A third of all British women admit to drinking a moderate amount of alcohol or more each day. Until now, consuming up to two units a day was considered to have certain health benefits, helping to prevent heart disease and cut the risk of strokes.

However,the latest study by American scientists has found that the same quantity of alcohol can rapidly increase the risk of breast cancer, a disease that kills 12,400 women a year in Britain alone.

Experts last night described the research as worrying. Ed Yong, of Cancer Research UK, said, "We have known for some time that alcohol increases the risk of breast cancer.

"But this research suggests it can also promote the growth of existing tumours. The results reinforce the message that women can reduce their risk of breast cancer by cutting down on how much they drink."

In the study, researchers at the University of Mississippi Medical Center gave female mice the human equivalent of two drinks a day for four weeks, while a control group of mice was given no alcohol at all. In the second week, mouse breast cancer cells were injected into each animal's mammary glands. few weeks later, the tumours in the alcohol-fed mice weighed 1.4g on average, almost twice the size of tumours in the control group.

The researchers believe alcohol resulted in the larger tumours due to an increased growth in blood vessels. Without blood vessels to feed the tumour with oxygen and nutrients, it would die. But when alcohol is consumed, cells go into overdrive to get rid of the toxins, sending out a hormone called VEGF that stimulates the growth of blood vessels.

The alcohol-fed mice had raised levels of VEGF as well as more blood vessels than the other mice.

Jian-Wei Gu, who led the research, said, "This is the first study to use an animal model that accurately mimics human breast cancer.

"Normal people produce cancer cells every day but, at the beginning, the cancer doesn't have blood vessels, so it's easier for the immune system to fend them off. Once the cancerous cells acquire a blood vessel lifeline, fostered by alcohol, the tumour growth takes off."

More than 42,000 women in Britain are diagnosed with breast cancer every year. The figures mean that about one in nine British women will now develop breast cancer at some point in their lives.

Drinking one unit of alcohol a day increases a woman's risk of breast cancer by about 6%, claims Breakthrough Breast Cancer.

From the May 9, 2007, Prepared Foods e-Flash