Researchers have discovered a possible reason why green vegetables such as broccoli¹, cabbage and cauliflower are good for the heart.

研究人员发现为什么绿色蔬菜，像绿菜花、卷心菜、花椰菜对心脏有好处。

sprouts²" width="226" border="0" src="/upimg/090905/4_061538_1.jpg" />
Sulforapane is found in broccoli and brussel sprouts

Their work suggests a chemical found in the vegetables can boost a natural defence mechanism³ to protect arteries⁴ from disease.

The Imperial College London team hope their work could lead to new dietary treatments to prevent heart problems.

Details appear in Arteriosclerosis Thrombosis and Vascular⁵ Biology.

Much heart disease is caused by the build up of fatty plaques⁷（匾，饰板） in the arteries known as atherosclerosis（动脉硬化）.

However, arteries do not get clogged⁸ up with these plaques in a uniform way.

Bends and branches of blood vessels⁹ - where blood flow is disrupted and can be sluggish¹⁰（懒惰的，迟钝的） - are much more prone¹¹ to the build-up.

The latest study has shown that a protein that usually protects against plaque⁶ build up called Nrf2 is inactive in areas of arteries that are prone to disease.

However, it also found that treatment with a chemical found in green "brassica（芸苔）" vegetables such as broccoli can activate¹² Nrf2 in these disease-prone regions.

Lead researcher Dr Paul Evans said: "We found that the innermost（内心的，秘密的） layer of cells at branches and bends of arteries lack the active form of Nrf2, which may explain why they are prone to inflammation（发炎，红肿） and disease.

"Treatment with the natural compound sulforaphane reduced inflammation at the high-risk areas by 'switching on' Nrf2.

"Sulforaphane is found naturally in broccoli, so our next steps include testing whether simply eating broccoli, or other vegetables in their 'family', has the same protective effect.

"We also need to see if the compound can reduce the progression of disease in affected¹³ arteries."

Targeted approaches

Professor Peter Weissberg, medical director of the British Heart Foundation, which funded the research, said: "These fascinating findings provide a possible mechanism by which eating vegetables protects against heart disease.

"As well as adding evidence to support the importance of eating 'five-a-day', the biochemistry（生物化学） revealed in this research could lead to more targeted dietary or medical approaches to prevent or lessen¹⁴ disease that leads to heart attacks and strokes."

Using normal mice, and mice engineered to lack the Nrf2 protein, the research found that in straight sections of arteries Nrf2 was present in the endothelial（内皮的） 'lining¹⁵' cells.

Through its action on other proteins, it prevented the cells from becoming inflamed¹⁶, an early stage in the development of atherosclerosis.

In the lining cells of disease-prone sites - such as bending or branched arteries - Nrf2 was attached to a protein that made it inactive. This stifled¹⁷ its protective properties.

But the addition of sulforaphane re-activated Nrf2 in the disease-prone regions of the artery¹⁸, restoring the cells' ability to protect themselves from becoming inflamed.

The researchers believe that this will enable these artery regions to remain healthy for longer, or even reduce the progression of existing disease.