This next post from Dr Geoff is the second on the topic of Fish Oils and Omega-3 Fatty Acids:
We should all know by now that eating too much fat or oil is bad for us and increases our risk of obesity, diabetes, heart disease and some cancers. Disturbing posters produced by the British Heart Foundation are trying to dramatically bring this home to us by showing a child drinking a bottle of vegetable oil. Their message is that 60% of children eat a packet of crisps a day which is equivalent to drinking 5 litres of oil a year! Yet despite these strong anti-fat and anti-oil messages we are being encouraged to eat two portions of oil fish each week and millions of us take daily supplements of fish oil or cod liver oil – a 10ml daily dose of cod liver oil is equivalent to drinking 3.5 litres of oil in a year! Fish oil, vegetable oil and solid animal fat all contain the same number of calories so are equally fattening but vegetable oils and fish oils also contain essential fatty acids that we must eat in small amounts to prevent symptoms of deficiency.
There are two classes of essential fatty acids, the so-called omega-6 group found large amounts in vegetable oils and the omega-3 group which are present in large amounts in fish oils. The largest members of these two classes of essential fatty acids have important functions in cell structure and they are also used to make substances called prostaglandins that regulate blood clotting, inflammation and many other processes in the body. We get plenty of all the omega-6 fatty acids (probably too much) but the only major source of the larger omega-3 fatty acids in the diet is from fish oil and our large intakes of omega-6 fatty acids limits our ability to convert smaller omega-3 fatty acids from other foods into these larger ones (known as EPA and DHA).
There have been several recent reports in the press which suggest that fish oil supplements may improve behaviour, increase attention span and improve school results in children. At least one education authority (Durham) is proposing to offer fish oil supplements to all children in its area. There are clinical trials which suggest that very high doses of fish oils may improve these things in children who have recognised behaviour, hyperactivity and attention disorders. To my knowledge there are no proper scientific studies showing that more moderate doses of fish oils have similar benefits in other children.
Check back for more articles on this topic!