Sunday, February 19, 2006

Fish oil

[The doctor neither sells fish oil nor has an interest in fish oil companies]

One of the things I was taught in Preventive Health class was that Eskimos, although mainly carnivorous, have a very low incidence of CAD, just as Japanese in Japan. However, the Japanese in California have incidence of CAD that is almost similiar to white Americans. The Japanese in Hawaii have an incidence of CAD almost in between that of Japanese in Japan and Japanese in California. This important epidermiological observation gave rise to the principle that it must be the fish diet that Eskimos and Japanese have in common.

We now know that fish oils contain n3-polyunsaturated fatty acid (n3-PUFA), the important fish oil component giving the cardiovascular benefit. What is lacking is a large randomised control trial giving us conclusive evidence of this. Obviously these trials will never be as no corporation will spend the large amount of money to do this, as fish oil is non-patentable, so they cannot recover their expenditure.

There are smaller studies which conclude that in addition to primary prevention of CAD in Eskimos and Japanese, fish oil has also reduces the incidence of cardiac deaths, especially sudden cardiac death, following heart attacks. The risk of sudden cardiac death may be reduce as much as 45%. Besides that, fish oil also lowers plasma triglycerides and reduces the coagubility of blood, probably by lowering serum fibrinogen. There is some evidence that the n3-PUFA is incorporated into an atherogenic plaque, stabilising the plaque. Maybe that is why fish oils have been shown to lessen angina pectoris.

If you wih to take fish oil tablets, please know that you may have to take 1-2 grams daily, or take enough to smell fishy. Always be aware that there is increasing concern about the dangers of heavy metal contamination in fish oil. For those who would like to take fish, please note that different fishes have different concerntration of n3-PUFA. The deeper the sea, the colder the sea, the greater concentration of n3-PUFA in the fishes.

Basically, fish oils are good for CAD and sudden cardiac death prevention.. This is one nuticeutical agent with well proven cardiovascular benefits.

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