What do you know about industrially produced trans fatty acids? Unless you are actually a nutritionist or a doctor, the answer is most likely to be: nothing at all. And why should you? One survey a few years ago found that of the sample asked, 15 per cent thought trans fats were good for your love life.
Trans fats are a closely guarded secret. The food production and catering industries want to keep it that way. A handful of outlets have voluntarily started to cut back on their usage under consumer pressure, but there is no law against them.
Trans fats are a lethal side effect of boiling vegetable oil. Why boil vegetable oil? That all goes back to a pharmacist called Wilhelm Norman in 1903. Mr Norman was trying to find a way of making a substitution for tallow, which was very expensive at the time. Mr Norman discovered that if he boiled cotton seed oil up to 260 degrees Centigrade in the presence of a catalyst such as nickel, that when it cooled, it went hard. He had produced cheap candle wax by 'hydrogenating vegetable oil'. The thick, grayish-white slabs produced were great candles but Mr Norman did not expect human beings eating them.
Food giant, Proctor & Gamble, saw the potential and bought the patent from Mr Norman. They were soon producing Crisco in America, a hard vegetable fat that was great for baking and had a long shelf life. Along came a whole series of Crisco cookery books for Japanese, Jewish or Philippine households. Titles included: A Cookery course in 13 Chapters; 24 Pies Men Like; and Crisco Recipes for the Jewish Housewife. That Crisco contained no animal fat made it ideal for vegetarian, Kosher and Halal households.
But there was a problem: this industrial processing of vegetable oil into hydrogenated fat (HVO or PHVO) turned out to be killing people. It was not really until a big clinical trial, The Nurses' Health Study, which ran for about 10 years in the 1970s and 1980s that the damage really surfaced.
By carefully detailing just what kinds of fat were consumed, the researchers identified this hydrogenated or partially hydrogenated vegetable oil as the queen of fast food fats that was more than a killer than planned fats. In fact they discovered that you would need to increase your intake of saturates by about 900 per cent to get the same impact as you would from the same amount of trans fat. Just small amounts of trans fat - say two grams a day - increases your risk of heart disease by 23 per cent.
There's no use looking for cartons of trans fat to be avoided on the supermarket shop. What you need to find is hydrogenated-anything, but that will be on the ingredients panel, very possibly in a text size so small that unless you've brought your magnifying glass, you'll be in trouble. On top of that, because in-store bakery food does not need to declare its ingredients, you may still be innocently purchasing dangerous commercially baked produce.
So certainly the European Foods Standards Agency would ban it immediately? No. It was far too useful in the catering trade. It gives great 'mouth feel'- the sort of thing you get with a nice sticky, moist donut or a Danish pastry. It lengthens shelf life too. One man lobbying against trans fats in America appears on television with a cup cake made more than 20 years ago. It still looks perfect and has retained the soft springiness associated with such confections.
Like so many of the dangerous substances we consume, trans fats appear in everything from stock cubes to sweets, children's cereals to vitamin tablets, Danish pastries to donuts, deep fried foods in restaurants, lunchtime snacks like sausage rolls and other produce from takeaways everywhere. They were in lots of the Easter eggs we gorged on a few weeks ago such as the Quality Street ones and they are even in some of the so-called 'energy' or 'health' bars on the supermarket shelves.
It is ironic that so many Danish pastries contain trans fat because Denmark was the first country to ban them in 2000. Nowhere there can be hydrogenated vegetable oil used and that includes within the catering and restaurant industries as well as the food producers. On 1 April this year, Switzerland followed Denmark and introduced similar legislation. Here in the UK and most of the rest of Europe, we continue to gorge our way through mountains of dangerous products.
When I came to write Trans Fat: The Time Bomb in Your Food (Souvenir Press £ 8.99), it was this deception that really annoyed me. How dare the Food Standards Agency, our elected politicians, the consumer outlets and the catering and restaurant industries do not tell us that we are eating candle wax.
All of them have known full well about how trans fats are associated not only with a five-fold increase in heart disease but also with Type 2 diabetes, some cancers, infertility, inflammatory diseases, obesity and insulin resistance.
Eight of the big supermarkets said in January 2007 that they would remove all trans fats from their 'own brand' ranges within the year. Some managed it. Others did not. There's nothing the law can do because this was a voluntary agreement. Besides, how much of what you buy in the supermarket is 'own brand' produce? If you shop at Sainsbury or Tesco say, then it's probably no more than 10 per cent.
Professor Steen Stender is the cardiologist in Denmark who became the force behind the decision to ban trans fats there. He says: "Between the introduction of the ban in 2000 and 2005, we saw heart disease rates in this country decline by 20 per cent. What more proof does the EU need before it dispenses with ineffective food labeling ideas and voluntary codes and introduces a level playing field for the food industry throughout the EU where no trans fats are used anywhere? "