Eating one portion of fish a day might help to counteract the damaging effects of smoking on the arteries.

Eating one portion of fish a day might help to counteract the damaging effects of smoking on the arteries.

Researchers who gave supplements of taurine, an amino acid present in oily and white fish, to 30 smokers and non-smokers found it reduced the hardening of the arteries caused by smoking.

The condition, known as endothelial dysfunction, means the arteries are not able to dilate as they should, leading to atherosclerosis, the narrowing of the arteries that increases the risk of heart attacks.

Scientists from Beaumont hospital in Dublin tied tourniquets round the arms of smokers and non-smokers and measured the change in blood vessel size by ultrasound. The results showed dilation of the blood vessels in non-smokers but not in the smokers. But when the smokers were given a dose of 1.5 grams of taurine a day, the amount found in one serving of fish, the difference between the groups disappeared.

Professor David Bouchier-Hayes, who led the research published in Circulation, the journal of the American Heart Association, said: "When blood vessels are exposed to cigar-ette smoke it causes the vessels to behave like a rigid pipe rather than a flexible tube, so the vessels can't dilate in response to increased blood flow.

"We are not trying to find a therapeutic treatment for smoking because we believe the best therapy for smokers is to stop smoking. None the less, smokers provide a good clinical model for treatment of endothelial dysfunction."

The researchers found that vitamin C had a similar though less pronounced effect on the blood vessels of smokers. A separate study showed a drug used to treat gout, allopurinol, also greatly improved smokers' endothelial function.

Clive Bates, director of anti-smoking group Ash, said: "The best way of looking at it is as something that could have very important consequences for the treatment of heart disease, but shouldn't be seen as a magic pill that somehow makes smoking safe. No one in their right mind would think that."

¿ Hormone replacement therapy can cut rates of diabetes by up to 35 per cent in women with heart disease, according to a study on 2,000 heart patients reported in the Annals of Internal Medicine.