Friday, 27 November 2009
Why do I want to talk about trans fats? Recently I caught a repeat on our new digital tv screens of a program hosted by Top Gear’s Richard Hammond. He wondered wether we should be worried about trans fats and at one point went into a sewer (in protective clothing) and the stench was apparently MUCH worse than he was expecting. We were shown huge pile of fat from fast food outlets and restaurants which had taken up residence down there. Not what I expected, they looked like giant piles of ash! The outcome of this show (yes they had a chat to a professor of nutrition), was that if we are eating 2 or 3 takeaways a week then we are putting our health at serious risk. This was in 2006 and I think people maybe in need of a reminder of exactly what trans fats are and which foods contain them and so to avoid. Hence this post.
Everyone has heard of them and knows that they are very bad for us, but what exactly are they? Any organic chemist or good food nutritionist ought to be able to tell you. So here is a quick chemistry lesson.
At room temperature, oils are liquids and fats are solids. The reason has to do with their chemical structure. The main backbone of all fats is a long chain of carbon atoms. In nature, fats contain some double bonds, these are what are known as unsaturated fats.
It is at these double bonds that addition of hydrogen takes place.The double bonds are broken during such reactions and the end product consists of a new single bond. This is now a saturated molecule/fat. There are 2 ways in which these new hydrogen atoms can add to the molecule which means there are 2 types of resulting
fats. Look at the carbons marked with a red asterisk. Both hydrogen atoms are bonded on the same side of the carbon atoms. This is known as a ‘Cis’ fat. This occurs in most cases and causes the chain to be bendy. Cis fats occur naturally. However during the manufacturing process, bombarding the chains with hydrogen results in the 2 new hydrogen atoms being attached on opposite sides, i..e a trans fat.
This gives a more solid structure. As a result trans fats are found in large amounts in dairy products and meats. Health implications of trans fats are cancer, diabetes, heart attacks, strokes, reduced sex drive and just generally not feeling great.
Its best to eat a sensible diet making sure it contains enough fruit and vegetables and using vegetable oils rather than solid butter. Be sure to ask your local chip shop etc if they use hydrogenated oils. Lets hope they say no and they are telling the truth.