Fish Oil Prevents Stroke
April 25, 2005
Many believe that fish oil protects against stroke, but French researchers have now discovered how this works. Fish oil helps the brain to better cope with a reduced blood supply.
Fish oil must be close to being the world’s best medicine. If you get fatty fish two to three times a week, you protect yourself against suddenly suffering cardiac arrest. The risk is halved. But also the risk of a blood clot in the brain – by far the most frequent cause of so-called cerebral hemorrhage – and thus suffering a stroke, decreases. According to the largest, but not final study, so far, it is reduced by 40%.
It is consistent with animal research. Mice that are artificially exposed to a blood clot in the brain get less extensive brain damage if they in advance are fed with fish oil. Now French scientists have proven a mechanism that might explain this phenomenon.
Scientists from France’s National Science Research Center, CNRS, are behind the discovery. They have shown that the protection of the brain cells is due to the effect of fish oil on the cell’s potassium channels.
The mineral potassium is the dominant one inside the cells, while sodium (found in table salt) is the dominant one outside. Potassium enters and exits the cells via specially designed channels, which can be more or less open. When they are open, potassium can flow out of the cell, and the cell relaxes. When they are closed, the opposite happens.
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 susceptible to oxygen deprivation. The French showed that if the channels are partially disabled by genetic manipulation, fish oil does not protect the mice when they suffer a brain hemorrhage. Even small seizures lead to death. At the same time, mice with this genetic defect suffer brain hemorrhages much more often than healthy mice.
In other words, it is the potassium channels that protect the nerve cells, if they are kept open with fish oil.
There are also prescription medications that open the potassium channels. One of them, Angicor ®, acts on the blood vessels and is used to treat angina pectoris (heart attack). The opening of the potassium channels causes the coronary arteries of the heart to relax and widen, allowing blood to flow more easily. The heart receives blood and oxygen. A similar effect of fish oil on the blood vessels of the brain could also explain the French finding.
Whether fish oil helps against angina pectoris, however, is unknown. Some trials have shown it, others have not. But the French believe that their discovery supports a suspicion that many have: that fish oil, in addition to protecting against cerebral hemorrhage, also counteracts such widespread diseases as epilepsy and depression.
By: Vitality Council
References:
1. Heurteaux, C et al. TREK-1, a K(+) channel involved inneuroprotection and generaql anesthesia. EMBO J. 2004, E-pub 2004, June 03.
2. Lauritzen, I et al. Polyunsaturated fatty acids are potent neuroprotectors. EMBO J 2000;19:1784-93.
3. Ka He et al. Fish consumption and risk of stroke in men. JAMA 2002;288:3130-6.
4. 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.
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