Breastfeeding cuts a woman's risk of breast cancer by up to a fifth, a major study has found.

Thousands of cases could be avoided if more mothers persevered feeding their babies breast milk for six months, experts say.

Research involving almost 37,000 women found those who had breastfed were 10 per cent less likely to get the disease.

Research has found that women who had breastfed were 10 per cent less likely to get breast cancer and 20 per cent less likely to develop one of the worst forms of the disease, known as triple negative

And they were 20 per cent less likely to develop one of the worst forms of breast cancer, known as triple negative.

In Britain, just 23 per cent of women breastfeed for six months, often giving their babies some formula milk as well. But the World Health Organisation recommends breastfeeding alone – with no formula – for six months.

US researchers at two charities and Washington University in St Louis, Missouri, analysed 27 studies covering 36,881 women.

Those who had breastfed for any length of time reduced their risk of breast cancer by 10 per cent.

...AND IT HELPED SCARLETT LOSE BABY WEIGHT Scarlett Johansson (pictured) claims breastfeeding helped her get her figure back after birth Scarlett Johansson claims she got her figure back after giving birth by breastfeeding her baby daughter. Speaking in an interview, she described it as the 'best way to get back into shape', adding that she 'loves' nursing. The slender star gave birth to Rose at the start of September, reportedly marrying her French partner Romain Dauriac, 32, not long after. And despite her busy schedule, the 30-year-old told American TV channel ABC that motherhood is 'wonderful'. 'It's very, very magical – and exhausting,' she said. 'The love is unbelievable. It's very overwhelming.' She added that she doesn't shy away from late-night feeds and changing nappies either. 'I do the whole bit,' she said. 'I'm nursing and I love it.' Advertisement

Crucially, they were also a fifth, or 20 per cent, less likely to get triple negative cancer, which makes up 15 to 20 per cent of cases and is very hard to cure. It is called triple negative because it does not respond to any of three powerful treatments.

Breastfeeding lowers levels of the hormone oestrogen, which can trigger cancer. Some scientists also believe the process of producing milk stops cancer cells forming.

The researchers said nursing for three months would 'significantly reduce the risk' of breast cancer.

Dr Graham Colditz presented the findings at the San Antonio Breast Cancer Symposium in Texas. He said: 'Importantly breastfeeding was clearly protective for triple negative breast cancer – the subset of this disease for which we have limited treatment options.'

He called for 'greater public health support' for breastfeeding. NHS figures show 82 per cent of mothers start to breastfeed, but only 55 per cent do it for six weeks and just one in 100 carries on with no formula milk for six months.

Last week mothers protested outside the prestigious Claridge's hotel, in London, after a nursing woman was told to cover herself up in its restaurant. Ukip leader Nigel Farage waded into the row by suggesting on radio that breastfeeding mothers should 'sit in a corner'

In Europe, only France, Malta, Ireland and Belgium have lower rates. Breastfed babies are less susceptible to infection, allergies and obesity. Nursing promotes bonding with the child and helps a mother shed pregnancy weight, since making milk burns calories.

But many find it uncomfortable or say they are too embarrassed to do it in public due to prejudice.

Last week mothers protested outside the prestigious Claridge's hotel, in London, after a nursing woman was told to cover herself up in its restaurant. Ukip leader Nigel Farage waded into the row by suggesting on radio that breastfeeding mothers should 'sit in a corner'.

One in eight British women will develop breast cancer, with 50,000 cases and 11,500 deaths a year.