb.