Scientists have identified a deadly new rival to cholesterol, implicated in hundreds of thousands of deaths.

Scientists have identified a deadly new rival to cholesterol, implicated in hundreds of thousands of deaths.

They want the Government take action over homocysteine, a substance which occurs naturally in the blood after eating red or white meat. At high levels, it may cause serious damage to arteries.

Researchers at Hammersmith Hospital in west London are advocating a nationwide programme of vitamin supplements in breakfast cereals.

Homocysteine is a protein derivative also found in milk and eggs which is used to build body tissues. But in concentrated form it can lead to clots and, initial research shows, can damage blood vessels. Scientists say the vitamins help to counter the damage caused by homocysteine.

Hammersmith is one of only four centres in the world researching the link between homocysteine and cardiovascular disease.

Its scientists, funded by the British Heart Foundation, have discovered B vitamins such as B6 and B12 can reduce effects of homocysteine on the heart.

Heart disease is Britain's biggest killer, with 300,000 deaths a year. Until now, high levels of cholesterol in the blood, obesity and high blood pressure were seen as the major risk factors. A total of 1,500 patients from hospitals in west London is being studied and the results are expected in 2002. The work at Hammersmith is being led by Dr Jaspal S Kooner, consultant cardiologist, and Dr John Chambers, a lecturer in cardiology at Imperial College, London.

"We are convinced there is a link and the issue has been sidelined in the past," said Dr Kooner. "We are convinced our studies will prove positive. We have already shown the beneficial effects of B vitamins."

Much more work has been done on homocysteine in the US, where vitamins are routinely added to cereals. "It's a meat issue, although a balanced diet will give you a higher B vitamin content," added Dr Kooner.

Homocysteine was identified 25 years ago, yet all of the danger focus has been placed on cholesterol. The Department of Health is considering action after studying the Hammersmith Hospital study.