Fish Oils

Cod Liver Oil has been used as a medicine for centuries although its clinical use did not begin until the mid 17th century when it was given to people suffering with bone disease and rheumatism. At that time no-one knew why it worked.

A Time-Honoured Remedy

Research continued and cod liver oil was found to contain many nutrients that were not easily obtained from non-marine sources. Cod liver oil is a rich source of fat-soluble vitamins, A, D and E and also contains polyunsaturated fatty acids (EPA and DHA) which have essential roles in the body's metabolism.

In 1970, two Danish doctors discovered that Eskimos in Grenland had a low incidence of coronary heart disease, associated with eating large amounts of fatty fish and seafoods. Further tests showed that EPA (eicosapentanoic acid) is contained in far greater quantities in the blood lipids of Eskimos, as is DHA (docohexaenoic acid). This is needed in high proportions in the grey matter of the brain, the nerve tissue and the retina of the eye to ensure healthy functioning of these organs.

So perhaps the "old wive's tale" of fish being good for the brain is not so far fetched!

Other items of interest

Researchers at the University of London have shown that fish oils can lower the risk of heart disease and reduce cholesterol levels and it has also been indicated that EPA can help with arthritis and rheumatism.

A Dutch researcher carried out surveys in more than 16 different countries to measure fish intake relative to heart disease frequency. His results showed that the groups eating no fish have a 10 times greater risk of heart disease than groups like the Japanese or the Eskimos who eat a great deal of fish.

More importantly, it is also shown that eating a limited amount of fish reduces the risk significantly so that changing the diet from eating no fish to eating 50g a day will reduce the risk by half. (One tsp of cod liver oil is equivalent to 50g fish.)

There is also good news for those who have had heart trouble. A study carried out by the Medical Research Council gives direct evidence that increasing the fish oil intake can reduce the risk of death from heart disease where one heart attack has already been suffered. One group advised to take 6 cod liver oil capsules a day (or eat fatty fish at least twice a week) had a 35% better survival rate.

Could fish oils calm us all down?

The intriguing possibility that eating more fish or supplementing the diet with fish oil capsules could calm us down has been raised by research published in the Lancet.

The idea comes as a result of a study suggesting that people with a high level of a certain type of fat in their blood tend to be more aggressive. Researchers in Edinburgh took samples from 1,500 randomly selected middle aged men and women. These were then measured for the different types of fat and the subjects' personality profiles examined, assessing them for factors such as hostility and the extent to which they looked down on, or tended to dominate, other people.

After taking into account factors such as smoking and drinking habits, it was found that those with the most aggressive attitudes had higher levels of the triglyceride type of fat in their blood. The connection with fish lies in the well-established fact that eating more of the oil found in fish lowers the level of triglyceride due to its Omega-3 polyunsaturates content.

"A reduction in aggressiveness may be one more of the factors contributing to the explanation of how eating more oil-rich fish reduces heart disease risk" comments Fish Foundation chief executive, Dr Ray Rice.

Daily Dose

During the period from 1930 to 1950, the Government provided cod liver oil through the NHS as a vitamin A and D supplement to ensure healthy growth and bone formation in children and it was not until 1971 that the free distribution of cod liver oil was dropped at health clinics because of decreased demand.

For many of us, the daily dose of cod liver oil is a never to be forgotten experience as it tastes so unpleasant. Cod liver oil remains the subject of very extensive research and the good news is that much as been done to make it far more palatable.