Studies in Australia
Why keeping off the Kilos reduces
by Ralph Kratzer
Most of us have more or less big problems with obesity. But in addition to the aesthetic reasons, to reduce weight, there are also medical reasons. Too much weight can cause problems for the joints and the cardiovascular system, this is well known. Studies in Australia now want to prove that losing weight can also reduce the risk for cancer:
There is a good reason to aim for a healthier weight that’s got nothing to do with looking good on the beach. After not smoking, it’s the next most important step we can take to reduce our cancer risk, says Kathy Chapman, Director of the Health Strategies Division of the Cancer Council, New South Wales.
“Many people don’t realise that overweight and obesity are risk factors for some common cancers like breast and colon cancer, as well as for less common cancers such as endometrial and oesophageal cancer. With growing rates of obesity the Cancer Council is concerned that these rarer cancers will become more common,” she says.
One reason why excess weight raises cancer risk is that too much extra fat, especially around the middle, can lead to higher levels of hormones and inflammatory chemicals in the body that encourage cancer cells to grow, she explains.
But besides helping to prevent cancer occurring in the first place, being at a healthy weight may improve cancer survival, especially with breast cancer and colon cancer, says Dr Marina Reeves, National Breast Cancer Foundation Fellow at the University of Queensland’s Cancer Prevention Research Centre.
Breast cancer now affects one in eight women in Australia while colon cancer affects one in 12 people.
“There’s clear evidence that if a woman is obese at the time she’s diagnosed with breast cancer either before or after menopause, not only is the cancer more likely to recur but she’s also less likely to survive,” she says.
What is less clear though is whether intentional weight loss after a diagnosis of breast cancer will help protect overweight women from a recurrence – there’s some evidence to suggest it can and ongoing studies overseas are currently trying to find out more.
“Where there’s also evidence for a benefit with breast cancer survival is with exercise,” says Reeves. “It helps to reduce levels of inflammatory chemicals and insulin, a hormone which can promote cancer, and these effects are independent of weight loss.”
Reeves, whose own mother died of breast cancer, believes that it’s worthwhile for women who are overweight after a diagnosis of the disease to have a shot at losing weight.
“Thanks to earlier diagnosis and better treatment, most women will beat this disease – 89 per cent of women with breast cancer will survive for five years or more after diagnosis so it makes sense to do everything we can, not only to prevent the cancer recurring, but also to prevent other diseases like heart disease and diabetes,” says Reeves.
Yet women with breast cancer who are overweight aren’t necessarily encouraged to lose it.
“We did a survey of women who’d been diagnosed with breast cancer and less than 20 per cent said they’d been advised to manage their weight,” she says. “My view is that after an initial 6 to 12 months of treatment and follow up women are often left to their own devices – yet for women who are overweight losing weight and exercising is something they can do to improve their health.”
Reeves is now recruiting women who are overweight and have been diagnosed with breast cancer in the last two years to take part in a study to see if weight loss has short term benefits such as improved general health and a reduction in markers of hormones and inflammatory chemicals that may contribute to cancer progression. But she doesn’t want women to feel that they’re to blame for the disease.
“Cancer is complex and there are multiple factors involved in what turns cells cancerous and what makes them flourish. Rather than just focussing on the cancer we want to take a broader view and say to women ‘you can survive breast cancer and now’s the time to think about what lifestyle changes you can make to improve your long term health’.”
Source: The Sydney Morning Herald