Women who lose just half a stone significantly reduce their odds of developing breast cancer, a study has found.
Researchers say that even ‘relatively modest’ weight loss has a considerable effect on the risk of the disease.
If they manage to lose two stone or more, their chances of developing breast cancer go down by a third.
Postmenopausal women carrying too much weight lower their risk of developing breast cancer by 37 percent if they lose 15 percent or more of their body weight (stock)
The study of 61,335 women over 50 is one of the largest so far to examine how weight loss reduces breast cancer risk.
For some time scientists have known that being overweight or obese is very strongly linked to certain cancers, notably breast cancer.
But until now there has been very little research into whether patients can undo this risk simply by losing modest amounts of weight.
Researchers in the US tracked the women for 14 years. Those who lost 5 per cent of their body weight were 12 per cent less likely to develop breast cancer than those whose weight stayed the same.
GUM DISEASE INCREASES WOMEN’S RISK OF BREAST CANCER BY UP TO THREE TIMES , STUDY FINDS
This is thought to be due to the bacteria that causes inflammation in the mouth entering the circulation via the gums and going into breast tissue, which can result in cancer.
Speaking of the study’s findings, Dr Nigel Carter OBE, CEO of the Oral Health Foundation, said: ‘Interestingly, this research shows that there is evidence to support the theory that gum disease can have a much larger impact on the health of our whole body.’
Severe gum disease, known as periodontitis, can affect the bones in people’s jaws and cause teeth to fall out.
Previous research reveals up to 54 per cent of adults in the UK and 47 per cent in the US have gum disease to some extent.
This is equivalent to an average 5ft 5in (165cm) tall woman who weighed 12 stone (77kg) losing 8lb (3.8kg), or just over half a stone.
If they managed to lose 15 per cent of their body weight – just under two stone (11.5kg) – their risk fell by 37 per cent.
Breast cancer is the most common form of cancer in women in the UK and one in eight will develop it at some point in their lives.
There were 55,222 new cases of breast cancer in the UK in 2014, the latest available figures, and 11,433 deaths.
The number is rising steadily due to the ageing population and lifestyle factors such as obesity.
Just over two thirds of women in the UK are either obese or overweight and so put themselves at increased risk of the illness.
Researchers believe that fat tissue releases excess amounts of the hormone oestrogen, which is thought to trigger the growth of cancerous cells.
Another theory is that people who are overweight or obese are more susceptible to inflammation, whereby their joints, tissue or organs become swollen.
This process is thought to damage the cells’ DNA – their genetic code – and trigger the development of tumours.
The results of the latest study, by researchers from the City of Hope Medical Centre in Duarte, California, and Harvard University in Boston, were presented yesterday at the San Antonio Breast Cancer Symposium in Texas.
Lead author Professor Rowan Chlebowski, from the City of Hope Medical Centre, said: ‘Obesity has been well established as a risk for breast cancer.
‘But it’s been really difficult to show whether women who are overweight or obese, who lose weight, reduce that risk.
Experts say we can all reduce our breast cancer risk by keeping physically active (stock)
‘We wanted to determine if weight loss was associated with lower breast cancer incidence, as studies have not been able to consistently show that losing weight reduces the risk of breast cancer.
‘We found that relatively modest weight loss was linked to a statistically significant lower breast cancer incidence. That’s pretty remarkable.’
The women were aged between 50 and 79 and before the study 59 per cent were either overweight or obese. Another 41 per cent were within the normal range and none was underweight. The researchers assessed how many women lost weight over a three-year period and then followed them for another 11 years.
A total of 8,175 women managed to lose weight within the initial three years. During the following 11 years, 3,061 women were diagnosed with breast cancer. The research also found that women who gained weight were more at risk of developing a less common but aggressive type of cancer.
They were 54 per cent more at risk of triple negative cancer, which is responsible for one in six breast cancers.
But they were no more likely to develop the other types of breast cancer. Charities in Britain urged women to try to lose weight particularly if they are over 50, when the risk of developing breast cancer increases greatly.
Baroness Morgan, chief executive of the charity Breast Cancer Now, said: ‘This study provides further, clear evidence that postmenopausal women can significantly reduce their risk of breast cancer by taking steps to lose weight.
‘With breast cancer incidence continuing to rise, we need to do much more to enable women and men of all ages to reduce their risk. It’s so important to remember that we can all reduce our breast cancer risk through lifestyle factors, including keeping physically active, maintaining a healthy weight throughout life and lowering our alcohol intake.’
Sophia Lowes, health information officer from Cancer Research UK, said obesity was the ‘single biggest preventable cause of cancer after smoking’.