Fish oil makes the brain less sensitive to reduced blood flow.
Fish oil must come close to being the best medicine in the world. If you eat fatty fish 2 - 3 times a week, you will, among other things, be protected from suddenly falling to the ground with a heart attack. However, also the risk of cerebral thrombosis - the far most common cause of cerebral haemmorhage - and thereby the risk of falling down with a stroke will be reduced. According to the largest (but not yet final) study so far the risk is reduced by 40%.
This corresponds with animal studies. In one study, mice who had been artificially afflicted by a cerebral blood clot suffered much less extensive brain damage if they had been given fish oil some time in advance. Now, French researchers have demonstrated a mechanism that might explain this phenomenon.
Researchers from the French National Centre of Scientific Research, CNRS, are behind the discovery. They have demonstrated that the protection of the brain cells are caused by the effect of fish oil on the cells' potassium channels.
The mineral potassium is the dominating mineral in the interior of the cells while sodium (which is also present in normal cooking salt) is the dominating mineral outside/between the cells. Potassium enters and leaves the cells by specific channels that can be more or less open. When they are open, potassium can float out of the cell and the cell will relax. When they are closed, the opposite will happen.
Relaxed blood vessels
The N-3 fatty acids in fish oil open the potassium channels and may thereby make the cells more relaxed - at least less sensitive to oxygen deficiency. The French researchers demonstrated that if these channels were partly eliminated by means of genetical engineering, the fish oil would not be able to protect the mice when they were afflicted by cerebral haemmorhage: Even small attacks would result in death. At the same time, mice with this genetic defect would suffer cerebral haemmorhage far more often than normal mice.
In other words, the potassium channels are the ones that protect the nerve cells - that is, if they are being kept open by fish oil.
Prescription medicine also exists that opens up the potassium channels. One of them is Angicor®; it also has an effect on the blood vessels and is used against angina pectoris (cardiac pain). The opening of the potassium channels makes the coronary vessels relax and dilate which in turn makes the blood flow more easily. The heart is supplied with blood and oxygen. A similar effect of fish oil on the cerebral blood vessels might also explain the French findings.
Whether fish oil is effective against angina pectoris, however, is unclear. Some studies have indicated this; others have not. The French researchers believe that their discovery substantiates a suspicion supported by many: That fish oil, besides being able to protect against cerebral haemorrhage, also counteracts common diseases such as epilepsy and depression.
- Heurteaux C et al. TREK-1, a K(+) channel involved inneuroprotection and generaql anesthesia. EMBO J. 2004, E-pub 2004, June 03.
- Lauritzen I et al. Polyunsaturated fatty acids are potent neuroprotectors. EMBO J 2000;19:1784-93.
- Ka He et al. Fish consumption and risk of stroke in men. JAMA 2002;288:3130-6.
- Salachas, A., et al. Effects of low-dose fish oil concentrate on angina, exercise tolerance time, serum triglycerides, and platelet function. Angiology, Vol. 45, December 1994, pp. 1023-31.