Is olive oil better for you?

We put this question to Bryan Lockwood, I'm a Professor of Pharmaceutical Science at the University of Manchester: Bryan - Olive oil has obviously got a long historic use in food and the olives have been eaten for a long time. By now of course, there's plenty of other dietary oils which we use as well. The recent increases in interest in health in westernised countries particularly those in the northern hemisphere has stimulated a vast amount of interest in research into the fat content of our diets. Linked to this, there's an increasing volume of epidemiological evidence which suggests that dairy and animal fats are less healthy, and this is now pretty widely understood in the medical fraternity and also, in the general public at large.

橄榄油的主要原因应该是beneficial for you is that the main lipid is oleic acid or oleic acid triglyceride, and it's about 3 quarters of that, and this is a particular type of fatty acid which is unsaturated. In fact, it's a mono unsaturated fatty acid which is accepted as being good for health. There's also some poly unsaturated fatty acids which of course have been widely discussed in the lay literature as well, again, highly beneficial for your health.

Both olive oils and seed oils in general have been showen to reduce low density lipoprotein lipid cholesterol which is abbreviated to LDL-C. This is commonly referred to as the bad type of cholesterol. Total cholesterol is also reduced. The combination of these two activities generally reduces a possibility of cholesterol depositing in the arteries.

Diana - So, olive oil is lower in saturated fat and the more olive oil there is in butter or margarine, the less dairy fat will be present, and therefore, less saturated fat. Our expert added that olive oil also contains high levels of anti-oxidants, and that these prevent free radicals from running around inside your body, damaging cells. But there's no conclusive evidence that anti-oxidants when taken via food actually make that much of a difference. But some people say, olive oil is less healthy when you fry it. Why might this be?

Bryan - Olive oil is quite interesting due to the high level of polyphenolics. You can actually see in the case of virgin oils and extra virgin oils, it's a green to dark green colour. This is judged to be of quality by the food sales people. If you happen to heat olive oil in a frying pan or a pan and get it up to about 93 degrees centigrade, it smokes, and this is obviously degradation of the oil. So, it's not beneficial to burn the olive oil itself, and in fact, this destroys its properties later on, so its anti-oxidant activity is dramatically decreased.

Diana - So there you are. Olive oil smokes slightly earlier than other oils, but if the clinical trials are anything to go by, it may be that losing a few anti-oxidants isn't a great loss.