Something fishy with Fish Oils?: Part 1

Before beginning this post we would like to thank everyone who has written to us with comments on both the blogs and the website. It is wonderful to receive such positive feedback and words of encouragement. And yes, we do intend to keep going as we’ve begun.

For many years, my research interest was in fats and oils. While both challenging and academically interesting, it wasn’t a riveting dinner party conversation! Later, this interest took me in other directions, specifically the study of genetic diseases involving fats. Just after finishing my Ph.D at London University, I was working in a field that really was a dinner party conversation piece – the fats in spermatozoa, the male sex cells in semen. (Alf must go to different dinner parties than I do! – Stephen).

Most people would be surprised that sperm are loaded with some quite unusual fats. One day I returned from a long lunch to discover I had forgotten to turn off the analytical machine I was using at the time (a gas chromatograph for those who want to know). I was amazed to find a huge unknown peak on the trace. I initially thought this peak must have been a contaminant – this is what scientists often think when they get something unexpected. However it soon became clear it wasn’t a contaminant as the huge peak was there every time I ran the sample. I eventually showed the “contaminant” was a fat called DHA, short for docosahexaenoic acid or 22:6, n-3. It turned out this DHA was by far the major fat in sperm. At the time, no one knew why sperm had such high levels of this fat. We still do not know.

We now know DHA is not just in sperm but is present in many of our organs. It is particularly rich in two parts of the body: The retina in our eyes and our brain. We still don’t know why our brain and retina need such large amounts of DHA but we do know there must be a very good reason. We also know that fish contain very high levels of DHA and another fat, EPA, short for eicosapentaenoic acid or 20:5, n-3. Chemists refer to these fish fats as “Omega-3 fats” to distinguish them from the “Omega-6 fats” which are found in animal fats and vegetable oils. Under normal circumstances, our bodies can make both EPA and DHA, provided we have a normal healthy diet that contains the necessary precursors and raw materials.

Omega-3 fats are often called the “good” fats in the popular press and have become big business. They seem to be almost everywhere. They are present in aquaculture, functional foods and supplements and are added to a whole host of foods including bread, butter, margarine and infant formulas to name just a few. And it seems almost everyone is taking fish oil supplements. With my long background in fats and a naturally questioning nature, I began to wonder about some of the claims being made for fish oils on the internet and in the popular press. Read the rest of this entry »

Michael Douglas and conflicting messages

The other night I was watching David Letterman interview Michael Douglas about his diagnosis for throat cancer. During the interview, Michael Douglas admitted he was a drinker and that his cancer was a type caused by alcohol. There is no question that alcohol does increase the risk of various cancers, including throat and esophageal cancers: There are certainly enough reports in the medical and scientific literature saying so. However, whether anyone can categorically state that Michael Douglas’s cancer was due to alcohol alone is doubtful because cancer is a complex disease with many contributing factors. For example, Michael Douglas is also a smoker. Smoking itself is a cancer risk factor and the combination of smoking and alcohol increases the risk even further. What was particularly interesting was when the reporter commented on the level of alcohol consumption required to cause cancer. By the end of the interview the audience may well have thought even moderate drinking would increase their risk of cancer. And it didn’t matter what form the alcohol was in either: Beer, wine, whisky or whatever else. As long as it had alcohol in it, it was a risk. The final part of the story was devoted to speculation on how alcohol may increase the risk of cancer. The chemical acetaldehyde was suggested as the likely culprit. Acetaldehyde is a known carcinogen and is formed from alcohol in the body. Read the rest of this entry »